Intel SDK-85 Users Manual

8/13/2019 Intel SDK-85 Users Manual

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SDK aSystem esign itUsers ManualManual Order Number 98 451 B

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SDK aSystem esign itUsers ManualManual Order Number 98 451B

opyright 1978 ntel orporation

Intel Corporation 3 65 Bowers Avenue Santa Clara California 95 51


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Additional-copies of this manual or other Intel literature may be obtained from:Literature DepartmentIntel Corporation3065 Bowers AvenueSanta Clara CA 95051

The information in this document subject to change without notice.Intel Corporation makes n o warrant y of any kind with regard to this material , including, b ut n ot limitedto , t he imp lied warranties of merchantability an d fitness for a particular purpose. Intel Corporationassumes no responsibility f or a ny e rr or s that may appear in this document. Intel Corporation makes noco mmi tment t o u p dat e n o r to keep current the information contained in this document.Intel Corporation assumes no responsibility for the use of any circuitry o t her t h an circuitry embodied inan Intel p rod u ct . No o t her circuit patent licenses are implied.Intel software p rod uct s are copyrighted by an d shall r em ai n t he property of Intel Corporation. Use,duplication or disclosure is subject to restrictions stated in Intel s software license, or as defined in ASPR7-104.9 a) 9).No part of this document ma y be copied or reproduced in a ny f or m or by any means wi th o ut t h e priorwritten consent of Intel Corporation.The following are trademarks of Intel Corporation and may be used only to describe Intel products:

iIiCSInsiteIntelIntelevisionIntellec

iSBCLibrary ManagerMCSMegachassisMicromapMultibus

MultimodulePROMPTProm wareRMXUPI,Scope

and the combination of ICE iCS, iSBC, MCS or R MX a nd a numerical suffix.

A164 28 25K FL


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CONTENTSCHAPTERDESCRIPTION . Move Memory Command, M 4-11Substitute Memory Command, S . .4-12CHAPTER Examine/Modify CPU RegistersHOW TO ASSEMBLE THE KIT Command, X 4-12GENERAL. 2 Programming Debugging -GETTING ORGANIZED 2 Breakpoint Facility . 4-13SELECTING TOOLS AND MATERIALS 2-2 Error Conditions - Invalid Characters. 4-13UNPACKING AND SORTING PARTS 2-3 Address Value Errors 4-13A REVIEWOF BASIC ASSEMBLY AND

SOLDERING TECHNIQUES 2-6 CHAPTER 5ASSEMBLY PROCEDURE. 2-7 THE HARDWARE

OVERVIEW 5CHAPTER 3 SYSTEM COMPONENTS 5FIN L ASSEMBLY N CHECKOUT The 8085 CPU The System Buses 5GENERAL. 3 The 8155. 5STRAPPING OPTIONS 3 The 8355 8755 5-2POWER SUPPLY WI RING. 3 The 8279 . 5-2INSTALLING LARGE IC DEVICES 3-4 The 8205. 5-2STARTING THE FI RST TIME 3-6 SDK-85 MEMORY ADDRESSING. 5-3WHAT IF IT DOESN T? . 3-7 INPUT/OUTPUT PORT ANDCONNECTING A TELETYPEWRITER 3-8 PERIPHERAL DEVICE ADDRESSING. 5-5Accessing the 8279 Keyboard/DisplayCHAPTER 4 Controller 5-5OPERATING INSTRUCTIONS PROCESSOR INTERRUPTWHAT IT DOES . 4 ALLOCATION 5-7THE BUTTONS AND DISPLAYS 4 THE SERIAL DATA INTERFACE. 5-7

Reset 4-2 CONVERTER CIRCUIT FORSubstitute Memory 4-2 RS232C SERIAL PORT. 5-8Examine Registers 4-4 ADDITIONAL INTERFACES 5-8Go 4-6Single Step 4-8 CHAPTER 6Vector Interrupt . 4-9 THE SOFTWAREProgram Debugging - THE SDK-85 MONITOR. 6The Use of Breakpoints 4-9 PROGRAMMING HINTS 6Error Conditions - Illegal Key 4-9 Stack Pointer 6Memory Substitution Errors 4-9 RAM I/O Command Status Register (CSR) 6TELETYPEWRITER OPERATION 4-9 Access to Monitor Routines 6Console Commands. 4-9 PROGRAMMING EXAMPLES 6Use of the Monitor fo r Programmingand Checkout . 4-10 APPENDIX Command Structure 4-10 MONITOR LISTINGDisplay Memory Command, D 4-10Program Execute Command, G 4-10 APPENDIX BInsert Instructions into RAM I 4-11 I GR MS

ii i


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Figure 1 1 SDK 85 System sign t

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The MCS-85 System Design Kit SDK-85 containsall the parts with which you can build a complete8085 microcomputer system on a single board, anda l ibrary of MCS-85 literature to help you learn touse it . The finished computer has the followingbuilt-in features:

High-performance, 3-MHz 8085A cpu 1.3 instruction cycle Popu lar 8080A Instruction Set Di rect Teletypewri ter Inter face Interactive LED Display Large Wire-Wrap Area fo r Custom-DesignedCircuit System Monitor Software in ROM

You can assemble the kit in as little as 3 to 5 hours,depending upon your skill and experience at buildingelectronic kits. Only a 5 Volt power source capableof delivering 1.3 Amperes is then needed to makethe computer operate, using its built-in display andkeyboard. If you wish to interface a Teletypewriterto the SDK-85, you will also need a -1 0 Volt powersupply. After you have completed the basic kityou may expand both memory and I/ O by addingmore RAM-I/O or ROM-I/O devices in the spacesprovided fo r that purpose. Other spaces are allocatedfo r bus expansion drivers and buffers that allow youto address and use external devices located eitherin the wire-wrap area of the board or off the board.You can, fo r example, access up to 64 K of externalmemory via the expansion bus.

H PTER DES RIPTION

SDK-8S SPECIFICATIONS

Central ProcessorCPU 8085AInstruction Cycle: 1.3 microsecondTcy : 330 nsMemory

ROM: 2K bytes expandable to 4K bytes8355 or 8755RAM: 256 bytes expandable to 512 bytes 8155Addressing: ROM 0000-07FF expandable to OFFF

with an additional 8355 or 8755 RAM 200020FF 2800-28FF available with an additiona8155

Input/OutputParallel: 38 lines expandable to 76 lines .Serial: Through SID/SOD ports of 8085. Softwaregenerated baud rate.Baud Rate: 110InterfacesBus Al l signals TTL compatible.Parallel I/ O: A ll signals TTL compatible.Serial I/O: 20 mA current loop TTY.Note: By populating the buffer area of the board

you have access to all bus signals whichenable you to design custom system expansions into the kit s wire-wrap area


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InterruptsThree Levels: (RST 7.5) - Keyboard Interrupt

(RST 6.5) - TTL InputI NTR - TTL Input

DMAHold Request: Jumper selectable. TTL compatible

input.

SoftwareSystem Monitor: Preprogrammed 8755 or 8355

ROMAddresses: 0000-07 FFI/O: Keyboard/Display or TTY (serial I/OLiteratureDesign Library (Provided with kit : SDK-85 User s Manual

Microcomputer Systems Databook MCS-85 User s Manual 8080/8085 Assembly Language ProgrammingManual

Physical Characteristics

Width: 12.0 in.Height: 10 in.Depth 0.50 in.Weight: approx. 12 oz.Electrical Characteristics (DC Power Required)Vee: 5V 5 1.3A -VTTY : -10V 10 0.3A(V required only i f teletypewriter is to be connected to the kitEnvironmentalOperating Temperature: 0-55C

Figure 1 2 Finished Computer

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2 GENER LDon t unpack your parts yet. Do a little readingfirst, and you may save yourself time and expense.I CAUTION I

The metal-oxide-semiconductor MOSdevices in this kit are susceptible to staticelectricity. Do no t remove them fromthe protective, black foam backing sheetuntil yo u have read th e precautions andinstructions in paragraph 2-4.

This manual was published only after the assemblyof several kits by a number of persons of varyingexperience. In this chapter yo u w il l f in d v ir tu al lyeverything you need to know to put together yourMCS-85 System Design Kit.There are suggestions fo r laying ou t an efficientwork area. Al l of the tools and materials you needare described in a checklist. There is a completeand detailed parts list. Basic assembly and solderingtechniques are reviewed. Following th e step-bystep assembly ins truc tions in this chapter, youcan t go wrong.If you re an experienced kitbuilder you alreadyknow that it s no t a bad idea to read through thisentire chapter fir st, before starting the job. That

CHAPTERHOW TO ASSEMBLE THE KIT

way, there won t be any surprises later. Take yourtime. Don t rush, and don t skip over quality-checking each step yo u perform. Desoldering,removing, and replacing just one DIP componentbecause i t was no t oriented properly when firstinstalled will cost yo u more time than doublechecking of them. Your objective is surely toproduce a working computer, no t to win a race

GETTING ORG NIZEBefore starting work it s a good idea to plan andorganize your workplace. Be sure you have roomto accommodate this book lying open, and alsothe circuit board, along with tools and th e hotsoldering pencil . Unless yo u have th e cordless,battery-powered soldering instrument, you ll wantto arrange its cord out of th e way to keep fromaccidentally p ull in g th e soldering pencil off itsholder. A muffin pan, an egg carton, or some smallboxes could be used to sort parts into i f yo u don thave the traditional plastic, compartmented partsboxes. It might be helpful , too to write th e pa rtvalues and reference designators on small cards asyo u sort them, and pu t these with th e parts fo rquick identification. Arrange everything withincomfortable reach, and you ll do the jo b quicklywith Iittle chance of errors.

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2-3 S L TING TOOLS NM TERI LS

These tools and materials will be required toassemble the kit:o Needle-nose plierso Small Phillips screwdrivero Small diagonal cutterso Soldering pencil, no t more than 30 watts,

with extra-small-diameter tip. 1/16 in. isn tto o small.) You should also have a secureholder fo r it .o Rosin-core solder, 60:40 60 tin), smalldiameter .05 in. or less wireNote: Soldering paste is no t needed. The

solder will contain sufficient flux.o Volt-Ohm-Milliammeter

PHILLIPSSCREWDRIVER

NEEDLE-NOSEPLIERS

DIAGONALCUTTERS

VO L T-OHM-MILLIAMMETER

, : R ID~ O P ~ ~ ~ K

It is also useful to have the following:o Soldering aid, with a small-tipped fork at one

end and a reamer at the other, to help incoaxing component leads into holes andmanipulating small parts.

If you should happen to make a soldering error andh ve to remove solder from joints, the jo b will bemade much, much easier i f you have the following:o Solder sucking device, either the bulb varietyshown) or the pump varietyo Large-area desoldering ti p fo r your soldering

pencil, to spread heat over several leads of nIC device at the s me time

o Length of copper braid to sop up solder like aspongeNote: It is extremely diff icul t to remove DIP

components using just a solderingpencil.

2-2

SOLDERSUCKER

DESOLDERINGSOLDERING

ID


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2-4 UNP KING ND SORTINP RTS I CAUTION

The MCS-85 System Design Kit is shipped skinpacked on a card that includes a conduct ivebacking to protect its metal-oxide-semiconductorMOS devices from static charge. Don t remove thefour larger-size Intel devices from the foam backinguntil you have completed all of th e instructions inth is chapter and are ready to place them on theboard. As a further protect ion. against possibledamage, these four devices are to be installed insockets, rather than soldered on the board.

Don t remove the other componentsfrom the skin-pack. The black foambacking is an electrically conductivematerial that protects the integratedcircuit devices from static electricity aswell as from physical damage to theirleads and ceramic substrates.

Underneath the tw o bags of small parts andhardware will be found:

With a knife or sharp-pointed scissors, slit the filmaround the edges of the small-parts bags in th elower left corner of the skin-pack and removethem. First, open the bag of hardware and check tobe sure you have:

Red plastic window covered with protectivepapero Tw o strips of double-coated adhesive tape

9 nuts @

o 9 screws, 3/ 4 in. long ijj j jjjmiijijwmy

18 Nylon washers @ ADHESIVETAPE

RED PLASTICWINDOW FILTER)

9 rubber feet

9 Nylon spacers, 7/16 in. long

o

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Resistors, 1 Watt

Resistor, 12 Watt

R1

C1

C5 20

c;;;;;;;= ==? F ~100 Ohm brownblack-brown

22 p.f 15V

1 p.f 25V

:;:;

1 ==8llllJ==::Jo 200 Ohm red-black- R34

browno 430 Ohm yellow- R35orange-brown

o

o

o 2

Capacitor, tantalum

Capacitor, mono

Next, open the bag of electrical parts and sortthem out by type and value. Give yourself plentyof unobstructed work space and tr y not to let tinyparts skitter away from you. The bag should yieldthe following:Resistors, 4Watt


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Capacitor, ceramic104

o 6 alphanumeric LED lig ht -emit tin g diode)displays

D51-6o 24 pushbutton switches, with keycaps labeled

o 7 0 1 lf e11-16,18Transistor

o 16 2 N2 90 7 transistors 01-16 51-24

Besides the small-parts bags the skin-pack contains:

A16

A lA1 4

A

8085A microprocessor cpu)8355 or 8755) ROM read-onlymemory) with I /O input/output) ports8155 RAM random-access, read-write memory) with I/ O portsand timer8279 keyboard/display interface

Note: It s a good idea to check all switcheswith the ohm meter before install ing.If one is bad, you ll save a lo t of work.

Large, 40-pin ICs integrated circuits)

o

oo

o

Y1.144 M Hz

Crystal, clock

o 4 40-pin DI P dual in-line package) socketsfo r the four large integrated circuits included in the ki t

o

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Small 16 pin s

D 1 1

8205 address decoder74LS156 scan decoder

A10A12

bottom or left-to-right, and to form theleads of parts with values printed on them sothat the values are legible after assembly.

3 Fit each part in place and see that no unduestress is placed on the leads. Double-check andbe sure you have the correct part inserted inthe correct holes, properly oriented. Don ttrim leads before soldering.I CAUTION

Large-scale integrated circuits are fragileDropping, twisting, or uneven pressuremay break them. The discharge of staticelectricity can destroy them internally.Leave them embedded in the conductivefoam backing sheet until ready to installon the board. Never press down hardupon, twist, or bend the larger devices.Touch the exposed metal traces of theboard with your hand before insertingone in its socket. The soldering of largedevices directly on the circuit board isno t recommended.

2 5 A REVIEW OF BASICASSEMBLY ND SOLDERINGTE HNIQUES

The steps to producing a professional qualityassembled circuit board are:1 Have your work area organized before starting

work, and keep i t that way. See paragraph2-2.) Sort all parts into bins, cups, trays orboxes so they wil l be easily located by valuewhen needed.

2. To prepare a part fo r soldering, bend its leadscarefully with needle-nose pliers to make thepart f it exactly the way you want it to.

It is good practice to orient color-coded resis-tors so that the codes are readily read, top-to-

2-6

4 When ready to solder, be sure your solderingpencil is hot enough to melt solder quickly.Then turn the board face-down on your worksurface. If necessary, hold the parts you areabout to solder in place while turning it overso they won t fall out, and place somethingunder the board to hold the parts in positionwhi le you solder on the back surface of theboard. Some people prefer to crimp the leadsto hold the parts in place. That s all r ight, too.

5 Bring the point of your soldering pencil intocontact with the pad to be soldered, simultaneously also touching the lead.

6. At once, touch the end of the solder wire tothe pad and lead, opposi te the pencil tip. Theamount of time required to melt the solderwill depend upon the amount of foil surfacethere is on the board to carry away heat byconduction. The smallest pads will heat up inless than a second with a 25- or 30-wattpencil; large, ground-plane areas may requireover five seconds.

7 The instant you see and feel the solder start tomelt, withdraw the solder wire from the joint.Only a tiny drop of solder is needed to make agood joint.

8 The instant you see the solder draw into thehole, become shiny, and spread smoothly overthe surface of both pad and lead, withdrawthe soldering pencil. It will take only amoment fo r th is to happen after step 7

9. Don t reheat a joint unless there s somethingwrong with it : not enough solder, too muchsolder (causing a bridge to an adjacent pador trace), or a cold solder joint, which


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appears dull on the surface or does notsurround the lead completely and fill the hole.Note: A little rosin from the solder core,

remaining on the board, does no harm.Don't tr y to clean it off.

light between the soldered pad and any adjacentpads or traces that aren t supposed to be connectedto it , it might be well to sl ip a solder-sucker or wickover the lead under examination, quickly remeltthe solder and draw off the excess.

2-6 SSEM LY PROCEDUREFollow these instructions in order and make acheck mark in the box opposite each step when itis completed.

I

IIIII

D First, place the board on your work surface,lettered side up.

D Install the nine rubber feet. Eight go aroundthe edge of the board, and one goes near themiddle of the board, to the left of the keyboard and display area. At each location, pressa nut into the recess in a rubber foot, string awasher on a screw, and insert the screwthrough the hole in the board from the top.

Place a spacer, then another

washer on the screw, thenplace the nut and foot onthe end of the screw, andtighten, with the screwdriver,just enough to hold the footfirmly.

Note: Do not apply soldering paste to the work.Fluxing is not required in printed-circuitsoldering, as the boards and componentleads are plated or tinned to prevent oxidation of the copper.

2. Use enough heat to cause solder to flow intothe hole in the board and around the leadthat s being soldered into i t.

WARNING

1. Use no more heat than absolutely the minimum that wil l make a sol id joint.

10. CI ip off the excess length of lead that projectsbeyond the solder bead, within 1/8 inch ofthe board. Save cut ends to use for strappingoptional connections. See paragraph 3-2.)

There are two important conditions that governgood soldering technique. They are:

Avo id eye injury when clipping excesslead ends. Hold lead end as you c lip it ,so it can't fl y up in your face.

These conditions are both met simultaneously andeasily only if you are careful, have the proper tools,and arrange your workplace so that the circuitboard can lie flat while you apply steady, firm (butnot hard) pressure with the soldering pencil withoutslipping. A small-diameter soldering ti p is a mustLikewise, small-diameter solder wire is essential toachieving satisfactory results.

Always inspect careful ly fo r cold solder joints,solder bridges, or (perish the thought ) l ifted tracesafter each soldering operation. A good way tocheck fo r solder bridges is to hold the newlysoldered connection up to a l ight. If you can't see

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o Install capacitor C1 near the top edge of theboard.

o Solder C1 in place. Clip excess lead ends.

WARNING Avoid eye injury. Hold lead ends as youclip them so they can t fl y up at you.

Assembly of TTY Interface Area

oo

J

< l

o

a9

.

POWER

~ : J ~ ~GNDERS o

o Install a 100 Ohm, 1/2 Watt resistor brownblack-brown at R1.Install a 4.7k Ohm resistor yellow-violet-redat R2.

/Install a 1.6k Ohm resistor brown-blue-redat R3.Install a 1k Ohm resistor brown-black-red atR4.

o Install a 47 Ohm resistor yellow-violet-blackat R5.

o Install a 2.7k Ohm resistor red-violet-red atR6.

o Solder the six resistors in place, then clip theirexcess lead ends.

o Install a 1 uf capacitor at C5, and solder andclip it.o Install a 200 Ohm, 1 Watt resistor red-blackbrown at R34.

o Install a 430 Ohm resistor yellow-orangebrown at R35.

o Solder these two resistors in place, then cliptheir excess Iead ends.o Install transistors Q1 and Q2, and solder and

clip them.

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o A 16, for the RAM-I/O device an 8155.o Solder the three sockets in and check carefully

for solder bridges

9 11

GO

VECTINTR

OSl

RESET

SINGLESTEP

C20 SUBST EXAM R3 MEM REG e=t R32Q NEXT EXEC

?\ 0Q4 2V _NCiCi

ADDRESSDECODER hEYBO

- l o A ~ ou L LO

8755 (8355)LOC 0800H OFFFH

PORTS 8H BH

3 4 ~ C

8155LOC 2800H-28FFH

PORTS 28H-20H

7 8 9ClK

283 A 5

20 2

IPORT I

IPORT

l IPORT 9~I l

TIMER oUT/IN

IPORT 2AH lIPORT 29H l

LJLJn

I 3 32ORT J 3H

I33

PORT 2 2H~ IPORT 21t~

N N

C 9LJ A 7J5

,PORT 2BH J

L J

Assembly of Processing AreaThe processing area includes the clock crystaladdress decoder cpu RAM-I/O and ROM-I/O areasand related components

i..

o Install the crystal at Y1 with its leads bent sothat the device lies flat on the board in thespace outlined for it

o Take a piece of scrap wire trimmed from acomponent previously mounted on the boardBend it into the shape of a staple Install itover the crystal to hold it firmly in place

o Solder the four connections just madeo Install the 8205 address decoder at A 10 and

solder it

o A11 for the 8085 cpuo A 14 for the PROM ROM -I/O device an

8755 or 8355.

Install three DIP sockets crimping the corner leadsof each to hold in place at:

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Install 0.1 uf ceramic capacitors at:

oo

Install a 3k Ohm resistor orange-black-red atR7Install a 3 9k Ohm resistor orange-white-redat RBSolder these two resistors and clip of f theirlead ends.

ooo

C16C1BNow solder the capacitors you have installed,and clip of f their excess lead ends.

Install three 0.1 uf ceramic capacitors at:

L J

9 11

RESET VEerINTR] SINGLE GOSTEPSUBST EXAM

R3 ME M REGR3

NEXT EXEC

8085

ADDRESSDECODER KEYBD

__

KEYBOAR

LOv ... j

8755 83551LaC OOOOH-07FFH

PORTS 3

8755 8355La C 0800H-OFFFH

PORTS 8H BH

5 6

3 4 C 7

81S5LOC 2800H-28FFH

PORTS 28H-2DH

8155LaC 2000H-20FFH

PORTS 20H-25H

A 5

.. PROM ROM I/ O

7 8 9CLK

TIMER oUT/IN

IPORT 2AH~IPORT 29H

LJLJnIPORT I 20 IPORT 0~IPORT 9I

M M

L J 8n 30I 31PORT 3

I 33PORT 22H~ A 6IPORT 21H~

N N

C 9 AI7J5IPORT 28H

C11C12C13Solder them and clip off excess lead length.Install a 1 uf capacitor at C20.Install a 1k resistor brown-black-red at R31.Install a 5 k resistor green-brown-orange atR32.Install a 2 Ohm resistor red-black-brownat R33.Solder these four components in place andtrim their leads.

ooooooo

oo

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Assembly of Keyboard and Display AreaFind where the row of resistors, R9 through R30go Install eight 3k resistors orange-black-red) at:

lESSJER hEYBOARD AND DISPLAY ] H s c ~ J S b ~ ~ O E R ~ Q v1ou KEYBOARD D I : ~ : : Y CONTROLLER LOC 1 80 0H1900H

9

S25KEYBOARD: ~ 1 2 2

S E T L ~ ~ 1 2 3i

1 12 DISPLAY DRIVERS I 124

D ~ ~ 6 ~ ~ D ~ ~ D ~ N D ~ ~ D ~ r : l ii X i ~ ~ d l m . r i ~ Q ~ h ~ a ~ a ~ a ~ h 6~ _ O _ l l _ ~ ~ ~ S O I 4 I 5 - ~ A - -

_DS_l DISPLAYS ~ D _ S 6 J 1

D R9D R12D R15D R18D R21D R24D R28 Careful-the location pattern changes

here )D R29D Now solder all eight resistors in place and clip

their excess lead ends.

RESET VECT DINTR

SINGLE GO 8 ASTEP H

SUBST EXAM S 6 7MEM REG SPH SPL PCH PC L

XT EXEC

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Install six 270 Ohm resistors red-violet-brown at: A7 ~ D A T A uius BUFF ~ ~ J V VDRESSCODER hEYBOARD AND DISPLAY2 5 ] 25 S 74LS 56 l n6 A 1 2 ~ SCAN DECODER I I

27 L

I ~ ; O ~ ~ ; ~ ~ N m C24

S25

7PC L

o

KEYBOARDTTYSELECT

6PCH

5SPL

o

SPH

EXAMRE G

EXEC

2 D ISPLAY DRIVERS 6 r \ . _NY: ; OOC,O_ r ../ / _ 1 ~ ~ Cl Cll O O C l C l C C l l

9

NEXT

SUBSTMEM

R10 R13 R16 R19 R22 R25 Solder these six resistors and clip their excess

lead ends

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A7 DATA ius UFF jAf . . JUIDRESSO ER]hEYBOARD N DISPLAY205 ] 25 74LS156 lJ I A CAN om

KEYBOARD DISPLAY CONTROLLERLOC 1800H

1900H

Install eight 24 Ohm resistors red-yellow-black at: R

R14 R17 R20 R23 J R26 R27 Again, note the change in locationpattern.

R30 Solder these eight resistors and clip their

excess lead ends

SU ST

N XT

9

EXAMRE G

EXEC

4SPH

o

5SPL

S

KEYBOARDiTTYSElE T

6PCH

7PCL

o

24

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24

525

_.

16

A

82 DISPLAY DRIVERS

4 7

GO

VECTINTR

3

9

9ri ~ ~ ~ ~t ~ @W@W L ~ 6 ~ ~

A7DATA -BUS BUFF tt[ ~ _ v v JAf JJ IDRESSCOOER 1hEYBOARD AND DISPLAY205 ] 25 74LS156 lA12 SCAN D E C O D E R ~ I AI3 v

J OVA KEYBOARD CONTROLLER LOC 1800H1900H11 2 3 0 [ J r J ~ a O A ~

I 51 56DISPLAYS

]

RESET

SINGLESTEP

Install fourteen 2N29 7 transistors in two rows.Position the seven transistors in the top row so thattheir indexing tabs point upward and to the left at:o Q3o Q4o Q5o Q6o Q7o Q8o Q9Position the seven transistors in the bottom row sothat their indexing tabs point down and to theright at:o Q10o Qo Q12o Q13o Q14o Q15o Q16o Press all of the transistors down to about

1 8 inch from the surface of the board. Letthem stand approximately straight up. Thenturn the board over and solder all of theirleads in place and trim the lead ends

sUBsTMEM EXAMREG

4sPH

5sPL 6PCH 7PC L

NEXT EXEC o

o

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Install tw o 1 uf ceramic capacitors at:

Be careful to orient the six alphanumeric LEDdisplays so that t he decimal point s are even withthe bottom of the digits and install at:

5 5

KEYBOARD:S E T L ~ ~ T 23

DS6

RESET VECTINTR

SINGLE GO ASTEP

SUBST EXAM 4 5 6 7MEM REG SPH SPl PCH PC L

NEXT EXEC

DS1DS2DS3DS4DS5DS6

Note: on tinstall the red filter over th e displayyet. It s a good idea to wait until after finalassembly and checkout to do this on theremote chance that you might have toremove one of the character displays.

o C14o C15o Solder the leads and clip them off close to the

board.

Note: If these components are provided with longwirewrap leads you will probably find iteasiest to insert solder and clip t hem oneat a time because of crowded quarters. Theorder shown above with t he board tu rn edbottomside up will be most convenient fo ryou if y ou hold t he soldering pencil in yourleft hand. If you solder right-handed youmay prefer to w or k f rom DS6 to DS 1.

oooooo

o Install one of the 40-pin DIP sockets fo r the8279 Key board-Dis play Contr ol ler at A13and solder it in.

o Install the 74LS156 scan decoder at A 12 andsolder it.

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The easiest method of doing this is to insert eachbutton in its turn bend its leads over on the backof the board to hold it in place and go on until allbuttons are in place then solder all of them in onepass with the board lying flat on the work surfaceand weighted down to make sure the switches areuniformly held firmly against the front surface ofthe board.

o RESET o VECT o E o FINTRo SINGLE o GO 8 9 o BSTEP H lo SUBST o EXAM 4 5 6 7MEM REG oSPH oSP l oPCH op l Instal l the twenty four pushbutton switches

that make up the keyboard. Be sure each o NEXT o EXEC o 2 Ibutton is rightside up and in its proper positionbefore soldering Al l soldered in place

2 16


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CHAPTERFINAL ASSEMBLY AND CHECKOUT

3 1 GENER LN ow t ha t most of the components are soldered onyour circuit board, i t s t ime to give your handiworka quick visual check to make sure all of th e devicesare oriented correctly. The notched ends of the ICsshou Id all be toward your l ef t, and the decimalpoints of t he LED displays should be at the bottomline of the characters.It is recommended that the basic kit computerbe checked ou t using the procedure in this chapterbefo re adding any external options such as teletypewri ter or expansion memory. I t is well fo r yo uto have the assurance that you have a working cpuand displ ay-keyboar d bef or e you add peripheralsto your system. I t is therefore recommended thatyo u first wire th e strapping options in Table 3 1fo r the 8355 or 8755) ROM-I/O that was furnishedwith th e kit and contains the SDK-85 SystemMonitor . T hen inst al l the strap in Table 3-2 fo rk ey bo ard o pe ra ti on , and in Ta ble 3-4 fo r the basickit without expansion memory. See paragraph 3-2.)Paragraph 3-3 tells you ho w to hook up power tothe MCS-85 System Design Kit, and paragraph3-4 t ell s yo u ho w to start it up and see if it sworking r ight . T he subsequent paragraphs l ist t headd-on options yo u can use without inventing anynew circuitry on the board or off.

3-2 STR PPING INSTRU TIONST he MCS-85 System Design Kit will accept 8355or 8755 ROM-I/O devices at po sitions A 14 andA 15. These different devices are no t completelyelectrically interchangeable, so yo u m ust make thestr appi ng connect ions in T able 3- 1, appropr iate tothe type of device in each socket.

To make a stra ppin g c on ne ct io n j um pe r) , bend ashort l engt h of bare wire such as the excess leadend cut from a r esistor) to fi t between the tw oholes you wish to strap t oget her, i nser t th e endsof th e wire in the holes, and solder th em. Thencl ip the remaining excess ends, just as yo u di d witht he com ponent s. When you in sta ll a jumper andsolder it , be sure it doesn t touch any interveningtraces or pads.IMPORTANT: For normal operation of t he SD K85, it is m n tory to strap the following:

1. One of t he t hr ee options in Tab le 3-1.2. One of the tw o options in T able 3-2.3. The tw o jumpers l isted in Table 3-3.4. Either basic kit operation or one of several

expansion options listed in Table 3-4.The keyboard-teletypewriter selection function maybe done with a min ia tu re p ri nt ed c ir cu it -b oa rdmount, single-pole, double-throw swi tch, S25, no tfurn is hed in th e kit, or may be strapped withwire. Table 3-2 lists the connections. Table 3-3lists keyboard strapping connections always made.Tables 3-5 through 3 -1 0 l is t all of t he bus and portexpansion connector pinouts. Table 3-11 listssuggested connector types.

3-3 POWER SUPPLY WIRINGSee Figure3-6.)Co nn ec t a + 5 Volt, regu lated power supply with itspositive output at the +5 V POWE R SUPPLY pointon th e board. A 6-pin Molex connector will f it the

Text continues on page 3 4.;

3 1


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TABLE 3ROM/PROM STRAPPING

Device 8355 8755 8755ALocation Figure 3 Figure 3-2a Figure 3-2b

A14 Strap Strap The SDK-85Monitor No Straps 28-29 29-30ROM) Required Strap StrapA 5 31-32 32-33

Figure 3 No Strapping Required fo r 8 55 ROMsTABLE 3-2TELETYPEWRITER-KEYBOARDSTRAPPINGTELETYPEWRITER KEYBOARDFigure 3-3 Figure 3-4

Strap 22-23 Strap 23-24

TABLE 3-3DISABLING UNUSED KEYBOARDCONTROLLER FUNCTIONS

Figure 3-5Always strap 9-10.Always strap 11-12.Note: These two straps not usually removed,since the MCS-85 System Design Ki tdoes not have SHIFT or CONTROLkeys on its keyboard. These straps

have no effect on operation of thecorresponding key functions on ateletypewriter or other ASCII terminalthat is connected to the TTY interface.They are provided fo r your use if youwish to modify the SDK-85 s keyboard functions and replace its monito r software with your own.

Figure 3-2a Strapping Connections fo r 8755 PROMS

3-2 Figure 3-2b Strapping Connections fo r 8755A PROMS


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u_

Figure 3 5 Disabling Unused Keyboard Controller Functionseletypewriter Strapping Connection

Figure 3 6 Power Supply Connections

T ~ N T

q 1 VOLT SUPPLY

6 745 IMJ 74 5742 6

5 VOLT SUPPLY

1 J A7

5 A

3 3


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hole p at ter n on the board see p. 3-13 fo r the partnumber). If you are going to use a teletypewriter,connect a 10 Volt power supply with its negativeoutput at the 10V point on the board. Connectthe positive side of the 10 Volt power supply tothe G ND bus.

ICAUTION Do no t turn on power until instructed to do so.

3-4 INSTALLING LARGEIC DEVICESWhen you ve f inished all soldering operations onthe board and are ready to fire it up, then it s timeto plug in the large ICs. Once more, please makenote of the precautions fo r handling these largeMa S devices.

ex t continues on page 3 6.

TABLE 3-4BUS EXPANSION STRAPPING

FUNCTION

RST 6.5

HOLD

INTR

MemoryAddress

Locations

BASIC KI TWITHOUT EXPANSION

MEMORY Figure 3-7)Strap 3-5

Strap 6-8

Strap 20-21

Leave 25-26-27 unstrapped.

AUGMENTED KI TWITH EXPANSION

MEMORY Figure 3-8) Also See Paragraph 3-7.)

Strap 3-4 if no input is connected to 1-20. Leave 3, 4, and 5 no t strappedi f input is to be supplied fo r thisrestart function.Strap 7-8 if no input is connected to 1-14. Leave 6, 7 and 8 no t strappedif input is to be supplied fo r th isfunction.Strap 20-21 if no input is connectedto 1-18. Leave 20-21 no t strappedif input is to be supplied fo r thisfunction.Strap 25-26 i f all memory locationsare external, i.e., addressed via busexpansion drivers. * See Figure 3-9.)Strap 25-27 to enable the bus expansion drivers only when the upper 32 Kmemory locations 8000H-FFFFH)are addressed. See Figure 3-10. )

* Note: No devices may be instal led in posit ions A 13, A 14, A 15, A 16, and A 17 i f this optionis strapped.

3-4


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74LI116 r ISCAN DECODER I u

SO 10 iii AIDU.::> C,,,r- I IVl I - Iyen..:>

AlE 5 ] [ A ~ Cl . 8212HOLDINT I A ADDRESSINTR DRIVERRST6.5RESETRSTINI m I

A7 A6

I ] .8212 } 8216 AD A7 ADDRFSSEO AO DRIVER. ; A7 DATA 8US BUFFL L-Jn

8 85

C9

8279KEYBOARD DISPLAY CONTROLLER

LOC lB H19 H

lI II I

Figure 3-7 Strapping Required for sic Kit No us Expansion

L J L-Jn

Figure 3-8 Strapping Options for us Expansion Control Lines

J7

121

2~ E Y O R D I

Figure 3-9 Strapping Options for all External Memory Figure 3-10 Strapping Options for Internal /External Memory

3-5


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I CAUTION Large-scale integrated circuits are fragileDropping, twisting, or uneven pressuremay break them. The discharge of staticelectricity can destroy them internally.Leave them embedded in the conductivefoam backing sheet until ready to installon the board. Never press down hardupon, twist, o r bend the larger devices.Touch the exposed metal traces of theboard with your hand before inser tingone in its socket. The soldering of largedevices directly on the circuit board isnot recommended. I f your Kit is provided with 8755 EPROM, do no t removethe opaque sticker covering the window.Ultraviolet radiation including sunlight,can erase the monitor software containedin the device.

Inspect each IC to see that its leads are reasonablystraight. (It s okay fo r the device to be a bi t bowlegged. The forked end of the soldering aid is agood tool fo r straightening bent leads. Carefullyplace an I C on its intended socket, oriented properly, with one row of its pins resting lightly inthe socket holes. With your fingers or with the soldering aid, gently tease the other row of pins intotheir socket holes. e sure no single pins have es-caped. Once all pins have started, press downgently with fingers or with something flat to seatthe device in its socket.Each device must be oriented properly in i ts socketor it won t work. Every DIP device made has eithera notch of some kind or a do t at one end. On theSDK-85 board, each notch or mark must face tothe left. The markings on the board indicate thisorientation. They also show which device typegoes where. See the p ictoria ls on pages 2-9 and2-15.

3-6

5 ST RTING THE FIRST TIMOnce you are certain that all parts are properlyinstalled, the correct strapping options are soldered,and t he power supplies connected, you are readyto start your MCS-85 System Design Computer.Clear the surface of your work table of any toolsor wire that could come in contact with the underside of the circuit board and short it , and be surethere aren t any wire clippings on top of the boardby accident.Peel the coverings from the red window and lay iton the display. (Don t stick i t down yet.Energize the +5 Volt power supply.Press the button on the keyboard. The displayshould respond by reading ou t 80 85.If the above readout appears, go on to Chapter 4 ofthis book and t y ut each button and function.Verify that each command produces the specifiedresult, and that all segments of each 7-segmentcharacter display light.Once you know the displays are all working right,peel the backing from the two strips of doublesided tape and use them to stick the red window inplace.


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3-6 WHAT I F IT DOESN T?I f t here is no response to the 8 command,D Use the multimeter to check fo r the presence

and proper polarity of +5 Volts on the board.D Check all of the strapping connections, and

be sure they are in the right places fo r theconfiguration you chose.

D Check carefully the seating of each and everypi n of each of the four large ICs. Be sure nopins have a cc id en ta lly b en t ov er and missedth e socket.

D Go back over the Chapter 2 assembly proced ure and scan and check off all of the component values and all of th e solder connections.

D Check th e orientation of all semiconductordevices.

D Inspect fo r solder bridges or loose solderjoints.

If all devices are properly soldered or firmly intheir sockets and still there s n o result, it can bepresumed that there is a bad part somewhere. Thekeyboard switches can be checked using the multi-meter, as mentioned in Chapter 2. If all switches areclosing positively when pressed, and opening whenreleased, further effective troubleshooting can beaccomplished if yo u have a dual-trace oscilloscopeof at least 5 MHz bandwidth or a logic analyzer.D Pin 37 of cpu 8085) should show a

clock output of 3.072 MHz 326 ns period).I f it doesn t, there s something wrong with th e8085 or th e crystal.

D Pin 30 of A should have a posit ive-goingpulse a bo ut 1 60 ns wide every JiS or so Thisis the AL E pulse that indicates that t he cpu isexecuting instructions.

D Pin 1 of address decoder A 10 8205) shoul dpulse. If not your 8085 is probably bad.

D If pi n 1 of A 1 0 pulses, check p in 15 of A 10. IfA 10-15 doesn t follow A 10-1, or has bad outpu t voltage levels, t he 8 20 5 is either bad or installed wrong.

D If all else fails, call the Intel Service Hotline anddescribe the results of the foregoing procedure.

The numbers are: 8 00) - 5 38-8 01 4 when calling from out 800) - 538-8015 side C al if or ni a 800) - 672-3507 C al if or ni a only

Note: The Service Hotline is available to provide l imit ed s up po rt to help you getyour kit running. I f we can t hel p youover the phone, yo u may be directedto return your kit to us and we ll fi x itfo r a flat fee and send i t back to you.The Service Hotline is available Monday through F rida y, between 8 AMand 3 : 30 PM, Pacif ic t ime.

IMPORTANT: T he Service Hotline t ableto provi de hel p to yo u in writing programs fo ryour kit or in making hardware mo di fica tio ns.Please rely on the documentation provided withyour ki t fo r assistance.

TABLE 3-5INTERFACE CONNECTOR J7

PIN ASSIGNMENTS

PIN MARKING ASSIGNMENT1 Open

14 - Open2 Open15 Open3 Open16 - Open4 - Open17 - Open5 - Open18 Open6 - Open19 Open7 Ground20 Open8 Open21 - Open9 - Open22 - Open10 - Open23 Open11 - Open24 RX- Receive Return -12 RX+ Receive +25 TX- Transmit Return -13 TX Transmit +

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3-7 CONNECTING ATELETYPEWRITER

If you wish to use a teletypewri ter with yourSDK-85 computer connect it at Interface Connector J7 as shown in Table 3-5. You may use eithera male connector or a female connector. See

Table 3-11. Only four pins of this connectorare assigned for Teletypewriter use; the remaining pins may be wire-wrapped to serve anyfunction you choose.

T BLE 3-6BUS EXPANSION CONNECTOR PIN ASSIGNMENTSASSIGNMENT PIN PIN M RKING ASSIGNMENT I O

GND 1 2 - OPEN -GND 3 4 ClK Buffered ClK 0GND 5 6 S Buffered S 0GND 7 8 SO Buffered SO 0GND 9 10 LE Buffered LE 0GND 2 HlD Buffered H lD 0GND 3 14 HOLD Buffered HO l IGND 15 6 INT Buffered INTA 0GND 7 8 INTR INTR IGND 9 20 RST 6.5 Buffered RST 6.5 IGND 2 22 RST Buffered RESET OUT 0GND 23 24 RSTIN RESET INPUT IGND 25 26 D7 Buffered D7 I OGND 27 28 I Buffered D6 I OGND 29 30 CfJ Buffered D5 I O

I OND 3 32 Buffered D4GND 33 34 e Buffered D3 I Oe:: I/OND 35 36 Buffered D2GND 37 38 I Buffered D I OGND 39 40 DO Buffered. DO I/O

3-8


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T LE 3 7US EXP NSION CONNECTOR J PIN SSIGNMENTS

SSIGNMENT PIN PIN M RKIN SSIGNMENT I O

GND 1 2 ROY READY I4 WGND 3 Buffered WR 0

GND 5 6 R Buffered RD 0GND 7 8 M Buffered M 0GND 9 10 A15 Buffered A 5 0GND 2 Buffered A14 0GND 13 14 Buffered A13 0GND 15 16 Buffered A 2 0GND 7 18 Buffered A 0GND 9 20 Buffered A10 0GND 2 22 CJ Buffered A9 0coGND 23 24 CJ Buffered A8 0CJGND 25 26 w Buffered A7 0a:GND 27 28 Buffered A6 0GND 29 30 Buffered A 0IGND 3 32 Buffered A 0GND 33 34 Buffered A3 0GND 35 36 Buffered A2 0GND 37 38 Buffered A 1 0GND 39 40 AO Buffered AO 0

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TABLE 3-8I/ O PORT CONNECTOR J3 PIN ASSIGNMENTS

ASSIGNMENT PIN PIN MARKING ASSIGNMENTP1-6* 1 2 l P1-7P1-4 3 4 P1-5PORT 1P1-2 5 6 J P1-3P1-0 7 8 P1 1PO 6 9 10 l 7 PO 7PO 4 11 12 f PO 5PORT 0PO 2 13 14 t PO 3PO O 15 16 P PO 1frP9-6 17 18 l P9-7P9-4 19 20 P9-5PORT 9P9-2 21 22

P9-3

P9-0 23 24 P9 1P8-6 25 26 l P8-7P8-4 27 28 P8-5PORT 8P8-2 29 30 J P8-3P8-0 31 32 P8 1

GROUND 33 34 GROUNDNote: 1 Pn-m stands fo r PORT n Bi t m e.g. P9-6 means PORT 9H Bi t 6 .

2 Ports 0 1 are Ports A and B of 8355 A 14 .3 Ports 8 9 are Ports A and B of 8755 A 15 .

3-10


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TABLE 3-9I O PORT CONNECTOR J4 PIN ASSIGNMENTS

ASSIGNMENT PIN PIN MARKING ASSIGNMENTP23H-4 1 2 l P23H-5P23H-2 3 4 PORT 23H P23H-3P23H-0 5 6 J P23H-1P22H-6 7 8 l P22H-7P22H-4 9 10 P22H-5PORT 22HP22H-2 12 J P22H-3P22H-0 13 14 P22H-1P2 H-6 15 16 l P2 H-7P2 H-4 17 18 P2 H-5PORT 2 HP2 H-2 19 20 J P2 H-3P2 H O 2 22 P2 HOPEN 23 24 OPEN

GROUND 25 26 GROUNDNote: rt is rt Iort 22H is Port B of8155 A16 .

Port 23H is Port C

3-11


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TABLE 3-10I O PORT AND TIMER CONNECTOR J5 PIN ASSIGNMENTS

ASSIGNMENT PIN PIN MARKING ASSIGNMENTP2BH-4 1 2 l P2BH-5P2BH-2 3 4 PORT 2BH P2BH-3P2BH-0 5 6 J P2BHP2AH-6 7 8 l P2AH-7P2AH-4 9 10 P2AH-5PORT 2AHP2AH-2 2 J P2AH-3P2AH-0 13 14 P2AH-1P29H-6 15 16 l P29H-7P29H-4 7 18 P29H-5PORT 29HP29H-2 9 20 J P29H-3P29H-0 2 22 P29H-1

-Timer OUT 23 24 TIMER Timer InOUT IN

GROUND 25 26 GROUNDNote: Port H Port A }Port 2AH is Port B of expansion RAM 8155 A 17 .Port 2BH is Port CTimer is on the same 8155 A17 .

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TABLE 3 11SUGGESTED CONNECTOR TYPES

REFERENCE FUNCTION NO OF MFR. MFR S.DESIGNATION PINS PART NO.J us Expansion 40 Spectra Stri p 800 576J2 us Expansion 40 Spectra Strip 800 576J3 I O Ports 34 Spectra Strip 800 579J4 I O Ports 26 Spectra Strip 800 583J5 I O Ports and Timer 26 Spectra Strip 800 583J6 Not UsedJ7 TTY Interface 25

em le} Optional AMP 206584Male AMP 206604 Power Supply 6 Molex Model No. 1261Recepticle 03 09 1064

Plug 03 09 2062

3 13


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4 1 WHAT IT DOESThe things you can do with the basic SDK-85 kitare:

Examine the contents of all memory and reg-ister locations Deposit program steps or data in RAM orregister locations Execute programs or subroutines uponcommand Reset start the monitor upon command Interrupt and start operation at a location

you specify upon commandYou may select either the keyboard and display onthe board or a teletypewriter as the console deviceby operating a switch or by placing a jumper wireat the appropriate place on the board. See Chapter3. Keyboard/display operation and teletypewriteroperation are described separately in the followingparagraphs.Two of the keyboard buttons continue to functionin teletypewriter mode, as well as in keyboard/display mode. These are the and the ll keys.4-2 THE BUTTONS AN D DISPLAYSKeyboard/display operation is done by pressingkeys on the keypad. Responses are displayed eitherby echoing the key pressed or by prompting youwith a message or prompt When the 8 button ispressed, the monitor is ready to accept commands.For numeric arguments, the valid range is from 1to 4 hexadecimal digits fo r address information and1 to 2 hex digits fo r register and memory data.Longer numbers may be entered, bu t such numberswill be evaluated modulo 216 or 28 respectively,

H PTER OPER TING INSTRU TIONS

i.e., only the last four or the last tw o digits en-tered wi II be accepted.As noted, the number system being used in theSDK-85 is the hexadecimal, or base-16 numbersystem. Table 4 1 l ists the hexadecimal, decimalbase 10 , and binary base two equivalents. Thetable also shows how each hex digit will appear inthe seven-segment LED displays.

TABLE 4 1NUMBER SYSTEMS

LEDHE X DECIMAL BINARY DISPLAY

0 0 0000 1 1 0001 ,,2 2 0010 3 3 0011 4 4 0100 LI5 5 0101 6 6 0110 7 7 0111 ,8 8 1000

1001 A 10 1010 B 11 1011 C 12 1100 LD 13 1101 IE 14 1110 F 15 1111

4 1


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Whenever th e monitor expects a command, the display shows a dash - ) at th e lef t edge of th eaddress field possibly along with an error message . When th e monitor expects a parameter, adecimal point will be displayed at th e right edge ofth e field into which th e argument will be placed. Aparameter wi II be either an address or a byte ofdata which is used dur ing th e execution of acommand.In the descriptions of th e command modes, uppercase letters and numbers enclosed in boxes represent keyboard keys. Words or phrases in lower caseenclosed in brackets describe the nature ofthe command parameters you may input .The in the Format Statement indicates an optional argument.

Reset:The EJ key causes a hardware reset, and startsthe monitor. The message -80 85 will be displayed across the address and data field of the display if you are in display-keyboard mode. If inteletypewriter mode, the sign on message SDK-85VE R X.X will be printed. The monitor is ready toaccept a command after a reset, and saves no information about the state of any user program beforethe reset.

4

Substitute Memory:~ a d d r e s s ~ t ~ t The subst itute memory command allows you toread the contents of ROM memory and to examineand modify the contents of RAM memorylocations.The address argument denotes t he con tent s of th ememory address to be examined, and may be from1 to 4 hex digits. If you enter longer numbers, onlythe last 4 digits entered are used . As soon as th enumber is terminated by th e key, the contentso f tha t location are shown in the data field, alongwith a decimal point at the right edge o f the field.Enter ing a new number will cause that number tobe displayed in the data field; however, th e contents of the memory location will no t be changeduntil an or key is pressed.Pressing Jwill place the contents displayed in th edata field into the displayed memory address. Thenthe address and contents of th e next higher memory location will automatically be shown. Pressing will place th e contents displayed in th e datafield into the memory address displayed in the address field, and will also terminate th e command.Pressing Jwhile the address FFFF is being displayed will cause address 0000 to be displayed.


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SUBSTITUTE MEMORY EXAMPLE 1Using to list the first few Monitorlocations:

Whenever the command changes the contents of amemory location, it also verifies that the changeh s occurred correctly. If the contents of the location do not gree with what the new value shouldbe i.e., if the memory locat ion is in ROM or isnonexistent , n error mess ge is generated.

KEYISu STI

ADDR

0000.0000000100020003

DATA

3E.00.32.00.

SUBSTITUTE MEMORY EXAMPLE 2Using to enter a small program:

KEY ADDR DATA

0 0002.[] 0020.[] 0200.[] 2000. 2000

2000 03.0 2000 3E. 2001 G J 2001 04.

2001 47. 2002 [I] 2002 oc

2002 CFElNOTE: represents unpredictable values.After loading the above program, use again to go back and check locations 20002002 to see that they contain:

CORRESPONDING8085 ASSEMBLYLANGUAGEADDRESS DATA INSTRUCTIONS2000 3E MVI A 47H2001 472002 RST 1

This program will load the A register with thenumber 47 and jump back to the monitor.

4-3


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Examine Registers: d t d t

The examine command allows you to display andmodify the contents of the 8085 CPU registers.Pressing th e key blanks both th e address anddata fields, and displays a decimal point at th e rightedge of the address field. At this point, you mustpre ss a r eg ist er key register names are denoted bylegends on the keyboard). Any other key will generate an error response.If a re gi st er key s pressed, th e name o f t he registerwill appear n th e address field, and th e contents ofthe r eg is te r will appear in the data field , a lo ngwith a decimal point at the right hand edge.Entering a number will cause th e number to bedisplayed in th e data field; however, the contentsof th e register will not be changed until an or key s pressed.Pressing will place the contents displayed in thedata field into th e register named in th e addressfield, then will display the name and contents ofthe next register n sequence SeeTable4-2). Pressing will p la ce th e contents displayed in th e datafield in th e register named in th e address field, andwill also terminate the command.Pressing whi le r eg is te r PCl s being displayedhas th e same effect as pressing .

TABLE 4-2REGISTER DISPLAY SEQUENCE

KEY/DISPLAYCODE REGISTER

A CPU r eg is te r AB CPU r eg is te r BC CPU r eg is te r C0 CPU register 0E CPU r eg is te r EF CPU flags byteI interrupt maskH CPU r eg is te r Hl CPU re gis te r l

SPH most significant byte ofstack pointer

SPl least significant byte ofstack pointer

PCH most significant byte ofprogram counter

PCl least significant byte ofprogram counter

The flag byte contains th e 8085 CPU s conditionflags.The format for th e flag byte is:The format for th e I register s th e lower 4 bits of

th e accumulator following execution of a RIMinstruction. A 1 in an interrupt mask f ie ld denotes a masked condition. A 0 must be enteredto use that interrupt.

7 o

The format for the I register s7 0

IE 7.5 6.5 5.5t INTERRUPT M SKINTERRUPT EN LE FL G

x = UNDEFINED

For more informa tion abou t th e 8085 s flags andinterrupt mask feature, consult th e MCS-85 User sManual.


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EX MINE REGISTER EXAMPLE

Using to initialize t he 8 08 5 s s tack pointerto 20C2:

EX MINE REGISTER EXAMPLE

Using to examine th e contents of the8085 s Registers:

KEYIU M

R

SPHSPHSPHSPlSPlSPl

T

0220

OC2

KEY R T

R

A b C d E F

H l SPH SPl P H PCl

or NOTE: represents th e co nten ts o f th eregister whose name is in th e address

field of the display

4 5


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Go:

G address Pressing th e B key causes th e contents o f t he pro-gram counter PCH an d PCl) to be displayed inth e addressed field along with a decimal point atth e right edge of the field. Th e program counter isavailable for change and any number entered number is optional) becomes th e new contents ofth e program counter.Pressing th e key transfers control of th e CPUto th e address in th e address field contents o f th eprogram counter). Before th e transfer of control,th e address and data display fields are cleared an dan E is displayed at th e left edge of th e addressfield.Pressing an y other key bu t generates an errormessage.Th e monitor regains control of th e CPU only aftera 8 or after execution of an RST 0 RST 1 orJMP a instruction in program.

IMPORTANT:Note that because of th e way th e GO and SINGLESTEP commands are implemented in th e Monitor

nd ~ ~ ~ ~ will no t work unless th e 8085 s stackpointer is pointing to an existing portion of RAMmemory. If at a ny t im e t he se tw o commands don tseem to be working se t SPH to 20 an d S P l to C2using then try it again. locations 20C2 to20 F F are reserved for th e monitor program there-fore th e stack pointer m us t be se t to 20C2 or lowerso as no t t o interfere with th e monitor.)

6


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GO COMMAND EXAMPLENow you can execute the program you en-tered in Example 2 of the command.First check to make sure the location program is in memory then the program will beexecuted.

Recall that this small program loads the Aregister with the number 47 and restarts themonitor. To verify that the A register nowholds 47 and to get more practice using try the following sequence:

KEY ADDR DATA COMMENTS KEY ADDR DATA COMMENT M R[2] 0002. 0 A 47. A reg now ] 0020. holds 47. ] 0200. [9] A 00. ] 2000. Now A holds 2000 3E. MVI A 47 0 2001 47. 0

2002 CF. RST 1 [2] 0002. [9] 0020. Run the small0 Program again[2] 0002. ] 0200. ] 0020. ] 2000.[9] 0200. - 80 85 ] 000. R

- 80 0 A 47 Now A holds85 47 againNOTE: denotes don t care values Now tr y placing other values in location 2001using and use 0 to execute the programagain seeing how those values are loaded intothe A register after execution.

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SINGLE STEP EXAMPLE

To resume full speed operation at this point ,do the following:

Single stepping through the SOK-85 Monitor.This is what you should see on the display:

E1F5E1

E185

DATA

0010.- 80

KEY ADDRSIN LT

000a. OOOb

OOOCOOOF0010.

Single stepping is implemented in the SOK-85hardware by repeatedly interrupting the processor.Since interrupts cannot be recognized during theEI and 01 instructions of the 8085, single step willno t stop at either of these instructions.

Single Step

Pressing the s W key causes the contents of theprogram counter PCH and PCl to be displayedin the address field of the display along with a decimal point at the righ t hand edge of the f ie ld. Thedata field contains the contents of the addressdenoted by the contents of the program counter.The program counter is made available fo r change,and any number entered a number is optionalbecomes the new contents of the program counter.

S W address

Pressing the key causes the CPU to execute theone instruction pointed to by the programcounter. After execution the monitor regains control of the CPU, and the address and data f ie ldsshow the new contents of the program counteraddress of next instruction to execute and contents of the byte addressed by the programcounter, respectively. The decimal point is turnedon at the r ight hand edge of the address field, indicating that the program counter is available again.If the key is pressed, no instruction is executed.The address displayed in the address field is madethe contents of the program counter and the singlestep command is terminated. You may now examine or modi fy registers and memory locations toverify program execution. Pressing the keytakes you back to the single step mode, and subsequent pressing of the key allows you to continue, instruction by instruction, through yourprogram.

4-8


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Vector Interrupt:The key is similar to the 0 key in the respectthat i t takes control away from the monitor andgives it to another program. The interrupt keycauses immediate recognition of RST 7.5 interruptand control passes to location 3C in the monitor.This location contains an unconditional branch toi nst ruction location 20CE in user RAM. You mayplace any instruction you wish in Locations 20CEthru 20DO e.g., a branch to a keyboard interruptroutine . The monitor does not regain control without specific action a 8 command, or a RST 0,RST 1 or JMP 0 program instruction . In branchingback to the monitor, unless the RST 1 instruction isexecuted, the monitor loses all past informationabout the user program.Since an interrupt is recognized by the hardware,the monitor cannot clear the display; thus the display may remain unchanged after interrupt.

IMPORTANT: Two conditions must be satisfiedfor the Vector Interrupt feature to be enabled:1. Interrupts must be enabled by executing an

EI instruction .2. RST 7.5 must be unmasked mask reset by

the SI M inst ruct ion or by modifying the Register .

Program Debugging - The Use of BreakpointsAlong with the cold start reset caused when the8 button is pressed, the monitor also implementsa warm start procedure. Execution of an RST 1instruction will cause the monitor to enter this warm start routine. The monitor will display thesame message as a8 /-80 85 ), but all registersand user memory will be preserved in the state theywere in at the time of execution of the RST 1. Nosystem reset or initialization will be performed.By placing RST 1 instructions at key RAM locations where you want to examine the CPU status,you can break f rom your program and then examine and set memory locations and registers, orsingle-step a portion of your program.

To resume execution of the user program, pressG. The PC value of the next instruction appearsin the address field of the display. Then press to continue execution.Error Condit ions - Illegal KeyIf a key is pressed which is illegal in its contexte.g., a command key is pressed when the monitoris expecting a number , the command is abortedand an error message is generated. Th is messagetakes the form II-Err , displayed in the addressf ield. The monitor is then ready to accept a command. The error message will be cleared when acommand key is pressed. Therefore, you can cancela command before you press or by pressingany illegal key instead.Memory Substitution ErrorsIf the subst itute memory command determinesthat the contents of a memory locat ion were notchanged correctly i .e. locat ion is in ROM or isnonexistent , the command is aborted and an errormessage is generated. This message also takes theform II-Err , displayed in the address f ie ld. Themonitor is then ready to accept a new command.The error message will be cleared when a commandkey is pressed.4-3 TELETYPEWRITER OPERATIONConsole CommandsThis portion of the SDK-85 monitor communicatesvia a teletypewriter console . Operation consistsof dialogue between the operator and the monitorin the monitor s command language. After youpress the 8 button on the SDK-85 keypad, themonitor begins the dialogue by typ ing a sign-onmessage on the console MCS-85 Kit ) and thenrequests a command by typing a prompt character . ). Commands are in the form of a single alphabetic character specifying the command, followedby a list of numeric or alphabetic parameters.Numeric parameters are entered as hexadecimalnumbers. The monitor recognizes the characters 0through 9 and A through F as legal hexadecimaldigi ts. Longer numbers may be entered, but onlythe last four digits will be retained.

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Insert Instructions into RAM I:I Single instructions, or an entire user program, areentered into RAM with the I command. Aftersensing the carriage return terminating the command line, the monitor waits fo r the user to enter a

string of hexadecimal digits to 9, A to F). Eachdigit in the string is converted into its binary value,and then loaded into memory . beginning at thestarting address specified and continuing into se-quential memory locations. Two hexadecimal digitsare loaded into each byte of memory.Separators between digits spaces commas, carriage returns) are ignored; il legal characters, however, will terminate the command with an errormessage see page 4-13). The character ESC or ALTMODE which is echoed to the console as )terminates the digit string.

I COMMAND EXAMPLE 112010112233445566778899This command puts the following pattern intoRAM:2010 2233 44 55 66 77 88 99

I COMMAND EXAMPLE 212040123456789This command puts the following pattern intoRAM:2040 12 34 56 78 90Note that since an odd number of hexadecimal dig its was entered initially a zero wasappended to the digit string.

Move Memory Command, M:M , , The M command moves the contents of memorybetween and inclusive, to the area of RAM beginning at . The contents of the source f ield remainundisturbed, unless the receiving field overlaps thesource field.The move operation is performed on a byte-by-bytebasis beginning at . Care should betaken i f is between and . For example, i f location 2010contains 1A the command M2010, 201 F 2011will result in locations 2010 to 2020 containing1A1A1A , and the original contents of memory will be lost.The monitor wil l continue to move data until thesource field is exhausted, or unt il it reaches addressFFFF. If the monitor reaches FFFF withoutexhausting the source field, i t will move data intothis location, then stop.

M COMMAND EXAMPLEM2010 204F 205064 bytes of memory are moved from 2010204F to 2050-208F by this command.

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Substitute Memory Command, S:S data

The S command allows you to examine and opt iona lly mod ify memory locations individually.The command functions as follows: Type an S followed by the hexadecimal ad-dress of the f irst memory location you wish to

examine, followed by a space or comma.2 The contents of the location are displayed,

followed by a dash - .3 To modify the contents of the location dis

played, type in the new data, followed by aspace, comma, or carriage return. If you dono t wish to modify the location, type onlythe space, comma, or carriage return. Thenext higher memory location will automatically be displayed as in step 2).

4 Type a carriage return. The S command willbe terminated.

S COMMAND EXAMPLES2050 AA- BB-CC 01-13 23-24Locat ion 2050, which contains AA , is un-changed, bu t location 2051 which used tocontain BB) now contains CC 2052 whichused to conta in 01) now contains 13, and2053 which used to contain 23) now contains 24.

Examine/Modify CPU Registers Command, X:x register identifier

Display and modification of the CPU registers isaccomplished via the X command. The X commanduses to select the particularregister to be displayed. A register identifier is asingle alphabetic character denot ing a register,as defined in Table 4-3.

4 2

TABLE 4-3X COMMAND REGISTER IDENTIFIERSIDENTIFIER REGISTERCODE

A Register AB Register BC Register CD Register DE Register EF Flags byteI Interrupt MaskH Register HL Register LM Registers H and L com-

binedS Stack Po interP Program Counter

The command operates as follows:1 Type an X, fol lowed by a register identifier or

a carriage return.2 The contents of the register are displayed two

hexadecimal digits fo r A, B C D, E F, I, H,and L, four hexadecimal digits for M, S P),followed by a dash - .

3 The register may be modif ied at this time bytyping the new value, followed by a space,comma, or carriage return. If no modificationis desired, type only the space, comma, orcarriage return.

4. If a space or comma is typed in step 3), thenext register in sequence will be displayed asin step 2 unless P was just displayed whichcase the command is terminated). If a carriagereturn is entered in step 3, the X command isterm inated.


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If a carriage return is typed in step (1) above,an annotated list of all registers and their contents is displayed.Note: The bits in the flag byte (F) and in ter

rupt mask I are encoded as follows:

The format for the F register:

Error Conditions - Invalid CharactersEach character is checked as i t is entered from theconsole. As soon as the monitor determines thatthe last character entered is illegal in i ts context, itaborts the command and issues an * , , to indicatethe error.

7 o

The format fo r the I register:

INVALID CHARACTER EXAMPLED2000,205G*The character G was encountered in a parameter list where only hexadecimal digits anddelimiters are valid.

7 o

Note: For more information on the 8085 s interrupt masks, please consult the MCS-85User s Manual.

Program Debugging - Breakpoint FacilityThe monitor treats the RST 1 instruction (CF) asa special sequence initiator. Upon execution of anRST 1 instruction the monitor will automaticallysave the complete CPU status and output the signon message MCS-85 Kit to the console. You mayat that t ime display the contents of the CPU statusregister by ini tiat ing an command. Afterexamining the machine status and making anynecessary changes you can resume execution ofthe program by inputting G and Carriage Returnon the console. You can step through large portions of your program by inserting RST 1 instructions at key locations.

Address Value ErrorsSome commands require an address pair of theform , . If , on thesecommands, the value of is greaterthan or equal to the value of , theact ion indicated by the command will be performed on the data at low address only. Addressesare evaluated modu 216. Thus, i f a hexadecimaladdress greater than FFFF is entered, only the last4 hex digits will be used. Another type of addresserror may occur when you specify a part ofmemory in a command which does no t exist in thehardware configuration you are using.In general, if a nonexistent portion of memory isspecified as the source field for an instruction, thedata fetched will be unpredictable. If a nonexistentportion of memory is given as the destination fieldin a command, the command has no effect.

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5 OVERVIEWThis portion of the SDK-85 User's Manual shouldprovide you with sufficient knowledge to writeprograms to exercise the basic system as well asproviding capability to use the basic kit as a nucleus around which you can build larger systems.Figure 5 is a funct ional block diagram of theSDK-85. The components enclosed in dashed boxeshave places in the SDK-85 pr inted circuit board,bu t these are no t needed fo r a minimum systemand are no t included in the kit. In addit ion, somecontrol lines have been om it te d f rom the blockdiagram fo r the sake of simplicity. The full SDK85 schematic diagrams have been included in anappendix fo r your reference.The text to follow describes each of the elementsin the system:

H PTER THE H RDW RE

medium-sized systems. The 8085 multiplexes itsdata bus with the lo w 8 bits of its address bus.The 8155 and 8355/8755 Memory I/ O componentsin the ki t are designed to be compatible with thisbus structure, precluding the need fo r external buslatches.Four vectored interrupt inputs are available inaddition to the standard 8080A-type interrupt.There is also a serial input and serial output datal ine pair that is exercised under program control toprovide the SDK-85's simple teletype I/O.The basic clock frequency of the 8085 in the ki t is3.072 MHz (internally divided by 2 from the 6.144MHz crystal input .

5-2 SYSTEM COMPONENTS The 8155The 8085 CPU The System BusesThe 8085 CPU is an evolutionary enhancement ofIntel's industry standard 8080A. It is 100 software compatible with th e 8080A while offering thebenefits of single power supply, higher integration,higher performance, and improved system timing.The 8085 CPU is fully described in the IntelMCS 85 User's Manual so a detailed descriptionwi II no t be repeated here.As the system block diagram shows, the 8085derives its timing inputs d ir ec tl y f ro m a crystal.In addition the 8085 drives the system with control signals available on-chip. No additional statusdecoding circuitry is required fo r most small- to

The 8155 is a highly integrated chip designed fo rcompatibil ity with the 8085's bus structure. It contains 256 bytes of static RAM memory, 22 programmable I/ O lines, and a 14-b it timer/counter.The function of the 8155 is described in detail inthe Intel MCS-85 User's Manual.One 8155 is included with the SDK-85 ki t andspace fo r another has been provided on the circu itboard. The RA M memory in the 8155 is availablefo r storage of user programs as well as fo r temporary storage of information needed by systemprograms.The 8155's timer is used by the SDK-85 monitor sSingle Step routine to interrupt the processor following the execution of each instruction.

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The 8355 8755 The 8279The 8355 and 8755 are tw o more chips speciallydesigned fo r compatibility with 8085 systems. The8355 contains 2048 bytes of mask programmedread only memory (ROM) and 16 I/ O lines. The8755 has an identical function and pinout to the8355, bu t contains ultraviolet erasable and reprogrammable read only memory (EPROM) instead ofthe ROM.

The 8279 is a keyboard/display controller chipthat handles the interface between the 8085 andthe keypad and LED display on the SDK-85 board.The 8279 refreshes the display from an internalmemory whi le scanning the keyboard to detectkeyboard inputs. The 8279 is described in detailin the MeS-85 User's Manual.The 8205

The SDK-85 contains either one 8355 or one 8755that is programmed with the system monitor.Space fo r a second 8755 or 8355 has been allocatedon the PC board.

The basic SDK-85 also contains an 8205 chip (oneout-of-8 decoder) that decodes the 8085's memoryaddress bits to provide chip enables fo r the 8155,the 8355/8755 and the 8279.

CPU ADDRESSDECODER ROM/IO (8355)EPROM/IO (8755) RAM/IO/COUNTER KEYBOARD DISPLAYADDRESS DATAFIELD FIELD

FOR BUS EXPANSION

DATABUS

8216 I.. ...

r - - - -8212 JPJ

16 ADDRESSBUSr - - - -8212

L..

I I I I ~ - n n.I n /- /- .1I Ct ,=/. C D. D.C/ .I I II SDK-85 KEYBOARD LAYOUTI 1 I I RESET C D E FI I I I SINGLE GO 8 9 A BSTEP H LI I I I rv SUBST EXAM 4 5 6 7MEM REG SPH SPL PCH PCLSERIAL I I I I NEXT EXEC 0 1 2 3 ~ T ~ O I I: DTI : 10 LINES I I D I 74LS156IrD 1 II r ; - . . { r 78755 8155 I I II I 8355 I8085 8205 8155 .II 8279 I I

> I { ;:,. ;>. 1/> I , ; : . . ;: II I I I I I

TA / ' I I I , 7 1 V 71-ESS I I I XBUS I I I I yI I I I rI I I III I I I :I I I I I II I I I I

71 I ? \ ?r

I I I II I I y

ADDR

DAADDR

CONT

INTERRUPTINPUTS

I I I Ir- - OPTIONAL. A PLACE HAS BEEN PROVIDED ON THE PC BOARD FOR T H E D E V I CE B UT T H EL ... DEVICE ISNOT INCLUDED.Figure 5-1 SDK-85 Functional Block Diagram

5-2


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T BLE 5-2MONITOR-RESERVED R M LOCATIONSLOC. CONTENTS20C2 User may place a JMP instr. to a RST 5 routine in ,locs 20C2 - 20C4.20C5 JMP to RST 6 routine Loaded20C8 JMP to RST 6.5 routine hardwired user interrupt) by20CB JMP to RST 7 routine user20CE JIVP to VECT INTR key routine ,

20D1-20E8 Monitor Stack temporary storage used by monitor)20E9 E Register ,20EA D Register20EB C Register20EC B Register20ED Flags20EE A Register20EF L Register > storage fo r user register images20FO H Register20F1 Interrupt Mask20F2 Prog Cntr. - Low byte20F3 Prog Cntr. - HI byte20F4 Stack Ptr. - Low byte20F5 Stack Ptr. - Hi byte20F6 Current Address20F8 urrent Data

20F9-20FC Output buffer Temp Locs20FD Register Pointer20FE Input Buffer20FF 8155 Command/Status Register image

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MEMORY ADDRESS

Please consult the MCS-85 User s Manual fo r theuse of the various special purpose registers referredto in th e table Directio n Registers, Co mma nd /Status Registers, etc.), and for complete instructions fo r exercising the memory-I/O chips (8155/8355/8755).

As was m entioned in the m em ory addressing sec-tion s, t he 8 27 9 is a peripheral chip that is selectedusing memory-mapped I /O. Table 5-4 shows t hetwo memory locations that are used to communicate with the 8279. Consult the MCS-85 User sManual fo r detailed operating instructions.

Accessing the 8279 Keyboard/Display Controller

and drivers in the SDK-85 system structure isshown in Figure 5-1.

Hardware Note: The timer/counter of the first8155 (RAM) is dedicated as a timer. It is hardwiredto receive the 8085 s system clock 3.072 MHzClK) as its count input. This timer is used by thekeyboard monitor s SI NG l STEP function, soyou should beware of timer conflicts if you desireto count and use the SI NG lE STEP function atthe same time. See paragraph 6-2.)

As mentioned before, the 8 15 5 and 8355/8755that come with t he SDK- 85 Ki t have on-boardinput/output ports. These ports are accessed usingthe I N and OUT instructions of th e 80 85 . Eachindividual port being referenced has a unique 8-bitaddress. Table 5-3 contains all the port addressesfor an expanded SDK-85 containing two 8155 sand two 8355/8755 s.

IMPORTANT:As Figure 5-2 indicates, the o pt io na l expansionbuffers leading to the SDK-85 board s prototypingarea are enabled only over the address range8000-FFFF. If you desi re to use any of the OP ENexpansion areas shown in Figure 5-2 enabled bythe 8205 chip selects), you will have to becomefamiliar with the SDK-85 schematics at the backof th is manual and im pl eme nt custom modific ations to the SDK-85 circuitry.

5-4 INPUT/OUTPUT PORTAND PERIPHERALDEVICE ADDRESSING

ACTIVE 8205CHIP ENABLE

~} CS

} CS

} CSl

~

i / OPEN r/

EXPANSION RAM (FOLD BACK)EXPANSION RAM 256 LOC.)

BASIC RAM (FOLD BACK)BASIC RAM(256 LOC.)

1900 - KEYBD/DISPLY CTLRCOMMAND LOC.

1800 - KEYBD/DISPLY CTLRDATA LOC.

OPEN (2K)

EXPANSION ROM (2K)

MONITOR ROM (2K)

180017FF

290028FF

0000

080007FF

30002FFF

1000OFFF

280027FF210020FF20001FFF

I 1EMORY SPACE WHEREEXPANSION BUFFERSI ARE ENABLED r000FFF

Figure 5-2 S DK -85 M em ory MapAny of the areas marked OPEN in Figure 5-2 arefree fo r expansion. You may mount extra memorychips in t he wire-wrap area of the S DK -85 boardor on other circuit boards. The 8205 addressdecoder has 3 uncommitted c hi p select lines toallow the a ddi ti on of three 2 04 8- by te m em or yblocks without additional decoding circuitry.If you want to expand on t he basic SDK-85 youdon t have to stick to the multiplexed-bus MCS 85memory/I/O family. Mounting pads are present onthe circuit board that accommodate an 8212 latchfo r address/data bus demultiplexing. To providethe current drive capabil ity to operate much largersystems, spaces are also allocated fo r another 8212to buffer the unmultiplexed half of the address andfive 8216 buffer/drivers to buffer the data bus, andcontrol signals. The function of these componentsis described in detai l in the 8085 manual. The functional positioning of t he o pt io na l latch, buffers,

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Figure 5-3 Data Format

Figure 5-4 Display Configuration

Example; a would be represented as1 1 1 1 = 99 Hex

SEGMENT

8279 DISPLAYRA M OUTPUT

DESIGNATION

D A TA F IE L DOJ

e

LSB

ADDRESS FIELD

af l b~ ~d p

TABLE 5-4ACCESSING THE 8279KEYBOARD DISPLAY CONTROLLER

e a p

LOCATION READ FUNCTIONWRITE1800 Read Read KeyboardFIFO

Write Write Data toDisplay1900 Read Read StatusWord

Write Write CommandWord

MSB

These are six active LED displays available fo r useThey are configured in a four-place address fieldand a two-place data field as in Figure 5-4.

The hardware is designed so that writing a zero intoa bi t position turns on the corresponding LEDsegment.

TABLE 5-3SDK-85 I O PORT MAP

The data format fo r character bytes being displayed by the 8279 is one bi t corresponding toeach of the seven LE D segments plus one b it fo rthe decimal point. Figure 5-3 shows the bi tconfiguration.

PORT FUNCTION00 Monitor ROM PORT A 1 Monitor ROM PORT B02 Monitor ROM PORT AData Direction Register03 Monitor ROM PORT BData Direction Register08 Expansion ROM PO RT A09 Expansion ROM PO RT BOA Expansion ROM PO RT AData Direction RegisterOB Expansion ROM PO RT BData Direction Register20 BASIC RAM COMMAND/STATUSRegister21 BASIC RAM PORT A22 BASIC RAM PORT B23 BASIC RAM PORT C24 BASI C RAM Low Order Byte

of Timer Cou nt25 BASIC RAM High Order Byte

of Timer Cou nt28 EXPANSION RAM

COM MAN D/STATUS Register29 EXPANSION RAM PORT A2A EXPANSION RAM PORT B2B EXPANSION RAM PORT C2C EXPANSION RAM Low Order Byte

of Timer Cou nt2D EXPANSION RAM High Order Byte

of Timer Cou nt

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The display digi ts are stored within the 8279 display RAM in the locations listed in Table 5-5.

5 6 THE SERI L D TINTERF E

8279 DISPLAY RAMLOCATION PURP S

0 Address digit 11 22

Data Digit 15 26 UNUSED7 UNUSED

5 5

TABLE 5-5

PRO SSOR INT RRUPTLLO TION

The SDK-85 has the capability of communicatingwith a teletype, using the 8085 serial input andserial output data lines Sl D and SOD respectivelyto send and receive the serial bit strings that encodedata characters.To send data to the teletype, the 8085 must togglethe SOD line in a set/reset fashion controlled bysoftware timing routines in the SDK-85 monitor.Input data is obtained by monitor ing and timingchanges in the level of the Sl D pin. Again, a monito r routine is called upon to do the job.These teletype communications routines are acces-sible to the user.Both subroutines communicate at a data rate of110 baud, the standard rate for teletypewriters.

The 8085 has four Vector Interrupt input pins inaddition to an 8080A compatible interrupt input.The name of each interrupt and its function in theSDK-85 hardware is l isted in Table 5-6.The function of the on-chip interrupts is describedin detai l in the 8085 Manual.

TABLE 5-68 85 ON CHIP INTERRUPT ALLOCATIONINPUT FUNCTIONRST 5.5 Ded icated to 8279RST 6.5 Avai lable User InterruptRST 7.5 ll button interruptTRAP 55 Ti mer InterruptINTR Available User Interrupt

Since the 8085 serial input and output l ines aredesigned fo r communicating with other integratedcircuits, addit ional electronic circuitry is neededbefore they can be connected to a terminal . TheTTY interface in the top right corner of the boardallows the SDK-85 to be connected to any teletype that uses 20 mA current loop input andoutput.

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5-7 CONVERTER CIRCUIT FORRS232C SERIAL PORTIf you are fortunate enough to have a CRT terminal that can operate at a 110-baud rate, and wishto use it with the SDK-85 computer, you mayfind that it is compatible only with RS 3 cvoltage-level serial por ts and not with currentloops. If this is the caseo Wire the MC1488 and MC1489 converter

circuit shown in Figure 5-5) into the wirewrap area of the SDK-85 board.o Remove R6, and connect the input line ofthe converter circuit to its lower pad. Youcould put a switch in this line if you wantedto.)o Open both the TTY and KEYBOARD jump

ers and connect the output line of the converter to the midd le pad, which is strapping+5V

14

point 23. I f you are using a switch, one witha center off position could be used.)o Connect your CRT as shown in Figure 5-5.o Connect the 3 different voltages to thecircuit.

5-8 ADDITIONAL INTERFACESAdditional interface considerations are discussed inIntel Application Note AP-29, which also describesa low-cost cassette tape-recorder interface, thatcan be added to your SO K-85 kit. AP-29 can beordered by sending 1.00to: Literature Department,Intel Corp., 3065 Bowers Ave., Santa Clara, Ca.95051.

SID

8085

JUMPERPIN 23

11REMOVE .---+--fR69

J >


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6-1 THE SDK-85 MONITORThe SDK-85 monitor program provides utilityfunctions e mp lo yi ng e it he r a teletypewriter or thekit s o n- boa rd ke ybo ar d and d isp la y as console.The program resides in 2k (k = 1024) bytes of theROM memory, between location 0 and location7 FF. t he r ou ti ne s that service each console de-vice are independent; the two devices do not function simultaneously. You may select either thekeyboard and display or the teletypewriter as theconsole device by actuating a switch (not furnished)or by changing strapping connections. Both can beused to perform substantially the same tasks. SeeChapter 4.)

6-2 PROGRAMMING HINTSStack PointerThe 8085 makes use of a 16-bit internal registercalled t he Stack Pointer to point to an area ofmemory called the stack. The 8085 s stack isused for saving many things, such as memoryaddresses for returns from subroutines.It is important always to define the stack pointerat the beginning of your program to avoid storingdata in the wr ong place. Locations 20C2 th ro ug h2000 in RAM are reserved by the monitor forjump i nst ru ct ion s when all interrupts are used.Thus, y ou should set t he stack pointer initial ly at20C2 by the use of t he program i ns tr uc ti onLXI SP 20C2H 31 C2 20), the keyboard command

[;1J 20) C2) EJ or the teletypewriterXS co mm and ) i n o rd er to keep your own stackclear of data and programs you want to protect.I f less than the full complement of interrupts is

CH PTERTHE SOFTWARE

uti lized, some or all of the unused space above20C2 can be allocated to stack as described above.Remember that t he stack mus t s ti ll oc cu py an unbroken string of contiguous memory locations.RAM-I/O Command Status Register CSR)The basic 8155 command status register (port 20)is used to set u p t he on-chip I/O p or ts and t im er .It can only be written to ; it cannot be read. Youcan write to t hi s register in your programs, butthere is a precaution y ou should take: a t any timewhen you write to the CSR in t he basic RA M, youshould also write the same pattern to RAM location20FF. The reason is this: The ~ ~ ~ ~ command causesthe monitor to change the CSR in order to setup the timer for execution of the command. I f itis not told what value you previously put t he re b ysaving the value in 20FF), that value will inevitablybe overwritten and lost. Following each single step,the monitor reads location 20FF, logically DRs itstimer command to the content of that location, andwrites t he CSR with t he new command, th er eb yretrieving your previous configuration.Access to Monitor RoutinesYou may borrow several of the SDK-85 monitorroutines to simpli fy your programming task. Table6-1 provides descriptions and calling addresses forthese routines.6-3 PROGRAMMING EXAMPLESThe programming examples presented at the end ofthis chapter demonstrate how to use the monitorroutines to operate the keyboard and display.

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TABLE 6 1MONITOR ROUTINE CALLING ADDRESSES

6

Calling Address07FD

07FA

05EB

06C7

0363

036E

02E7

05F1

MnemonicCI

co

CROUT

NMOUT

UPDAD

UPDDT

RDKBD

DELAY

DescriptionConsole InputThis routine returns a character in ASCII code - see 8 85 8 8reference card fo r codes received from the teletype to the callerin the A register. The A register and CPU condition codes areaffected by this operationConsole OutputThis routine transmits a character in ASCII code , passed fromthe caller in the C register, to the teletypewr iter . The A and Cregisters, and the CPU condition codes are affected.Carriage Return, Line FeedCROUT sends carriage return and line feed characters to theteletype. The contents of the A B and C registers are destroyedand the CPU condition codes are affected.Hex Number PrinterNMOUT converts the 8 bit unsigned integer in the A register into2 ASCII characters representing the 2 hex digits and prints thetwo digits on the teletypewriter. The contents of the A, Band Cregisters and the condition code flags are affected.Update AddressUpdate address field of the display. The contents of the D Eregister pair are displayed in the address field of the display.The contents of all the CPU registers and flags are affected.Update DataUpdate data field of the display. The contents of the A registerare displayed in hex notation in the data f ie ld of the display.The contents of all of the CPU registers and flags are affected.Read KeyboardThis routine waits until a character is entered on the hex keypadand upon return places the value of the character in the A regis-ter. The A, H and L registers and the flag flip flops are affected.NOTE: For RDKBD to work correct ly, you must f irst :1 Unmask RST 5.5 using the SIM instruction.Time DelayThis routine takes the 16-bit contents of register pair DE andcounts down to zero, then returns to the calling program. TheA, D and E registers and the flags are affected.


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TABLE 6 1MONITOR ROUTINE CALLING ADDRESSES CONT D)

Calling Address B7

MnemonicOUTPT

DescriptionOutput Characters to DisplayThe routine sends characters to the display with the parametersset up by registers A, B Hand LReg A = 0 = use address field

= 1 = use data fieldReg B = 0 = decimal point off

= 1 = decimal point at r ight edge of fieldReg HL = starting address of characters to to sent

CharacterDisplayedo23456789AbCdEFHLPIrSBlank

Hexadecimal memorycontent pointed to

by the HL register0123456789OOOCOEOF101121314515

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PROGRAM EXAMPLE RDKBDAfter executing 2 the program waits until a key is pressed Then the value of the key is placedin the A register and the monitor is restarted. Use to see that the key value is now in the A register.

ADDRESS T SYMBOLIC2000 31 LX I SP 20C2H2001 C22002 202003 3E MVI A 08H2004 082005 3 SIM2006 CD CALL RDKBD2007 E72008 022009 CF RST 1

COMMENTS; define stack pointer

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