®

© 2000 Burr-Brown Corporation LI-548 Printed in U.S.A. March, 2000

DEM-ADS7870DATA ACQUISITION SYSTEM

FEATURES EASY INSTALLATION AND USE

WINDOWS® BASED GRAPHICAL USERINTERFACE

SAMPLE EXCITATION SIGNALSGENERATED ON-BOARD

BUILT-IN 9V BATTERY POWER OREXTERNAL POWER

FAST SERIAL DIGITAL INTERFACE

INTERACTIVE DEVICE REGISTERCONFIGURATION

SAVE 64 POINT DATA SET TO DISK FILE

DESCRIPTIONThe DEM-ADS7870 is a demonstration fixture thatallows for easy evaluation of the ADS7870 low-powerdata- acquisition system on a single chip. On-boardstimulus generation is provided to demonstrate severalADS7870 functions. The card can also be configuredto digitize external signals.

Software provided with the DEM-ADS7870 runs un-der Windows 95 or 98 only, on an IBM compatiblePC. The software can be quickly “installed”. The userinterface can set all of the configuration variableswithin the ADS7870 as well as select various stimulussignals.

Power for the DEM-ADS7870 can be derived from theon-board 9V battery or from an external supply of atleast 8VDC.

International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate P roduct Info: (800) 548-6132

SBAU005

2®

DEM-ADS7870

JUMPER DEFAULT FUNCTION

P1 EXT Power Source

P2 1-2 VREF/BUF_IN Select

P3 Open Configuration U2

P4 Open Configuration U2

P5, P6, P7 5-6 DIO Select

P8 1-2 CCLK Source

P9, P10, P11 9-10 Signal Source

P12 1-2 LED0

P13 1-2 LED1

P14 1-2 LED2

P15 1-2 LED3

P16 Open Stimulus Programming Port

TEST POINT SIGNAL

E1 Interface Logic

E2 VREF Input

E3-E8 Ground Points

TABLE II. Test Point Description.

TABLE I. Configuration Jumpers with Default Factory Settings.

HARDWARE SET-UPThe DEM-ADS7870 uses two embedded “PIC” controllers.The configuration jumpers are set in the manner described inTable I.

An initial demonstration can be run by simply installing a9V battery and moving the P1 jumper to the BAT position.Jumper configurations can be changed later to show otherfeatures.

The test points on the E1 header allow monitoring of the dig-ital interface signals between the DUT and the host controller.

SOFTWARE INSTALLATIONUser-interface software is installed in the normal Windowsmanner. Close all other applications. From the “Start” buttonon the task-bar select “Run”. In the window that opens, type:

d:\ setup

Where: “d” is the letter designation of the CD-ROMdrive on the computer.

Follow the prompts to install the software.

To run the program, left-click on “Start” from the task-barand then expand the “Programs” menu. The applicationprogram is titled “Burr-Brown ADS7870 Application”.

To remove this application, use the Control Panel “Add/Remove software” utility, in the Windows system.

APPLICATION SOFTWAREOPERATIONFigure 1 shows the opening window of the application withthe data display inner window. The system status is dis-played in the banner of the data display window. To config-ure the communications section, activate the “Setup” pull-down and select “Communications Setup”. From this dialogbox select the appropriate COMx port. When communica-tion is established, the word “Disconnected” will change to“Connected”.

Once communication is established, left-click the “Start”

FIGURE 1. Opening Screen from the Burr-Brown ADS7870 Application Program.

3®

DEM-ADS7870

button to get the display as shown in Figure 2. The sine wavegenerator is not synchronized with the conversions of theADS7870, so each data set may start at a different point inthe waveform.

ON-BOARD STIMULUS OPTIONS

FIGURE 2. Typical Data Display with Default Configuration.

From the top menu bar open the “Setup” menu and thenselect “Inputs”. A window, as shown in Figure 3, will bepresented. From this window, it is possible to select thesignal to be digitized and change the relevant register con-tents that configure the ADS7870.

The C-Clock Divisor panel in the lower right hand corner of

FIGURE 3. Setup...Inputs... Screen Start-up Default Values.

the Inputs window must be set to 8 when the device isoperated with the on-board oscillator.

An internally generated signal can be selected from theWaveform pull down menu, as shown in Figure 4.

To digitize a complex waveform, select two sine waves,

FIGURE 4. Waveform Selections.

4®

DEM-ADS7870

setting Freq 1=0.82 and Freq 2 =4.01 for a ratio of 5:1. Theresult is shown in Figure 5.

In Figure 5, there is a box drawn around the waveform. Thisis a zoom window. Place the cursor just to the left of the firstdata point. Holding the left mouse button down, draw a boxas shown. The result of the zoom operation is shown inFigure 6, below.

Acquisition of a DC voltage can also be demonstrated by

A/D conversion should be very close to the first value noted.Reset the Channel Input Configuration to Differential,–LN2+LN3, close the window and collect another data set.The A/D conversion value displayed will be the two’scompliment of the first readings.

To demonstrate the PGA over-range flag, return the configu-ration to the Internal Source stimulus and increase the PGAgain to 20 on the Setup...Inputs control screen. Starting adata collection sequence will result in a display, as shown inFigure 7.

VIEW PULL-DOWN MENU

FIGURE 5. Two Sine Waves.

FIGURE 6. Two Sine Wave Trace After Zoom Operation.

selecting that option from the Internal Stimulus, ...Wave-form menu, and then setting a voltage level by entering avalue between 0 and 16,383. This is useful in demonstratingthe treatment of negative numbers by the ADS7870.

Open the Setup...Inputs screen and set the Waveform DC atsome non-zero value. Execute a data collection sequenceand, using the View Register Values as described below,note the hex code of the last A/D conversion. Through theSetup...Inputs screen, change the stimulus to External Sources,but do not move any jumpers. Select Channel Input Configu-ration to Differential, +LN2–LN3. Close the window andexecute a data collection. The value of the last

FIGURE 7. PGA Overload. Note that the number of valid datapoints will vary depending on the level of the sinewave at the time the data set is collected.

The internal configuration registers of the ADS7870 can beexamined with the View...Register Values, as shown inFigure 8.

The individual bits may be examined and changed where

FIGURE 8. Register Values.

valid, with the pull-down menu View...Register Details.Examples of these screens are given in the following fivefigures.

The contents of register 2 shown in Figure 9 report that there

5®

DEM-ADS7870

was a positive over range signal at the output of the PGA.

To move from one display to another, click on the top tab.To change a bit, place the mouse arrow in the window anddouble left click. The resulting HEX value for that registerwill be displayed on the right and the operational effect ofthe change will be displayed in the label block.

The values will be written to the ADS7870 on “Update” or“Close” of the window.

APPENDIX A: DEMO BOARD

FIGURE 9. Read-Only Registers 0, 1, and 2.

FIGURE 10. ADS7870 Configuration Registers. See theproduct data sheet for detailed description ofthe functions available.

FIGURE 11. Device Status in Register 5 and Control of theDIO Lines.

FIGURE 12. Communication Configuration Bits. This settingis necessary to work with the on-board PICcontroller.

FIGURE 13. Revision Code for the Device is Displayed in thisRegister.

6®

DEM-ADS7870

CONSTRUCTION DETAILSCIRCUIT DIAGRAM AND PC BOARD

The circuit diagram is presented in three sections. Figure 14 covers the RS232 communications through to the ADS7870.Figure 15 depicts the on-board stimulus generator. Figure 16 shows the interconnect between the sections and the powersupply.

Figures 17 through 21 show the artwork for the four-layer PCB and top silk screen. Table III is the bill of material for the entireassembly.

ITEM QTY REFDES MAKE Part Number VALUE PACKAGE DIGIKEY

1 1 B1 KEYSTONE 1294K BH9V-1 1294K2 3 C1, C12, C14 PANASONIC ECS-T1AX106R 10µF 3528 PCS2106CT3 5 C2, C4, C8, C13, C19 PANASONIC ECU-V1H104KBW 0.1µF CC1206 PCC104BCT4 1 C3 PANASONIC ECU-V1H103KBG 0.01µF CC0805 PCC103BNCT5 4 C5, C6, C10, C11 PANASONIC ECU-V1H220JCV 22pF CC0603 PCC220ACVCT6 5 C7, C9, C15, C16, C18 PANASONIC ECS-T1EY474R 0.47µF 3216 PCS5474CT7 1 C17 PANASONIC ECU-V1H121JCV 120pF CC0603 PCC121ACVCT8 2 D1, D2 LITEON LLSD103A LLSD103A MLL34 LLSD103ACT9 4 D3, D4, D5, D6 CHICAGO_MLI CMD91-21VRC/TR7 — CMD91-21 L62901CT

10 1 D7 DIODES ZMM5232B 5.6V MLL34 ZMM5232BCT11 5 E1, P5, P6, P7, P16 NORCOMP 2163-08-01-P2 — HDR8/2MM-1 2163S-0812 7 E2, E3, E4, E5, E6, E7, E8 NORCOMP 2163-01-01-P2 — EPOINT-M 2163S-0113 1 J1 OST ED555/2DS — ED555/2DS ED151414 1 J2 AMP 520250-2 — AM6-520250 —15 1 J3 OST ED555/16DS — ED555/16DS ED152616 7 P1, P3, P4, P12, P13, P14, P15 NORCOMP 2163-03-01-P2 — HDR3/2MM-1 2163S-0317 2 P2, P8 NORCOMP 2163-02-01-P2 — HDR2/2MM-1 2163S-0218 3 P9, P10, P11 NORCOMP 2163-06-01-P2 — HDR6/2MM-1 2163S-0619 1 R1 PANASONIC ERJ-6ENF4752V 47.5k CR0805 P47.5KCTR20 3 R2, R4, R5 PANASONIC ERJ-6ENF2002V 20.0k CR0805 P20.0KCTR21 2 R3, R13 PANASONIC ERJ-6ENF4022V 40.2k CR0805 P40.2KCTR22 5 R6, R7, R8, R9, R10 PANASONIC ERJ-6ENF3011V 3.01k CR0805 P3.01KCTR23 1 R11 PANASONIC ERJ-6ENF1823V 182k CR0805 P182KCTR24 1 R12 PANASONIC ERJ-6ENF10R0V 10 CR0805 P10.0CTR25 1 U1 NATIONAL LM2936M-5.0 — SO8 —26 1 U2 MICROCHIP PIC16C63-20/JW — DIP28-300 PIC16C63/JW27 1 U3 BURR-BROWN ADS7870 — SSOP28 —28 1 U4 MAXIM MAX3320LCAP — SSO20 —29 1 U5 MICROCHIP PIC16F84-10/SO — SO18W PIC16F84-10/SO30 1 U6 BI_TECH 628L104TR — SO16RP —31 1 Y1 ECS ECS-200-20-4 20.000MHz XTALV X43932 1 Y2 ECS ECS-100-S-4 10.000MHz XTALV X42233 1 — — — PCB — —34 1 — MILL-MAX 115-93-328-41-001 Socket, 28-pin, 300 mil for U2 — ED5828335 7 — Specialty Elect 2JM-G Jumper shunt, 2mm — SPE130236 1 — Comm Con MIJ2MM-06 Jumper shunt block, 2mm, 2 x 6 — —37 1 — Comm Con MIJ2MM-08 Jumper shunt block, 2mm, 2 x 8 — —38 4 — — — Mounting pins - battery clip — —39 1 — — — Serial cable per drawing — —

TABLE III. Parts List.

7®

DEM-ADS7870

20 18 2 3 11 12 16 15 14 13

R5

20.0

kΩ

R4

20.0

kΩ

+5V

2 3 4 5

RS

-232

PO

RT

J252

020-

2

AC

Q_D

AT

A_O

UT

AC

Q_C

NT

RL_

IN

C1+

C1–

C2+

C2–

FO

RC

EO

FF

FO

RC

EO

N

T1_

OU

T

T2_

OU

T

R1_

IN

R2_

IN

1 4 10 9 5 6 7 8

V+

V–

RE

SE

T

INV

ALI

D

T1_

IN

T2_

IN

R1_

OU

T

R2_

OU

T

U4

MA

X33

20

C13

0.1µ

F

9 10 1 27 28 2 3 4 5 6 7

OS

C1_

CLK

IN

OS

C2_

CLK

OU

T

MC

LR_V

PP

RB

6_P

CLK

RB

7_P

DA

TA

RA

0

RA

1

RA

2

RA

3

RA

4

RA

5

+5V

: 20,

GN

D: 8

, 19

RS

-232

to S

PI

Con

trol

ler

+5V

: 19,

GN

D: 1

7

21 22 23 24 25 26 11 12 13 14 15 16 17 18

RB

0

RB

1

RB

2

RB

3

RB

4

RB

5

RC

0

RC

1

RC

2

RC

3_S

CK

RC

4_S

DI

RC

5_S

DO

RC

6_T

X

RC

7_R

X

U2

PIC

16C

63

9 10 23 20 21 22 18 19 16 17 26 27 28 15

RE

SE

T

RIS

E/F

ALL

CS

SC

LK

DIN

DO

UT

OS

C_C

TR

L

CC

LK

CO

NV

ER

T

BU

SY

VR

EF

BU

FIN

BU

FO

UT

/RE

FIN

NC

+5V

: 24,

GN

D: 2

5

11 12 13 14 1 2 3 4 5 6 7 8

DIO

0

DIO

1

DIO

2

DIO

3

LN0

LN1

LN2

LN3

LN4

LN5

LN6

LN7

U3

AD

S78

70

AC

QU

ISIT

ION

CH

IP

C15

0.47

µF+

+5V

+

C5

22pF

C6

22pF

Y1

20M

Hz

C9

0.47

µF

+C

180.

47µF

P3

P4

P8

P2CC

LK

AD

S_R

ES

ET

RIS

E_F

ALL

_N

CO

NV

ER

T

BU

SY

CS

_N

OS

C_C

NT

RL

ST

IM_R

ST

_N

SC

K

SD

I

SD

O

VR

EF

BU

FIN

+5V

CO

M_O

SC

1

CO

M_O

SC

2 SE

L0

SE

L1

P10

HD

R

P6

HD

R

1 2 3 4 5 6 1 2 3 4 5 6 7 8

D3

P12

R6

3.01

kΩ

D4

P13

R7

3.01

kΩ

D5

P14

R8

3.01

kΩ

D6

P15

R9

3.01

kΩ

C3

0.01

µFC

70.

47µF

R1

47.5

kΩ

BU

FO

UT

+5V

FIGURE 14.

8®

DEM-ADS7870

15 16 4 17 18 1 2 3

OS

C1_

CLK

IN

OS

C2_

CLK

OU

T

MC

LR_V

PP

RA

0

RA

1

RA

2

RA

3

RA

4

+5V

: 14,

GN

D: 5

6 7 8 9 10 11 12 13 14

RB

0

RB

1

RB

2

RB

3

RB

4

RB

5

RB

6

RB

7

+V

U5

PIC

16F

84

Stim

ulus

Gen

erat

or

1 2 3 4 5 6 7 8

Stim

ulus

Pro

gram

Por

t

P16

HD

R

+5V

C10

22pF

C11

22pF

Y2

10M

Hz

C17

120p

FR

220

kΩ

R11

182k

Ω

C14

10µF

+R

1340

.2kΩ

R3

40.2

kΩ

10kΩ

20kΩ

1 2 3 4 5 6 7 8

16 15 14 13 12 11 10 9

10kΩ

20kΩ

10kΩ

20kΩ

10kΩ

20kΩ

10kΩ

20kΩ

10kΩ

20kΩ

10kΩ

20kΩ

20kΩ

20kΩ

R10

301k

Ω

D2

D7

5.6V

1 2 3 4 5 6

P9

HD

R

ST

IM_D

IO0ST

IM_W

AV

E

ST

IM_L

EV

EL

ST

IM_R

ES

ET

_N

ST

IM_P

WM

ST

IM_D

IO (

3.0)

ST

IM_+

5V

DA

C0

ST

IM_O

SC

1

ST

IM_O

SC

1

ST

IM_D

IO1

ST

IM_D

IO2

ST

IM_D

IO3

ST

IM_D

IO0

PR

OG

_VP

P

PR

OG

_CLK

PR

OG

_DA

TA

DA

C1

DA

C2

DA

C3

DA

C4

DA

C5

DA

C6

DA

C7

C19

0.1µ

F

ST

IM_D

IO1

ST

IM_D

IO2

ST

IM_D

IO3

1 2 3 4 5 6 7 8

P5

HD

R

62B

L104

FIGURE 15.

9®

DEM-ADS7870

FIGURE 16.

1 2

Ter

m 1

Ter

m 2

Ext

erna

l9

VD

CP

ower

J1T

ER

M B

LK

9V_I

N

DC

_IN

1 2

B+

B–

B1

9V B

AT

P1

1 3

2P

WR

_IN

D1

RE

G_I

N

1 2 3 4 5 6

U5-

14

R10

-D2

U5-

3

U5-

18

U5-

1

U5-

2

ST

IM_+

5V

ST

IM_R

ES

ET

-N

ST

IM_D

IO0

ST

IM_D

IO1

ST

IM_D

IO2

ST

IM_D

IO3

C17

-R2

C14

-R13

ST

IM_W

AV

E

ST

IM_L

EV

EL

P9

HD

R

U3-

11

U3-

12

U3-

13

U3-

14

U3-

24

U3-

25D

IO0

DIO

1

DIO

2

DIO

3

+5V

I_M

ON

ST

IM_R

SC

NU

2-13

BU

FO

UT

U3-

28

U3-

1

U3-

2

U3-

3

U3-

4

U3-

5

U3-

6

U3-

7

U3-

8

LN0

LN1

LN2

LN3

LN4

LN5

LN6

LN7

1 2 3 4 5 6 7 8

P5

HD

R

1 2 3 4 5 6

P10

HD

R

AC

QU

ISIT

ION

SE

LEC

T

Stim

ulus

Ext

erna

l

+5V

DIO

0

DIO

1

DIO

2

DIO

3

LN0

LN1

LN2

LN3

LN4

LN5

LN6

LN7

1 2 3 4 5 6 7 8

P6

HD

R

+5V

1 2 3 4 5 6

P11

HD

R

1 2 3 4 5 6 7 8

P7

HD

R

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

EX

T_D

IO0

EX

T_D

IO1

EX

T_D

IO2

EX

T_D

IO3

EX

T_L

N0

EX

T_L

N1

EX

T_L

N2

EX

T_L

N3

EX

T_L

N4

EX

T_L

N5

EX

T_L

N6

EX

T_L

N7

Ter

m1

Ter

m2

Ter

m3

Ter

m4

Ter

m5

Ter

m6

Ter

m7

Ter

m8

Ter

m9

Ter

m10

Ter

m11

Ter

m12

Ter

m13

Ter

m14

Ter

m15

Ter

m16J3

TE

RM

BLK

Ext

erna

l Sig

nal

Ter

min

al B

lock

E3

GN

D

1

E4

Tes

t Gro

unds

GN

D

1

E5

GN

D

1

E6

GN

D

1

E7

GN

D

1

E8

GN

D

1

C2

0.1µ

FC

110

µF

8 2 3 6 7

VIN

GN

D1

GN

D2

GN

D3

GN

D4U

1LM

2936

M-5

1

+

5.0V

+5V

C8

0.1µ

F

R12

10.0

Ω

C12

10µF

+

+5V

10®

DEM-ADS7870

FIGURE 17. Top Layer.

FIGURE 18. Ground Plane.

FIGURE 19. Power Plane.

11®

DEM-ADS7870

FIGURE 21. Top Side (Silkscreen).

FIGURE 20. Bottom Side.

12®

DEM-ADS7870

APPENDIX B: EMBEDDEDMICRO-CONTROLLERPROGRAMMINGThe embedded controllers can be reprogrammed. The sourcecode for each of the devices is provided in the CD in thefolder titled Support. The files associated with U2, thePIC16C63 are titled “adcmain”.

A PIC16F84 generates the on-board signals. Source codefiles associated with this device contain “stimgen” in thename. Program memory in this device is flash memory andcan be reprogrammed.

PROGRAMMING THE STIMULUS GENERATOR

The DEM-ADS7870 stimulus generator, a MicrochipPIC16F84, is programmed on board through P16, a 2mmspaced 8-pin header. Since only four connections are needed,it is easy to create an adapter for a socket programmer, such asthe PICStart Plus. A diagram of the adapter is shown below.

PIC16F84 PROGRAMMING ADAPTER

The adapter consists of the following parts:1) One 18-pin solder tail DIP socket, DigiKey ED3318 or

equivalent.

2) One 8-pin 2mm solder tail SIP socket, DigiKey 2063S-08or equivalent.

3) Four 10" long pieces of AWG 26 stranded insulatedhookup wire.

4) Small heat shrink tubing.

5) Small wire ties.

To construct the programming adapter:1) Strip and tin the ends of the wires.

2) Slide 3/4" lengths of heat shrink tubing onto the wires.3) Solder the 10" wires to the following points.

SIP socket pin 4 solder tail to DIP socket pin 4 top side.SIP socket pin 5 solder tail to DIP socket pin 12 top side.SIP socket pin 6 solder tail to DIP socket pin 13 top side.SIP socket pin 8 solder tail to DIP socket pin 5 top side.

4) Shrink the heat shrink tubing over the header pin connec-tions.

5) Tie the wires for support.6) Fill pin 2 of the SIP header with epoxy for keying.

(If you plug this in wrong you may blow up the PIC.)

FIGURE 22.

44

5

6

8

2AWG 26 WIRE - 10"

5 13

12

IMPORTANT NOTICE

Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinueany product or service without notice, and advise customers to obtain the latest version of relevant informationto verify, before placing orders, that information being relied on is current and complete. All products are soldsubject to the terms and conditions of sale supplied at the time of order acknowledgment, including thosepertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its semiconductor products to the specifications applicable at the time of sale inaccordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extentTI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarilyperformed, except those mandated by government requirements.

Customers are responsible for their applications using TI components.

In order to minimize risks associated with the customer’s applications, adequate design and operatingsafeguards must be provided by the customer to minimize inherent or procedural hazards.

TI assumes no liability for applications assistance or customer product design. TI does not warrant or representthat any license, either express or implied, is granted under any patent right, copyright, mask work right, or otherintellectual property right of TI covering or relating to any combination, machine, or process in which suchsemiconductor products or services might be or are used. TI’s publication of information regarding any thirdparty’s products or services does not constitute TI’s approval, warranty or endorsement thereof.

Copyright 2000, Texas Instruments Incorporated