1.Basic Digital Concepts Port OR Out Put of a Digital Circuit 5 Volt Pin of IC 1 at this O/P =5V with 30mA source 0 at this O/P = 0V with 30 mA sink GND pin of IC +ve of 5V -ve of 5V 150ohm 150ohm

2. Decimal Binary Hexadecimal 10 11 12 13 14 15 3 4 5 6 7 8 9 2 1 0 1 1 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 1 1 0 1 0 0 0 1 0 1 0 1 1 1 0 1 1 0 1 0 0 0 1 0 0 1 1 0 1 0 1 1 0 0 1 0 1 1 1 1 0 1 1 1 1 0 1 3 4 5 6 7 8 9 2 1 0 A B C D E F 1 0 1 0 0 1 0 1 0 4A 4 A 3. 1 0 0 1 0 0 1 @ Registers are memory locations inside the controller. @ It can store an 8 bit binary @ It can do some operation on this binary word. A Port of Microcontroller Register While writing the register content to the port (MOV port, register) 5V 0V 0V 5V 0V 5V 5V 0V 1 0 1 1 1 0 1 0 0 4. A --- The accumulator to do all arithmetic and logic operation. B ---- B register. R0 -R7 --- 8 general purpose registers. PC ---- Program counter. DPTR --- Data pointer. Interrupt register and SFRs. 5. INTERNAL RAM User Ram Register bank Bit addressable Ram r5 r4 r3 r2r6 r1 r0r7 00 7F B0B7 R2 If r2=3C 1 0 10 0 00 1 07 80 TO FF are SFRs 6. INTERNAL RAM User Ram Register bank Bit addressable Ram r5 r4 r3 r2r6 r1 r0r7 00 7F B0B7 R2 If r2=3C 1 0 10 0 00 1 07 7. PROGRAM MEMORY. 0000 0001 0002 3F12 3F13 3F14 FFFF EXTERNAL Total 64 K Bytes INTERNAL Total 4K Bytes. 000 FFF 8. 1 Commands are binary words. 2. Each command has a specific work. 3. This work is done on MEMORY, REGISTERS, or PORTS. 4. These commands are stored in PROGRAM MEMORY. 5. Controller will read these commands from program memory and execute. 6. The result of one command will not be changed until the execution of another command at the same destination. 9. How controller works. MOV A,r0 ADD A,#0B Programmemory 1 0 1 0 1 1 1 0 r0 A Reading command OR Fetch cycle DATA BUS 3F14 3F13 3F12 Decoding commands EXECUTING Program counter 3F123F13 0 0 1 1 1 1 1 0 MOV A,r0 ADD A,#0B 3F14 Addressbus AddressofP.G 1 0 1 1 0 0 0 0 0 1 0 0 0 1 1 0 10. JUMP INSTRUCTION LJMP and SJMP are used to Change the flow of commands. L JMP 3A20 ADD B,#F3ADD B,#F3 MOV P2,A MOV A,r1 1F00 1F01 1F02 3A20 3A21 3A22 1F001F01 3A20 1F02 Program counter Program memory 11. CALL Instruction LCALL A018 MOV A,P2 vv LCALL A108 RRA RRA RRA RRA MOV A,@R1 Program Counter A10 8A109 A10A 2101 2102 2100 02CA 02CB A10B A10C 02CC 02CA 2100 02CB 2101 A108 07 Stack Pointer. 07 08 0B 0A 09 STACKRETA10D 0708 12. 1. Addressing is to which or where OR from which or where the command should act. eg: ADD A,#0B a. A is the address where the ADD should act. (Register addressing) b. #0B is not an address. But this method is immediate addressing. 13. Expressions used in Instruction Set and Addressing Modes Rn:---- Register R7-R0 direct :------8-bit internal RAM address. location (0-127) or a SFR @Ri :-----8-bit internal data RAM location (0-255) addressed indirectly through register R1or R0. #data :------8-bit constant included in instruction. #data 16:------ 16-bit constant included in instruction. 14. Expressions used in Instruction Set and Addressing Modes addr 16 :-------16-bit address. Used by LCALL and LJMP. A branch can be anywhere within the 64K byte Program Memory address space. addr 11:------- 11-bit destination address. Used by ACALL and AJMP. The branch will be within the same 2K byte page of program memory as the first byte of the following instruction. rel :------Signed (twos complement) 8-bit offset byte. Used by SJMP and all conditional jumps. Range is -128 to +127 bytes relative to first byte of the following instruction. Bit:----- Direct Addressed bit in Internal Data RAM or Special Function Register. 15. Examples of instructions. MOV A,Rn Move register to Accumulator. Eg:---MOV A, r2---- the contents of r2 will move to Accumulator. MOV A,direct ---- Move contents of RAM to A. Eg:- MOV A, 6A ---the contents of RAM location 6A will move to A MOV A, @Ri ---Contents of RAM indicated by Ri will move to A. Eg:-- MOV A, @r1--- If r1=3B, the contents of RAM location 3B will move to A. 16. Examples of instructions. MOV A, #direct---- move the data immediate to A. eg:-- MOV A, #2B-- the content of A will be 2B. INC --- increment. DEC---- Decrement. MUL---- Multiply. ANL -----Logical AND. ORL --- Logical OR 17. Doubts????????