1. Micro-processor vs. Micro-controller

2. PIC16F877 40pin DIP CMOS technology RISC CPU
35 single word instructions
DC-20MHz clock
DC-200ns instruction cycle

3. PIC 16F877

4. Clock/Pipeline

5. Program Memory/Stack

10. Instruction Set Default destination STATUS Register
Subtraction (Borrow Flag)
W EQU H'0000' ; standard definitions
F EQU H'0001'; ...to avoid having to write numbers
incf var,W ; W = var + 1, var is unchanged
incf var,F ; var = var + 1, W is unchanged
addlw sublw 2

11. Bit, Byte, Literal/Control Instruction Formats

13. Tool Chain (MPLAB/CCS)
Programming facilities
Pre-processor functions
Code checking/warning
Prepared include/library files
Debug without hardware
limited programming cycles
safety -- bugs may blow equipment
Debug with equipment
on-line view of register values help to track down problems.

14. Lab Exercise: Failing loop test
#device PIC16F877 *=8 ADC=8
void main() {
int c;
for (c=9;c<=255;c++); }
movlw 0x0
A movwf 0xA
goto MAIN
nop
MAIN clrf 0x4
F movlw 0x1F
andwf 0x3
movlw 0x9
A movwf 0x21
AA incf 0x21
000A goto 0x9
000B sleep

15. Working loop test (1) #device PIC16F877 *=8 ADC=8 void main() { int c;
for (c=9;c<=254;c++); }
movlw 0x0
A movwf 0xA
goto MAIN
nop
MAIN clrf 0x4
F movlw 0x1F
andwf 0x3
movlw 0x9
A movwf 0x21
FF movlw 0xFF
000A subwf 0x21,W
000B btfsc 0x3,0x0
000C 280F goto 0xF
000D 0AA incf 0x21
000E goto 0x9
000F sleep

16. Working loop test (2) #device PIC16F877 *=8 ADC=8 void main() {
long c;
for (c=9;c<=255;c++); }
movlw 0x0
A movwf 0xA
goto MAIN
nop
MAIN clrf 0x4
F movlw 0x1F
andwf 0x3
A clrf 0x22
movlw 0x9
A movwf 0x21
000A 08A movf 0x22
000B 1D btfss 0x3,0x2
000C goto 0x11
000D 0AA incf 0x21
000E btfsc 0x3,0x2
000F 0AA incf 0x22
A goto 0xA
sleep

17. Another loop Fails #device PIC16F877 *=8 ADC=8 void main() { int c;
do{}while (c++ <= 255); }
movlw 0x0
A movwf 0xA
goto MAIN
nop
MAIN clrf 0x4
F movlw 0x1F
andwf 0x3
movlw 0x9
A movwf 0x21
goto 0x9
000A sleep

18. While Loop OK! #device PIC16F877 *=8 ADC=8 void main() { int c; c=9;
do { } while (c++!=255); }
movlw 0x0
A movwf 0xA
goto MAIN
nop
MAIN clrf 0x4
F movlw 0x1F
andwf 0x3
movlw 0x9
A movwf 0x21
movf 0x21,W
000A 0AA incf 0x21
000B 00F movwf 0x77
000C 0A incf 0x77,W
000D 1D btfss 0x3,0x2
000E goto 0x9
000F sleep