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SECTION V-7: Using EQU for Special Function Register Address Assignment
EQU is widely used to assign special function register (SRF) addresses. Examine the following code.
| COUNTER EQU 0x00 | ;counter value 00 |
|---|---|
| PORT EQU 0xFF6 | ;Special function register Port B address |
| MOVLW COUNTER | ;WREG = 00H |
| MOVWF PORTB | ;Port B now has 00 too |
| INCF PORTB, F | ;Port B has 01 |
| INCF PORTB, F | ;increment Port B, Port B = 02 |
| INCF PORTB, F | ;increment Poer B, Port B = 03 |
The above is for the PIC18 family. If you use a different PIC controller such as PIC16F, where Port B is a different address, then change the EQU address for Port B and reassemble the program and run it.
| COUNTER EQU 0x00 | ;counter value 00 |
|---|---|
| PORT EQU 0x07 | ;Port B address in PIC16F |
| MOVLW COUNTER | ;WREG = 00H |
| MOVWF PORTB | ;Port B now has 00 too |
| INCF PORTB, F | ;Port B has 01 |
| INCF PORTB, F | ;increment Port B, Port B = 02 |
| INCF PORTB, F | ;increment Poer B, Port B = 03 and so on... |