16 bit PWM using CCP1

[Bruce]

Hi Darrel,

Pretty cool stuff. Have you tested this on other 18F parts? I don't have a 4520 to test
with, but I couldn't get this to work without clearing CCP1CON before moving 9 to it on
a 452 or 4431.

Had to do this;

ASM
MyInt                    
    clrf CCP1CON         ; 18F452 & 18F4431 require this before it changes CCP1 output
    movlw 9
    movwf CCP1CON
    bcf PIR1,TMR1IF      ; clear TMR1 int flag
    retfie FAST          ; use RETFIE FAST to restore WREG, STATUS & BSR
ENDASM

On an 18F452 or 18F4431, the above works fine, but only if I clear CCP1CON first.

This works on a 452 & 4431 with CCP1 & TMR1 ints enabled on any output pin;

ASM
MyInt                    
    btfss PIR1,TMR1IF    ; TMR1 interrupt?
    bra CCP              ; no - service CCP interrupt
    bcf PIR1,TMR1IF      ; yes - clear TMR1 int flag
    bsf LATB,0           ; set RB0 on TMR1 interrupt
    retfie FAST          ; return
CCP
    bcf PIR1,CCP1IF      ; clear CCP1 int flag
    bcf LATB,0           ; clear RB0 on compare interrupt
    retfie FAST          ; use RETFIE FAST to restore WREG, STATUS & BSR
ENDASM

I was just wondering if this might be a fluke with the 4520 part - since none of the other
18F parts I've tested will toggle CCP1 with just the movlw 9, movwf CCP1CON?