Hi Peter
Peter Chant schrieb:
> void pwm_setup(void) {
> _asm
>
> ;#define STATUS 0x03
>
make sure that bank0 is selected here (BCF STATUS, RP0)
> CLRF CCP1CON ; CCP Module is off
> CLRF TMR2 ; Clear Timer2
> ;clrf 0x11 ; timer 2 is 0x11
> _endasm;
> CCP1CON = 0;
> TMR2 = 0;
the last two c-code lines are equal to the first two assembler lines above
> _asm
>
> MOVLW 0x7F ;
> MOVWF PR2 ;
PR2 is in Bank1, you need a bsf status, RP0 before accessing PR2
> MOVLW 0x1F ;
> MOVWF CCPR1L ; Duty Cycle is 25% of PWM Period
CCPR1L is in bank0, dont forget to do bcf status rp0
> CLRF INTCON ; Disable interrupts and clear T0IF
> ;BSF STATUS, RP0 ; Bank1
> bsf STATUS,5
> ;BCF TRISC, PWM1 ; Make pin output
> bcf TRISB,3
> CLRF PIE1 ; Disable peripheral interrupts
> ;BCF STATUS, RP0 ; Bank0
> bcf STATUS,5
> CLRF PIR1 ; Clear peripheral interrupts Flags
> MOVLW 0x2C ; PWM mode, 2 LSbs of Duty cycle = 10
> MOVWF CCP1CON ;
> ;BSF T2CON, TMR2ON ; Timer2 starts to increment
> bsf T2CON,2
If the code doesn't run as expected then there is a problem in your
hardware, wirering, config etc. etc.
Things to check:
- Does your cpu runs at all? Toggle a bit on the pwm port and try to
measure the frequency.
- What else are you doing in your Programm. For testing you should have
after the initialization just a while(1) {} loop in your main().
- Important: Did you enable the watchdog in your config register? If so
disable is.
Regards,
Jan
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