2 PWM in 16F690 problems

[Peaps]

Hi.

Did you get anywhere with the PWM code for the 18F1330?

I don't think that you can use HPWM with this device as it's PWM module is completely different to the normal PWM module found in 16F chips. It requires many registers to be set manually.

Am currently working on this, but experiencing problems...

Andy

[ciendavila]

You have to acces direct to the registers, and configure the internal OSC to work with it..
The pwm duty cycle works with 14 bits, so you have to write directly the value on the PDC0L register for the less significant bits and the PDC0H for the more significant bits of the PWM 0 channel..

I hope these can help you, if you download the datasheet you will understand more the code that I wrote.. These is part of the code of my program:

OSCCON.6 = 1 'configure the internal oscilator to work at 4 MHz
OSCCON.5 = 1
OSCCON.4 = 0
OSCCON.1 = 1

PTCON0 = $00 ' configure frequency and the PWM sets
PTCON1 = $C0
PWMCON0 = $37
PWMCON1 = 0
PTPERL = $AA
PTPERH = $01

PDC0L = $FF ' Set the duty cycle for PWM 0
PDC0H = $00
PDC1L = $FF ' Set the duty cycle for PWM 1
PDC1H = $01

[Peaps]

Hi, thanks for the reply.. I got it working in the end.

The thing that I was doing wrong was having a larger duty cycle value in PDC0L and PDC0H than the value in PTPERL and PTPERH. Since the PWM module counts upwards until it reaches the duty cycle value, and then continues to count upwards to the end of the frequency cycle as determined by the values in PTPERx registers, PDCxx must be lower than PTPERx.

Thanks again,

Andy