12f683 variable HPWM and fixed pulse tick thickness

[Acetronics2]

Hi,

With the internal osc , even @ 8Mhz, HPWM definitly is not what to use ... so is pure basic ...

with 10ms steps ... you'd better use PAUSEUS to generate the pulse ( need 16 Mhz ext osc ! ... or 8 asm NOP's @ 8Mhz ), and a timer to generate an interrupt every 10 ms that will change the pause beetween pulses ...

see Darrel's Instant Interrupts for easy interrupts ...

May be also a very very smart solution with the COMPARE mode of the CCP that can change the CCP outpin and set the CCPIF just when pause ends ...

Alain

[mark_s]

One of many possible approaches. Here the way I have done this.

First I generated my adjustable frequency using HPWM set to approximately 50% duty. Next I fed the output from CCP1 pin
to Portb.0 pin. Using DT interupts "INT_INT" set to trigger on the rising edge of my pwm signal. In the ISR the output pin was toggled

Basic concept

Setup HPWM
Set INTCON to trigger on rising edge
Main:
 Read Buttons or ADC
 Set HPWM Frequency
 Goto main


Interupt Service Routine:
gpio.x = 1
pauseus 5
gpio.x = 0
INT_RETURN

Not sure if you have enough pins using a 12f683 to do this and what ever else you need?

[RCtech]

Thanx a little bit late for your both replies.
Not as easy as I expected, I'll have to learn more and will start seeing Darrel's Instant Interrupts.

... and will be back again if I need help with these interrupts.

Thank you.