Picaxe 20x2 no Hardware PWM mode 1 on early models?

[Adiman]

Hi guys,

I have recently had to delve into my stash of older Picaxe chips as I had burned out my newer ones (don't ask) - These are probably circa 2010

I have found that HPWM Mode 1 is not working correctly on these two older chips. The 'high' side output is working on Pin c.5 but there is no output on the 'low' side pin c.4

For example:

setfreq m64
HPWM 1, pwmHHHH,1,249,800

should give me an output on the high (c.5) and low pin (c.4) at 64khz, opposite to one another, at approx 80% duty cycle.
Only the high side is working. No sign of life on the low side, when measured with an oscilloscope or multimeter.

If I do a HIGH c.4, the output works, so the pin appears to be okay.

This was working fine with the newer Picaxe 20x2's I had. So i'm wondering if there was a problem with earlier Picaxe 20x2's or they changed the way HPWM functions.. or am I just unlucky and have two faulty Picaxe chips?

Cheers,

Adrian

 

[pxgator]

Hi Adrian,

If you look at the revision history tab at the link below it seems there were some pwm problems in
the past. However they do list some workarounds for these problems.

http://www.picaxe.com/Hardware/PICAXE-Chips/PICAXE-20X2-microcontroller/

 

[Adiman]

That was exactly it! Thanks for pointing me to the revision history..

and the workaround does work, it's not pretty though

New 20x2 chips on order!

Adrian