More about HPMW command

S

Steve Joblin

Member
For my next robot, I want to use a 28X and L293D to control my two small drive wheels. I think I want to make use of the HPMW command to control speed, but the manual has left me a bit confused... it references "See the hpwm motor driver datasheet for more details.", but I can't find such a datasheet...

Am I on the right track to be able to "set and forget" a speed and direction using the HPMW command so that I can do other things like check a sensor?
 
hippy

hippy

Ex-Staff (retired)
I think there's some confusion with HPWM and the 28X/40X. The manual indicates it's available for the 28X/40X and while "HPWM OFF" compiles ( 5.1.3 ) "HPWM" otherwise gives a not supported error for those PICAXE's which is what I'd have expected - they do not have the required hardware for HPWM.

The PWM command allows control of two independent motors on the 28X/40X and 28X1/40X1 in the background so it's set and forget as you'd like, but HPWM on the 28X1/40X1 is only available for one of those two motors. It too is set and forget.

For the 28X1/40X1 you can use PWM on motors 1 and 2, or you can use PWM on motor 1 and HPWM on motor 2. That's down to PICmicro hardware, not an artificial PICAXE limitation.

For the 28X/40X you can only use PWM on motors 1 and 2.

An alternative approach would be to use a 14M to give HWPM control of the other motor with a 28X1/40X1 or to use two 14M's with other PICAXE's.
 
S

Steve Joblin

Member
Thanks for the quick response Hippy (by the way, I love the AIterm (you should put a link to it on your site!).

I guess that is where my confusion first started... what is the difference between PWM and HPWM?

Edited by - steve joblin on 04/07/2007 16:49:19
 
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