Let's Make Robots!

PWMOUT only on two output, that are really inputs?

Am I reading the manual (section 2, page 128) correctly? Can I only use the PWMOUT on 2 specific ports on my 28X1?

This would mean that I can't run more than two outputs with pwm, and that has to be the digital in/outs 1 and 2, so there's no hope of running it through the onboard L293D??

I must have missed something, surely there is a way around this. Pulsout maybe? I'm R'ing T. F'ing M. now, but if somebody already knows the answer, that would be helpful..

 

 


EDIT:

 

Oh, wait, HPWM (page 62) might be what I'm looking for, isn't it...?

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There is simply no way of running PWM and servos at the same time. I switched to an I2C servo driver for this reason -By the way there is a good servo driver chip available for about 20 bucks... And yes, this is a major downfall of the 28x board.

Now, in terms of the Hpwm stuff... No one anywhere knows how it works -it you get it done, you would be the first.

Time to make your own board

i don't see what's so hard about hpwm... the manual says it all!

I swear...

Now I like to think I am a fairly competent guy... I screwed around with the HPWM stuff for somewhere around a week and still could not figure it out. I read and reread the manual and still nothin'. Since then, I have heard nothing but the same from others.

I would LOVE to see one of us get it but man, I think it is just the picaxe programmer/ developer guys just fucking with us. I really don't think it exists --Like Sasquash or a straight man who can pick curtians that match both the couch and carpet.

maybe Sasquash IS HPWM! :) i'll give it a go when i have some free time, maybe having an oscilloscope might help in this case (but i don't have it!)

But, if I only use the PWMOUT upon startup, and then only use PWMDUTY after that, would that allow for use of servos?

If I understood the manual correctly PWMDUTY wont  reset the internal clock...

As far as i know you can't. If you have your PWM already running that means it is using the internal timer to coordinate itself. Whenever you call the servo command (since it sends pulses at regular timings, similar to PWM in some way) it screws the timing for PWM, and vice-versa (if you call pwm after servo, the servo timing gets screwed).

I guess you'll have to use 2 brains... 

so if I hook oddbots Simple motor control to a PWM output, I'll Have smooth motor operation, But I can forget about running any servos? fuggit! I left my manuals at work and hate reading on screen. This'll be a loong weekend...

You can have smooth motor operation with oddbots simple motor control, but you'll have to program the PWM bit yourself. You can use both commands in one program, but they wont run at the same time because they both use the same timed interrupt to run in the background.

Its not all that hard to write your own PWM code to pulse the motor controller pins.  

My circuit does not have to be driven by PWM. You can just turn the motors on or off. And servos can be used, just not while PWM is being used.

What kinda quiter talk is that?

Yes on a picaxe 28X1 inputs 1 and 2 become PWM 1 and PWM 2. Apparently the starter kit has some limitations but that doesn't mean you can't circumvent them. Use you imagination, there is always a way.

Appendix E of Manual 1 is quite useful when optimising your ins and outs.

 I know that the schematic for the board has been posted on this site but apparently not tagged as I could not find it.