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Posted

well, I have read a lot of threads about PWM and stepper motors and so on, but I couldnt find an final answer that helps me to answer my next question.

I like to control some RC servos with the MB64. That means the DOUT have to output an PWM signal.

I'ts not really highspeed clocked ... every 20ms a pulse of 1ms (min. value) to 2 ms (max.value).

I have read that PWM needs very much performance, but I dont know if this relative slow PWM is also too much for an PIC (in the case that there are 4 to 16 such PWM needet). And finaly I have no idea how I could programm such a PWM "option"  ::).

someone tried this ?

any hints ?

Thanks

e-toy

Posted

Ahhh PWM... It's like the $64000 question around here lately!

There's a PWM peripheral on the PIC, has anyone aside from TK used it and feels like explaining it to us all? I've got a rough idea, so I'll step up and learn the rest if needed... But I don't want to reinvent the wheel if someone already knows ;)

Anyhow, that's just the one output, not 4-16, so I don't know if this is the right way to go for you e-toy.

  • 2 weeks later...
  • 1 month later...
Posted
I have read that PWM needs very much performance, but I dont know if this relative slow PWM is also too much for an PIC (in the case that there are 4 to 16 such PWM needet). And finaly I have no idea how I could programm such a PWM "option" 

someone tried this ?

any hints ?

Check this :

http://www.hobbyengineering.com/H1591.html

http://www.crownhill.co.uk/product.php?prod=1267

(looks very interesting, i ordered one!)

I plan to try it, but maybe only after my mbhp stepper motor driver :)

Posted
I like to control some RC servos with the MB64.

Hmm, i wonder : what do you plan to do with servos ?

(i just received my i2c servo driver... stay tuned ;)

Posted

I have this document : http://www.roboter-teile.de/datasheets/sd20.pdf

can someone translate this to me :

Das ist der Einschaltzustand. Der Stellbereich geht von 1ms bis 2ms bei 1,5ms Mittelstellung

(entspricht der RC-Modellbau Spezifikation). Um in den Standard Modus zurückzukommen

(falls zuvor in den erweiterten Modus gegangen wurde), muss eine 0 (Null) in das Reg 21

geschrieben werden. Werte von 1 - 255 (0x01 - 0xff) im Reg 21 schalten in den Erweiterten

Modus.

I dont understand a german word, and google translator didn't help me much :(

Should i write something to register 21 before i can use standard mode ?  :-\

Posted

Hi Bill,

it sais:

This is the state when switched "on". Selectable values range from 1ms to 2ms (1.5ms middle) like the RC-model specification). When the extended Mode has been selected, you can switch back to standard mode by writing a 0 (zero) to register 21. Values from 1 - 255 (0x01 - 0xff) in register 21 switch to extended mode

Hope this helps ;)

Best,

Michael

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