Multiple PWM

N

noise0

Member
I need 3 indipendents pwm signals from a picaxe
The big one i have in my bitbox is a 28x1
Is it able to provide 3 indipendent pwm out (with different dutycycle) ??

i have read hpwm documentation... but it is not clear for me :(

can you post a brief axample code about how to get 3 pwm out from a 28x1

thanx
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hippy

hippy

Ex-Staff (retired)
Three simultaneous and independant PWMOUT/HPWM outputs is not possible from any PICAXE.

Depending on PWM frequency you may be able to bit-bang three or more channels of PWM in a form which is usable. This is one of the approaches taken to control RGB LED's.
 
premelec

premelec

Senior Member
and if you need a bunch of set and forget PWMs look at al-williams.com PAK V unit :) or use 3 PICAXE 08M cheaper...
 
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J

Janne

Senior Member
One possibility would be to use a dedicated ic for the purpose, for example A6281 from allegro. It has 3 programmable pwm channels, i think it's designed for driving rgb leds originally.
 
B

BCJKiwi

Senior Member
You can get two independent PWMs from a 28X1
pwmout on 1,
and,
an hpwm single.

For the third;
divide one of the others (if the requirements allow),
bit bang just the one ,
or as suggested, use an 08M
 
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M

Mycroft2152

Senior Member
Janne said:
One possibility would be to use a dedicated ic for the purpose, for example A6281 from allegro. It has 3 programmable pwm channels, i think it's designed for driving rgb leds originally.
Click to expand...
The A6281 will work, as long as you can handle a 16 lead QFN package - 3 mm square!
 
J

Janne

Senior Member
Mycroft2152 said:
The A6281 will work, as long as you can handle a 16 lead QFN package - 3 mm square!
Click to expand...
Hey, everything is easy if you don't have to be the one doing it ;)

Mayby there are DIP adapters available, or other chips with similar functions?
 
N

noise0

Member
thankyou for the answers
i can not go for bit-bang because i can not accept extra code complexity...
so i will go with 2 pwm as stated by BCJKiwi...
2 is better than 1 :)


p.s.
can i obtain 2 pwn on 18X too?
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hippy

hippy

Ex-Staff (retired)
Perhaps if you explain what you are trying to achieve, what your project is, people may be able to suggest ways to do that which does not make the code too complex.
 
N

nickelflipper

Member
TI (SPI), NXP (I2C) have SPI and I2C led drivers with individual PWM settings. Stock and availability is hit and miss. TI has dip pkg available, while the NXP have smt TSSOP. At the minimum, lots more friendly than QFN.
 
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