harshit suri wrote :
>
> I need a chip that gives me 4 channels of PWM . I want
> 4 simultaneously
> operating PWM channels. Preferable frequency of
> generation should be greater
> than 50 Khz.
>
> I wish to have at least 8 bits of resolution PER
> channel. meaning 256 levels
> of speed control (The application is DC motor speed
> control)

What kind of motor ? Large ? Small ?
If your *other* costs in this project (such as
motor power drivers and power supplies) you might
use some small PIC and use one per motor. Such as
the 16F628 or 627. Buy using the builtin USART
and PWM hardware, you would get a quite easy
programming task. Using a single PIC and software
PWM would probably also work, but with more programming
and testing work. The one-PIC-per-motor solution is
also much easier to adopt to more or fewer motors
then four.


> I wasn't being able to find a cheap solution. so i
> thought id buy a cheap
> PIC. Program it so that my main microcontroller can
> send commands to the PIC to adjust the speed levels.

How will the "commands" be sent ?

> I was looking at the microship site and prefered the
> flash devices as they are reprogrammable.
> I found the PIC18F448 Family : it had 5 PWMs
> advertised.

Note that most of the PICs with multiple PWM outputs
can not be used as *separate* PWM channels. They are
ment to be used in a bridge design where the different
outputs are driven in from a common time base. I'm not
sure about the 18F448, though...

> But it seemed an overkill as it was a 40 pin device.
>(I prefer DIPs).

There are 40 pin DIPs.

>
> I have never worked with PICs before. But do know they
> are cheap and simple devices to work with

>
> 1)Pls suggest a chip : any chip which can do the
> above. and has minimal I/o
> and is cheap :-)

See above.

> 2)Can anyone give code for the same.

Give ???

Jan-Erik.

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