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Date: Fri, 24 Mar 2000 08:47:47 -0600 (CST)
From: Scott Dattalo <scott@dattalo.com>
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To: Cor Grooff <cogr@PDS-SITE.COM>
Subject: <private>Re: The Answer !!! :-) - 8 channels PWM generator chip.
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On Fri, 24 Mar 2000, Cor Grooff wrote:

> On Fri, 24 Mar 2000 13:47:40 +1200, you wrote:
>
> >From: Edson Brusque <brusque@FLYNET.COM.BR>
> >>    I'm making some research for a future product and want to know if
> >>there's a chip that can generate 8 PWM outputs at high frequency (say,
> >>30KHz) based on a serial input. It have to work as some kind of 8-channel
> >>DAC, but outputting PWM and not linear voltage.
> >
>
> How about a CPLD ?
>
> Macrocell counts for 8 PWM's are:
>  6 bit resolution : 62
>  7 bit resolution : 71
>  8 bit resolution : 80
>  9 bit resolution : 89
> 10 bit resolution : 98
>
>
> 64-cell CPLD's can be had for as little as $2 (altera)
>
> C

But is it possible to run the pwm counters at full speed with so few
macrocells? My experience with altera is that a 6-bit counter is about the
widest possible (for a clock of around 40Mhz). Cascading counters is relatively
expensive (but not prohibitively so - 16bit counters at the full clock rate are
possible. They just eat up more resources.)

Scott