uC with independently assignable PWM channels?

You don't say how many bits in the period register you want, how many pins you want the micro limited to, or since this is a partially designed system whether or not compiler tools have already been bought and what they may be able to compile towards. But have you already looked at PIC parts such as the PIC18F8720?

Jon

The NXP LPC2101 / LPC2102 / LPC2103 has four independent timers that each can control three PWM outputs, subject to pin multiplexing restrictions.

Karl Olsen

What frequency/time range do you need to cover ? Steppers tend to be slow devices, and you can manage a time-queue in SW, where you treat each edge as an event, and time between events, and queue which pin changes. There is a granularity limit with this approach, but it can drive to low frequencies. Many HW PWM's have a lower limit, so you'd need to flip to SW below that anyway...

-jg

With the right Cypress PSoC (Programable System on a Chip) you can

1. Select as many PWM's as there is resources available

1. Assign in PIN to be a PWM output (execept Vcc and Ground etc)

2. These are multi configurable micro's with multi configurable digial and analog blocks.

1. Does take a while to get your head around the configurabable nature

2. Free software tools

See here

Regards Joe

Which PIC was used ??

The PIC18F4431 has four stepper motor PWM channels.

don

Sure not. Good advices are dozen per dime.

There are the numerous microcontrollers with 3+ independent PWM channels. Just about any family got that. However if you inherited a half done design, the simplest way could be simulating PWMs by bit banging.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Many of the M16C and M32C have such a configuration. The M16C/29, for example, has five 16-bit PWM timers.