This is mostly in context with the Mesa M5i20 board. I have a new project
where I need to control two micro-stepping stepper motors, as well as a
laser. The laser takes a PWM input. I am pretty much committed to the m5i20
for the PWM, but at the same time need to generate 60-70Khz step and
direction for the two stepper motors. The current configuration is for 16
micro-steps per step, where the stepper module accepts up to 70Khz for the
step input, although the maximum rate I would need is more like 60Khz.
What are my options? For a servo system, using a 2.54Mhz processor, I was
able to crank up BASEPERIOD to 50Khz in a system which also used the m5i20.
However if that resulted in over driving the PCI bus, I am not sure that
would be apparent in a servo system. Using ordinary outputs on the m5i20, is
it possible to generate a 50-60Khz step signal, given a sufficiently fast
Alternatively, and I have not looked into this too much, how much would be
involved in changing the FPGA configuration to support step and PWM outputs.
My thought is to just slightly modify the existing m5i20 EMC configuration
to either be able to set a bit (in the interface, i.e. RegMap) to indicate
whether to generate PWM or Step signals on the specified output, or to have
PWM and Step simultaneously available on separate outputs (on P3 or P4
connector, if something on P2 cannot be reused).