LM 629 Motion Control Chip

Hey,

I needed some help in learning how to use the LM629 to control DC motors. Currently I am able to reset the LM629, but when I am checking the busy bit soon after reset, it is staying high indefinately. I am using motorolla's HC11 as my microcontroler which has a different clock speed as compared to the LM629. Could it be a problem with timing?

If anyone has any suggestions (or basic code that I can compare) I would greatly appreciate it.

Thank you,

Devang snipped-for-privacy@seas.upenn.edu

Reply to
Devang Shah
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I'm pretty sure you can't connect the HC11 to the LM629 without some bit banging or additional glue chips. That you're asking about their respective clock speeds suggests that you didn't take a careful look at the data and control line interface timings. But maybe you did...?

Mitch Berkson

Reply to
Mitch Berkson

Reply to
Blueeyedpop

I guess the first things I would check are

  1. Reset polarity (LM629 reset is active low)
  2. /CS, PS and /RD polarity and timing

PS state must be valid before /RD falling edge

  1. If you are using a I/O port on the host CPU for the 8 bit data bus, that you have the port in input mode before atemting to read the LM629 status register.

  1. LM629 clock running and appropriate frequency (6 or 8 MHz)

  2. I have a note in my source code for LM629 access that says newer chips ( newer than 1989 date code!) crash if the status register is polled to frequently, you might need a delay in your polling loop.

Peter Wallace

Reply to
Peter C. Wallace

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