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Re: Freed Z80 USB port - Success!



David Wilson wrote:
On Mar 16, 8:50 am, Steven Hirsch <snhir...@gmail.com> wrote:
Getting USB working was quite a battle, complicated by the fact that the base
circuit board did not connect everything that was needed.  I assume because
this functionality was in a prototype phase.

What was missing?

All the power connections to the USB module and a pull-down resistor that holds ROM A15 low. I built mine from a kit and never picked up on what the blank SMD pads were for. The lack of that pull-down was also making resets flakey, so this killed two birds with one stone.

Alex posted GAL equations that had his card talking to the USB module
- did you use those or develop your own?

No, I used his.  The GAL wasn't the issue.

As soon as I find my USB module at home I am going to try it out on my
card.

Send me private e-mail if you want a copy of ZMP pre-configured for the adapter.