On 02/15/2021 10:22 AM, Matthew Herd wrote:
Great, I may not be able to get back to the machine to test until the weekend,
but will update you as soon as I am able to test. But given the results I’ve
seen with the sample config, I doubt it’ll work.
Well, then something is broken. If it doesn't work, I'd
disconnect the older board and try with just one. The two
boards need to communicate over the short ribbon cable to
share the E-stop
state. Also, the watchdog timer should probably be turned
off on the 2nd board.
There was also an issue with the pull-up on the E-STOP line,
I think I may have changed the pull-up resistors some time
back to give a bit more pull-up, and added a delay. The
very old boards only gave a few hundred ns for the resistor
to pull the E-stop/ line up. If there was too much
capacitive load on the cable, it would not rise enough and
then the board would go back to E-stop.
I put a stretch circuit in the firmware to give the
resistors several us to pull the line up.
I THINK both of your boards SHOULD have this feature, but
I'm not totally sure.
One trick is to intercept and break pin 13 between the USC
board and the DB25 cable to the computer, but we ought to
determine if that is actually the problem, first.
Jon
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