Trying to load code to new hardware

[gerrykurz]

The second command seems to work:

[gerrykurz]

I am getting an error message from xrun:



I have to hit Try Again several times but then it seems to work.

I got xrun to find the devices with a speed setting of 4 but not 3.

What does this indicate to you? I am able to look at the board with a high speed scope tomorrow, what should I look for in your opinion?

[segher]

Excellent :-)

What you should probe is the TMS signal, both before and
after the O/D buffer (the 7407).

To fix it, use a push/pull buffer on this signal (as you have
on the clocks already; maybe there is a spare left, or you
can share the two TCKs). As a quick fix you can reduce the
pullup resistor on TMS (to 500R or so).

Say this net has a few pF of capacitance; the 10kR pullup
then gives it a rise time of a few tens ns. That does not
work with a signal switching faster than a single MHz or so :-)

[gerrykurz]

Thanks everyone, this problem has been fixed. The problem was the pullup on TMS.

Here is the TMS signal with the 10K pullup in the original design:



And here is the TMS signal with a 330 ohm pullup:



Onto the next problem......