hi rurik,
does everything work OK if you don't do JTAG chaining?
cascading ibobs in a jtag chain can be problematic.
you might want to probe the data and clock lines
with a high bandwidth scope
(use low capacitance probe and a short ground clip)
to see if there is ringing on the jtag lines.
what download cable are you using?
xilinx parallel cable IV works. others may not.
best,
dan
Jason Manley wrote:
The KAT guys were complaining of a similar behaviour, but I can't say
I've ever experienced this myself and have been unable to reproduce it.
Is your problem repeatable?
Have you enabled the "Load FPGA" option in Impact?
Also check the MODE jumper settings on your IBOB. It shouldn't affect
anything if you're programming over JTAG, but might be worth a look
anyway. Should be on 3-4 if you're not using the EEPROM.
Jason
On 27 Jan 2009, at 19:29, Rurik Primiani wrote:
Hi everyone,
We've been experiencing issues with hanging serial ports when
reprogramming our iBob's over JTAG. Our setup at the moment is a linux
control computer with an 8-port serial-PCI card with two iBob's
attached and four iBob's total on a JTAG chain (the first two being
the serial-linked ones). Programming works just fine and from a cold
start so does serial communication usually.
The problem occurs when we reprogram a board with a *different*
bitstream, the serial port hangs permanently until the iBob's are
power cycled and reprogrammed. Programming the same bitstream
typically does not break the port. Occasionally however even the
power-cycling and reprogramming does not bring back the serial ports.
It does not seem to be the specific designs because they usually work
after this procedure, instead it seems to be linked to the reprogramming.
Has anyone seen this behavior before, or something similar to it? It
appears to me that during an iBob reprogramming some pin that controls
the serial port fails to go low but perhaps it's a linux multi-serial
port problem?
Thanks for your help!
Rurik
