I got this response from SFE:
We are very sorry to hear you are having problems with your recent
I checked out the Xlinkers forum posts. It looks like a major hardware
bug was overlooked: the Tx of the JTAG and the USB are sharing a
connection. This could be creating some of the problems you are having.
All this should mean though is that you cannot use the USB and the JTAG
at the same time.
It almost sounds like the power on reset IC is on backwards on your
board. This is the first generation of these boards so it is possible
that our test procedure does not account for this particular error.
There could also be a decoupling problem that we overlooked. Try
powering the board with 9v instead of 5v and see if that fixes any of
the problems you are having.
I noticed in the forum posts that the code you are running does not
leave time in between writing to the ports to allow for blinking of the
leds. Try eliminating the redLed <: 0 statement and seeing if the red
LED simply turns on and stays on.
Make sure you are using the XC-5.xn file not the XK1.xn file. The XK1
uses the 128lqfp package where ad the XC-5 uses the 64lqfp package. Also
make sure you are using the latest release of the XMOS design tools
(v9.9), the XTAG2 and the SPI flash require the latest release of the
If errors persist or the UART bug is a problem for you we would be happy
to have your board returned. If this is the case please email firstname.lastname@example.org
. Please include a description of your problem or
this email in your message to returns.