Having just been programming up a pile of balloons using the
Xilinx-type devices I note a few points of interest.
1) The code released in test-v0.3 only supports the xilinx-type device
not the older LART dongle because I didn't get round to putting a
command-line option in. You need to rebuild it for the older device.
2) The really annoying problem that on Balloon3, leaving the JTAG
device attached disables the PCMCIA from working (fully), does not
happen with the Xilinx-type device, presumably becuase it lets the
relevant pins float. This is a good reason not to use the LART-style
any more.
3) Currently a breakout board is needed to go from the board to the
FPC. This is now documented on the Wiki. (The version in the test v0.1
Docs 'Configuring L3' has TDI/TDO swapped.)
http://balloonboard.org/balloonwiki/BalloonJTAGing
is currently definitive.
Further JTAG developments are on the way: Getting it working with USB
dongle would be nice (either the Guralp design on the Wiki or the
various FTDI-based device), and cooler than that Dave Bisset is working on a
thing that will let a balloon program a whole pile (8?) more devices
at furious speed by using the FPGA as a high-speed JTAG engine.
Wookey
--
Principal hats: Balloonz - Toby Churchill - Aleph One - Debian
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