No breakout board could be considered universal if it doesn't also support JTAG. I've now made a proof of concept implementation that demonstrates this on the example of the Milkymist One.
All the protocol handling is done by UrJTAG. For simplicity, I use the "gpio" cable driver, which accesses GPIOs through /sys/class/gpio/... and is therefore not exactly a speed demon. This is what the whole setup looks like: http://downloads.qi-hardware.com/people/werner/ubb/jtag/ubb-jtag-m1-all.jpg Since the JTAG interface of Milkymist One runs at 2.5 V while the Ben uses 3.3 V, the adapter has a few voltage dividers acting as level shifters: http://downloads.qi-hardware.com/people/werner/ubb/jtag/ubb-jtag-m1-card.jpg Since I don't have a mating connector for J6 (2 mm pitch) at home, I improvised by making individual cables with receptables for 2.54 mm headers: http://downloads.qi-hardware.com/people/werner/ubb/jtag/ubb-jtag-m1-j6.jpg A README with all the gory details (there a few quirks), a schematic drawing, and cut-out labels for the wires can be found here: http://projects.qi-hardware.com/index.php/p/ben-blinkenlights/source/tree/master/ubb-jtag - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
