Like so many others in this thread, I’m having trouble to make my wiggler clone work properly. Mine is an olimex arm-jtag cable with (pins 8-15 connected). I tried it with ocdcommand, ocdremote and with ArmDBG. I even tried to write my own code to read back the JTAG idcode, with no luck.
Can olimex publish the schematic of this cable?
This way people can have a look at it and perhaps suggest improvements.
The problem with my clone was that the TCK signal comming from the PC was actually quite noisy. As the buffer on the Olimex clone is running at the 3.3V from the target system it will recognize all spikes etc. above 1.6V as a 1 which will generate a false clock signal at the JTAG interface. The other lines on the parallel port cable sometimes trigger the clock signal when they change their states and lead to a false clock signal.
I simply put in a 1 kOhm resistor in the DB25.5 → Jtag.9 (TCK) line in the olimex device directly in front of the buffer (need to cut the lead comming from the DB25 connector first of course) and that solved my problems.
Axel
bertrik:
Like so many others in this thread, I’m having trouble to make my wiggler clone work properly. Mine is an olimex arm-jtag cable with (pins 8-15 connected). I tried it with ocdcommand, ocdremote and with ArmDBG. I even tried to write my own code to read back the JTAG idcode, with no luck.Can olimex publish the schematic of this cable?
This way people can have a look at it and perhaps suggest improvements.
My Wiggler clone design is in the Files area of the LPC2000 Yahoo group (jtag.zip). It includes the schematic, which is probably similar to the Olimex circuit.
Leon
Sorry, perhaps I should have mentioned here that this question was already answered in [http://www.sparkfun.com/cgi-bin/phpbb/v ... php?t=2068](http://www.sparkfun.com/cgi-bin/phpbb/viewtopic.php?t=2068)leon_heller:
My Wiggler clone design is in the Files area of the LPC2000 Yahoo group (jtag.zip). It includes the schematic, which is probably similar to the Olimex circuit.