Would it be terribly difficult to make my own JTAG interface for ARM with an FTDI-chip USB module and a PIC microcontroller?
As far as using FTDI chip stuff with a PIC, I pretty much have that covered, so I’m really asking about the JTAG side of things, which is something I have never done.
The reason I’m thinking of this is because the sparkfun shop is out of stock of the parallel JTAG cable… so it seems my options are to set something up myself, scrounge around the lab and see if we have the right kind of JTAG cable kicking around somewhere (I know of one but it’s only like a 6-pin interface… I’ve been told we have others but I don’t know what they are), or order one from the one other distributor that seems to have these…
It would be much easier just to make your own parallel port JTAG interface. I have put details of one that works in the Yahoo LPC2000 group files section.
Leon
It really depends on the software you want to use:
If you want to use the openwince jtag tools, macraigor’s ocdremote/ocdcommander software, or one of the commercial ide’s, you have to build a parallel port device like Leon suggested.
If you develop a solution of your own with a FTDI chip and a PIC you have to implement the debugging software yourself (or extend an existing free software project like the OpenOCD).
If you want to use the OpenOCD anyway, you could just use a FT2232, either on a PCB you build yourself, like this: http://www.joernonline.de/dw/doku.php?i … 1_oocdlink
or using a prebuilt FT2232 module: http://www.ftdichip.com/Products/Evalua … odules.htm
The FT2232 is able to generate the JTAG protocol using it’s MPSSE, all you need is a JTAG header and a voltage regulator (you could use Vtref for that purpose, too).
Regards,
Dominic
Thanks, guys!
The FT2232 evaluation board costs a bit more than the parallel JTAG cable does in the first place, and building a PCB for one would probably cost even more in terms of time and effort.
I guess that means I’ll be going with parallel. 8)