make JTAG debugger using Wiggler & USB-to-parallel

Development Boards MicroMod
1

First let me make it clear that the particular USB-to-parallel port adapter I am talking about is NOT the typical printer adapter, it is a design based of Objective Development’s V-USB. Please have a look: http://www-user.tu-chemnitz.de/~heha/ba … -16.htm.en

What I plan on doing is: instead of wiring the pins of the ATmega to a DB connector, I will wire them to a JTAG connector directly instead using the Wiggler parallel port JTAG debugger design, similar to http://www.frozeneskimo.com/electronics … ler-clone/ but there are many MANY similar examples out there.

My major concern at this point is the speed at which the parallel port can operate, and the speed that JTAG requires. Apparently the USB2LPT 1.6 design can get about 1kb/s of input/output speed. Is there a minimum speed that JTAG, and various debugging software requires?

Olimex’s products seems too expensive, and I already have plenty of components around to build this.

2

I can’t see that working, the software needs to drive the pins directly.

Just buy a Dragon. It’s much better value than the Olimex units.

3

I have an AVR Dragon, is that what you are talking about? I don’t see the AT91SAM7X series under supported devices.

4

I thought you wanted something for debugging the ATmega, which is why I suggested the Dragon. There are several low-cost USB JTAG ARM interfaces, I use the Rowley CrossConnect Pro but I’ve also got one of the Amontec JTAG-Key Tiny units.

As I said, I don’t think your idea will work.