AVR-USB-JTAG connections to stk500

Development Boards MicroMod
1

Hello;

I just got my nice new avr-usb-jtag, and I want to make sure I have some things right before I blow it up.

I want to hook the usb jtag to my stk500 for debugging. I’ve been looking through atmel and the olimex docs and I think I have it right, but thought I had better check.

My intention is to make a little connector board that plugs into the expansion connector on the stk500 (like the atmel jtag’s do). I think the proper connections are:

jtag 1 (TCK) -> exp 28 (PC2)
jtag 2 (GND) -> exp 19 (GND)
jtag 3 (TDO) -> exp 26 (PC4)
jtag 4 (VREF) -> exp 22 (VTG)
jtag 5 (TMS) -> exp 27 (PC3)
jtag 6 (NSRST) -> exp 15 (RST)
jtag 7 (VCC) ->  ?
jtag 8 (NTRST) -> no connection
jtag 9 (TDI) -> exp 25 (PC5)
jtag 10 (GND) -> exp 19 (GND)

Do I need to hook the usb jtag 7 (vcc) to the target? If I read the atmel sheets right the atmel ones don’t, but I don’t know if the olimex ones need that. I don’t need to add any pullup resistors or anything other than just pin connections, do I?

And in a related question. The STK501 adapter for the 500 (which lets you use the mega128 chips on the stk500) has a jtag connector, but can you use it to debug (jtag compatible) chips on the stk500, or only the chips directly on the 501? (The help file says “The JTAG connector is intended for the ATmega64, ATmega128 and ATCAN1m128 that has a build in JTAG interface”).

Thanks,

Steve

2

Hey, a followup to my own post.

I have successfully made the olimex unit work with my stk500. I did, in fact, have to provide power to jtag 7 (vcc) to make it work. I tested all this first by jamming little wires in the holes of the two connectors, and when that worked out I made a little circuit board header adapter.

So the proper connections were:

jtag 1 (TCK) -> exp 28 (PC2)
jtag 2 (GND) -> exp 19 (GND)
jtag 3 (TDO) -> exp 26 (PC4)
jtag 4 (VREF) -> exp 22 (VTG)
jtag 5 (TMS) -> exp 27 (PC3)
jtag 6 (NSRST) -> exp 15 (RST)
jtag 7 (VCC) ->  exp 22 (VTG) (same as jtag 4)
jtag 8 (NTRST) -> no connection
jtag 9 (TDI) -> exp 25 (PC5)
jtag 10 (GND) -> exp 19 (GND)

And, I had a nice reply from the folks at Atmel who confirmed what the schematic for the stk501 (mega128) adapter implies, that you can use the stk501 jtag connector to debug the chips on the stk501, but the support doesn’t extend down into chips mounted in the stk500 itself.

I will also add that using AVR studio 4.12 build 460, that the AVR-USB-JTAG is detected and works without problems (at least what I’ve tried so far). Single-stepping, programming, verifying, etc.

Best regards,

Steve