A newbie question

About 5 month ago, I purchased an AVR-JTAG-L. I am trying to use it for the first time. But i got a big problem. I can’t make it work at all.

I am doing this:

I connect it to my board and to my PC.

I turn the power on my target board and the JTAG ICE LED turns on.

Then I run AVR Studio 4.09.

I select platform JTAG ICE → ATmega64.

I got a response “Could not connect to JTAG ICE on port Auto”.

The AVR JTAG-L led stays firmly turned on.

The AVR-JTAG-L is connected to my COM1.

I am using an ATmega64L in my target board, running at 8 MHz.

My ATmega is ‘virgin’, it has never been programmed.

The JTag ports (F4-F7) are connected only to AVR JTAG ICE.

The AVR JTAG-L VREF pin is connected to its VCC.

The PEN pin on the uC is connected to VCC

The RESET pin on the uC is connected to VCC through a 4K7 resistor

I am using external RAM

Please, what might be going wrong?

do you use clean COM port or it’s USB to RS232 converter?

do you have other devices connected which may interferent com port use?

Best regards

Tsvetan

I am using a clean COM1

No, I don’t have anything that may be interfering with COM1. I can open it using TeraTerm or HyperTerminal and I can use it normally with Atmel AVR ICE500.

I have 2 AVR-JTAG-L and 2 serial cables. I tried to replace then and the result is the same, wich means the problem is not in the cable neither in one of the AVR-JTGA-L

There’s some things that I forgot to mention.

  1. My uC and the AVR-JTAG-L are both powered with 3.3 V.

  2. The board is a new prototype and it has never been tested. It’s not my first project with Atmega, but the first using the JTAG interface.

Since the board has never been tested, I am not sure if it is working, so I have a few questions:

What should happen if the uC is without clock, or it is damaged? Should the AVR-JTAG-L behave this way or should it at least give a sign of life?

I also tried to power only the AVR-JTAG-L in a protoboard with 5V. I connected only the VCC, VREF and GND pins. Then I launched AVR Studio and I got the same message: “could not connect …” Is this behavior normal?

I’ve never upgraded the firmware. The AVR-JTAG-L has been purchased in jun 2004. Is there a new fw version since there?

These types of posts bother me a bit. Nothing against you Dirceu, but there are some simple things to consider before asking for help. Basically, you should have mentioned that you have a prototype/untested setup. Obviously, if both JTAGs and cables are not working, you have an issue with your board. Double check your connections with a continuity meter and the datasheet. You may need to start with a JTAG and a simple breadboard setup to get your feet wet if you are not comfortable troubleshooting custom hardware.

-Nathan

@ Nathan

I think there’s no need to be agressive. Posts like yours won’t help at all.

I am a newbie using AVR-JTAG. But I am not a newbie designing and testing electronic circuitry. I wouldn’t like to bother anyone with such a stupid question if I hadn’t tested all the connections before.

I’ve checked the connections 4 times. I’ve checked the connection schematics against other JTAG compatible circuits. I’ve checked the serial cable.

The question is: I’ve never used AVR-JTAG-L before. The documentation is weak. I don’t know whether the LED should stay ON, OFF or blinking. I didn’t find such information on the AVR-JTAG-L documentation. If the AVR-JTAG-L documentation were more detailed, I wouldn’t need to write this stupid question here.

It would help a lot if you (or someone else), instead of only criticize me, could answer at least one of my questions:

  1. What should happen if the uC is without clock, or it is damaged? Should the AVR-JTAG-L behave this way or should it at least give a sign of life?

  2. I also tried to power only the AVR-JTAG-L in a protoboard with 5V. I connected only the VCC, VREF and GND pins. Then I launched AVR Studio and I got the same message: “could not connect …” Is this behavior usual?

“Could not connect to JTAG ICE on port Auto” has nothing to do with the connection between JTAG and target, assuming at least power lines are ok. Check the voltage is ok (pin 4&7 VCC, and 2&10 GND), then check the connection between JTAG and PC; try another rs232 cable, try another cable again; try another COM port; try another PC.

The JTAG should be seen even there is no target; the target can be programmed without a clock installed, JTAG provides its own clock.

Sometimes checking 4 times isn’t enough; sometimes another pair of fresh eyes may be the key.

Keep trying, it must work.

Cosmin