Board Reset

[samOC]

I was running my IsoPod V2 off of a battery. The battery went dead and as a result the IsoPod was powered on and off quickly for about a half second. I unplugged the IsoPod from the battery and back in to the wall outlet provided. Now I cannot connect to the board through JTAG. When you power on the IsoPod, all of the LEDs come on as if the board is in reset. When I try to connect through the JTAG (using metrowerks codewarrior) it says it cannot connect to board. I have no idea how to debug this one. Faulty JTAG cable? Corrupted Flash? There was a program loaded that should be running but the board won't come out of reset and run it. I'm at a loss here.

The only thing I knew to check on the JTAG cable was the reset signal. It is normally high and when I hit debug in MetroWerks, the signal does not go and stay low like I thought it would. And, the +3.3V line on the JTAG cable is actually 5v. Does this mean the JTAG cable is bad?

[nmitech]

the +3.3V line on the JTAG cable is actually 5v. Does this mean the JTAG cable is bad?

Your JTAG cable is OK. What you see is not the actual 5V output from the Jtag rather than a floating (5V) signal that powered by the input signals of the buffer chips. Once you plug on the IsoPod, it will read 3.3V on the VDD.

When I try to connect through the JTAG (using metrowerks codewarrior) it says it cannot connect to board.

I saw your previous post and you said your Jtag problem has been solved.

http://www.newmicros.com/discussion/showthread.php?threadid=331

[samOC]

Your post is missing the link to the thread you are refering to

[nmitech]

I found your previous post and you said your Jtag problem has been solved.

http://www.newmicros.com/discussion/showthread.php?threadid=331

[samOC]

This is obviously not the same problem that was in the previous post you referenced. I solved that one and the board has been working fine. It suddenly, and without explanation, stopped working. The previously mentioned problem did not cause the IsoPod to be stuck in reset.
I checked to make sure that the problem wasn't the previous one by trying to use the JTAG loader provided on Peter Gray's website. I followed the exact steps that previously worked and the loader tells me that the board is not responding. This is a problem with the IsoPod itself if the JTAG cable is ok.

[nmitech]

the board is not responding
Here is the checking list,

Power
OS configurations for parallel port
IsoPod
Jtag Cable


Power the IsoPod without Jtag cable plug in,

Check J2 pin 1, it should read ~3.3V.

Check VDDA(Vref) on J3 pin 1, it should read ~3.3V

Check the Reset signal on J2 pin 9, it should read ~3.3V

Check the crystal, the pin next to GND signal of J1 (on bottom size) is oscillated (~2.0V).

These are the four critical elements that CPU needs to operate.

With the Jtag cable plug in, the reset signal should stay at 3.3V level even when you flash the code. The only short time the reset goes low is when the flash loader program initiates then it goes back high.

Before you send the system back to repair, please try it on other computer if you have an access to it, just to make sure the PC parallel port and the port configurations are correctly setup.

For Repair/Replacement, please email to: nmiproduction@newmicros.com to obtain an RMA # and instruction for return.