My CPLD stopped working! Can't access JTAG chain

[Fester]

My CPLD stopped working!

I have a MAX II Micro board with MAX II EPM2210F324C3, i got it in my school lab and it worked fine a few months ago and now i tried to download a program from quartus on it and i get the followin error messages.
Error: Can't access JTAG chain
Error: Operation failed.
I am using the usb blaster.I remember programming it without connecting a power source to the cpld but i connected one and grounded the CPLD just to make shure that wasnt the problem, but it still failed.Also when i click on the "auto detect" i get the following message unable to scan device chain.Cant scan JTAG chain.I dont think the usb cable is broken cuz i can also connect the cpld directly to my computer w/o using the usb cable and still get those errors.
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[banjo]

My CPLD stopped working!

Does the CPLD get hot? Can you measure its current draw? Is it pulling more or less current than normal? The JTAG message is a generic one. All it means is that no valid data was seen on the TDO line. This could be caused by a bad CPLD, or a bad USB cable, or a misconnected cable, or a incorrect jumper setting on the micro board, or a sofware error. The list is endless.

Do you have a school mate who could try to program your board on their PC? Could you try to program a school mate's micro board with your PC? (This is what is known as half-split troubleshooting, divide the potential trouble in half.)

I am not really familiar with Altera. However, in Xilinx you have to be very careful. If the Xilinx Impact software fails the JTAG chain, it can lock up the software and give continual JTAG errors until you exit the software and restart it. For example, if I attach the cable wrong and the JTAG chain fails to detect, I have to fix the cable error AND restart the software. Just fixing the cable error will still give errors because the software is locked up.

 

[FvM]

My CPLD stopped working!

No original &#65ltera USB Blaster is sourcing a supply voltage to a device, cause it's designed to support a variable logic supply of 1.8 to 5.0 V. The only explanation is, that you had a user modified exemplar at your school lab.