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Altera_Forum's avatar
Altera_Forum
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18 years ago

Quartus Can't scan device

I have a custom PCB with the altera epm7064s chip. The chip was programmed and the circuit worked but after a little while one of the capacitors used for a 555 timer blew. Since then the timer output has been a little distorted (as expected) but when the button to trigger the altera chip is pressed nothing happens. So I plugged the byteblaster back in, opened Quartus to check the program. When I clicked auto detect, i get the following message:

''Unable to scan device chain. Can't scan JTAG chain."

I believe something may have happened to the chip when the capacitor blew. Is this a correct assumption and if so is there anyway of verifying this?

Thanks

Joe

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    18 years ago

    Hello,

    operation of the JTAG programming and test interface should not depend on other pin states exept power supply. Assuming your JTAG programming adapter is known operational, JTAG interface uses no other parts than connector and pull-up/-down resistors (most likely), then either the power supply is missing or the device is defective.

    Regards

    Frank
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    18 years ago

    Hi Joe,

    maybe it is possible for you to measure the TDI input and the TDO out of your Max device, when the programmer tries to scan the chain. When you couldn't see the data

    coming out of TDO you should check the power supply.

    Regards

    Gerd