Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

JTAG Chain problem - no device detected (Tried with multiple boards)

Hi everyone, I'm doing some work with custom cyclone III boards and am in the process of trying to program the device using a JTAG port and a USB Blaster cable. The boards were used last yea...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

The computer to Usb-Blaster communication looks like it's working (the error message would be something like "bad hardware" if it wasn't).

But there could be a problem on the far side of the USB-Blaster. The common faults are TDO stuck high or low, but the jtag chain debugger can normally diagnose those (as can jtagconfig -d).

JTAG chain broken means that data shifted out of TDI did not come back through TDO. This could be caused by open circuit on any of the jtag lines but I suspect TDI. If you have a scope then I suggest checking for activity on TCK, TMS, TDI and TDO.