NIOS II JTAG Download errors

jdhar,

It sounds like you are on the right track to debug this problem by isolating the DDR peripheral.

Since you mentioned SignalTap works (JTAG is probably not the problem), the issue could be how the DDR chip interfaces to the Avalon switch farbic through the DDR controller.

Have you used SignalTap to probe the DDR pins and the DDR controller Avalon interface signals? If the DDR controller is getting some bad signals from the DDR ram (i.e. poor solder connection, mis-wired DDR RAM connections to DDR controller), it could be sending random signals into Avalon perhaps tying up the whole system.

Regards,

-ATJ