This is a repair log for D0 MCEN boards, starting 2/5/06.

JTAG Debugging software installed on Linux machine. Run as ./jtag_shell. Useful commands:

 R  JTAG Reset
 L  Measure chain length
 I  Measure total instruction register length
 T  set to BYPASS, toggle TDI-TDO on and off
 M  toggle TMS on and off

Board 15

JTAG chain broken. Unplugged all Rx and Physics board.

• Look at TCK, TMS on 10p Rx conn. All OK.
• U47-20 OK, U47-21 different pattern

Now see TMS, TCK, TDI ok into VME FPGA. TDO is dead. All 3 FPGAs are quite hot. Temp probe says 50+ deg C after 5 minutes on.

'Replace all 3 FPGAs?

Board 4

JTAG chain broken. Try standard JTAG init... genesis and tpa ok, main chain is broken.

Remove Rx#1 and Rx#12. No TDI at Rx#1 (TMS, TCK okay).

Take off Physics board and Tx#1 cable.

FPGA_TDI (VME FPGA pin 176) - OK TDO (pin 189) Dead. (TCK, TMS ok)

'Replace VME FPGA?

Board 19

JTAG chain broken. Try standard JTAG init... genesis and tpa ok, main chain is broken.

Remove Rx#1. No TDI @ Rx#1. No TDI at VME FPGA.

Remove Physics board. Now VME FPGA TDI is ok. No TDI @ Rx#1. TDI, TDO @ VMEchip, ListsChip?.

Errorchip has no TDO (TDI OK). TCK OK. TMS OK.

'Replace Error FPGA?

Board 25

JTAG chain broken. Try standard JTAG init... genesis and tpa ok, main chain is broken. Oops. Was missing two Tx. Found a couple and plugged them in.

JTAG Chain now OK.

Programming errors on Lists chip (consistently and VME chip (sometimes).

'Replace VME and Lists FPGAs?