DOM MB V5 Diagnosis page

Board ID:

V5.0L 000695

Source:

Azriel Goldschmidt

Symptoms:                            

August 31: Intermittant communications.  No More ON-ALL after cold.
October 10: Intermittant boot cold

Analyst(s):

Thorsten Stezelberger/gtp

Analysis Procedure(s):

August 31: Observation of nPOR, nSTATUS, nCONFIG, CONF_DONE, and other related lines of the Configuration memory and EPXA4.  A race condition was suggested by analysis of the discription of bootin in the EPC8  and EPXA4 data sheets.   A change in the CPLD code,  holding low the nCONFIG, and nSTATUS lines for the required number of cycles after nPOR goes true,  cured the problem.  This particular board was the Reference board, held back in case further debugging was necessary
STF OK @ -45°C, and at +65°C
October 10;  This board was found to be running the old CPLD firmware (25, instead of 29).  Installing the latest CPLD firmware restored proper cold boot behavior.
No boot failures observed during 500 reboot tests every 2 minutes, while sweeping the temperature from -45°C to +65°C every 90 minutes.
Low temperature (-40°C to -75°C) profile not performed.

Root cause:

Race condition during booting.

Mitigation:

Change CPLD code to control booting explicitly.

Disposition:

Mainstream after testing.

Any Other Information:

Traveler August 31
Traveler October 27