MPC555 bug
"bclairc (sent by Nabble.com)" <[email protected]>
| Newsgroups | gmane.comp.hardware.motorola.microcontrollers |
|---|---|
| Message-ID | <[email protected]> |
Hi,
I have got a strange phenomenon on a board and i have searching for days without solutions; this board is not new (exists for 2 years) and the problem is appeared 3 weeks ago.
At the power up of the board, it could occurs (statistic is around 1 for 500 power up) that several outputs of the MPC are tied to 0V and stay at this level. In particular all GPCM outputs which occur conflicts, or TouCAN outputs which become dominant.
In this case, HRESET is kept to 0V without effect.
I have tried to activate the PORESET but without success.
I have tried to cut VDDL, VVDI, VDDSYN, KAPWR but when i put them back the problem is still there.
I have cut all previous supplies plus VVDH and VVDA : same results.
The only supply i had not cut is VDDSRAM....
The only way to exit from this position is to cut all supplies of my board !
I have thought of a possible latch up phenomenon but do not understand why it occurs now, after several monthes of good working. The board design is still the same.
Could I have an internal MPC problem which can exist with these results ?
Thanks for your help,
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