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errata CPU10 for MPC855 ?

U-Boot-Users Steven Scholz 1 participant 1 message Feb 5, 2003

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Hi there,

I just stumbled over an old errata:

CPU10. Possible Excess Current Consumption in Deep Sleep Mode.

Certain nodes of the multiplier hardware are not initialized at reset, and may thus result in non-destructive internal contention. As a result, if the processor is put into Deep Sleep mode without first putting the multiplier into a known state, current consumption in this mode may be higher than expected.

Workaround:
Execute a mullw instruction at any point after reset; this will put the internal nodes in an orderly state. Deep Sleep mode may then be entered at any time thereafter.

The only mullw's I found in post/cpu/asm.S.

I am not sure, but I guess these functions will only get called if I enable POST!?

So should we put "a mullw instruction at any point after reset"???

Thanks,

Steven