8/16/32 bit JEDEC probe

Michel Stempin michel.stempin at telecom-design.com
Fri Sep 12 18:03:22 EDT 2008

Hi list,

I have an interesting case to submit.

I have a SystemBase ARM9 (AT91SAM9260) Eddy-CPU-V2 that can be populated
with either a 32MB SST 39VF3201 (Mfr: 0x00bf, Id: 0x235b) or a 64MB EON
EN29LV640B (Mfr: 0x007f, Id: 0x22cb) part. Mine has the SST part.

As none of these chips were defined in jedec_probe.c, I defined them

However, when the probe is done, an SST 49LF080A (Mfr: 0x00bf, Id:
0x005b) is found instead of my SST 39VF3201...

What is remarkable is that both chips have the same LSB Id!

My conclusion is that the less discriminating 8-bit device detection has
precedence over the more discriminating 16-bit device.

Shouldn't this be the other way around (ie. first detect 32, then 16,
then 8 bit devices)?

If I comment the SST 49LF080A definition, everything works as expected.

Best regards,

Michel Stempin

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