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[Q]Strange behavior in reading Compact Flash card

Started by Unknown May 29, 2007
Dear all,

I am having a problem when I try to read CF card. I am using an ARM7
and the CF card is in Memory Mapping mode with 16-bit data bus width.
>From the CF specification 4.0, it said that to access the data
register in CF card, pull down -CE1 and -CE2, and the 512 bytes can be read out consecutively. But when I tried to do this, every second read is the same as its previous read such like Correct one : B0 B1 B2 B3 B4 B5 ...... What I got : B0 B1 B0 B1 B2 B3 B2 B3 .... So I have to read twice and discard one of them to obtain the correct data. The CF card I am using is Transcend 512MB, I haven't tested Sandisk's. Does anybody experience the same thing? Thanks.
Ummmm... Sandisk 1G CF card performed normally, I guess something
wrong (maybe timing problem) !

Ummmm... Sandisk 1G CF card performed normally, I guess something
wrong (maybe timing problem) !