[En-Nut-Discussion] Problems with MMC cards on Ethernut 3.0e

[Ole Reinhardt]

Hi Harald,

> I tried NPL v3 with the current trunk and an rather old MMC (not
> SDCard). This worked immediately without any problem. The card had been
> newly formatted with FAT (not FAT32) on a Windows PC.

So I'm currently using NPL v5

> Anyway, I'll use other NPL versions and SD-cards to reproduce the problem.

Thanks!

> Note, that there are 2 known bugs with Ethernut 3.0E and memory cards:
> 
> http://www.ethernut.de/en/hardware/enut3/enut30e.html

I Just added a 10µF capacitor in parallel to C5. The shortcut in the WP
line does not bother me (it's switched off anyway) and the shortcut
between shield and DGND should not be harmfull, should it?

Btw: I had the same problem with both MMC drivers (NPL directly and
using NPL SPI). In both cases some NOPs helped out. If I remove them,
the most significant bit in the received bytes is set from time to
time. 

Example:

I expect to read

00 00 00 00 00 00 00 00 00 00 00 00 00 00 ... 00

I readsomthing similar to:

00 80 00 00 00 80 00 80 00 00 00 00 00 80 ... 00

When adding the NOPs everything is ok.

Bye,

Ole


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