Re: Micro-SD card initialisation-problem


"R.Wieser" <address@xxxxxxxxxxxxx> wrote in message
news:48819d16$1$14351$e4fe514c@xxxxxxxxxxxxxxxxx
Hello rickman,

When you use a slow clock edge it become sensitive to
even a slight amount of ground bounce or other noise.

You've described a problem that I can't see and can't check for. What am
I
supposed to do with it ? Give up ? :-\

Regards,
Rudy Wieser

Do a differential diagnosis: hook up a schmittrigger buffer in the clock
line, very close to the card, and see if it makes a difference. If it does,
the clock edge is a problem, else not. Also keep the GND and VCC connection
between card and buffer short, and the buffer (and card!!!) supply lines
well decoupled: 100 nF should do, but check for VCC noise with your scope.
And yes, an 80 MHz scope is enough.

Arie de Muynck


.

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