HELP!!!! - UF32 Can't make SDCLK signal work

[Fandur]

I read the manuals, the reference design code, everything. I just can't make this thing work. All I want is the absolut minimum settings to get a CMD0 out at the 100 pin version. I have been squeezing my brain out trying to make this work, so far unsuccesfully.

This are the simptoms:

- I configure the SDCLK line as a GPIO and drive it on and off sucessfully. (no short circuit there)

- When I turn on the SD module and send a CMD0 i get this clock signal:

CH1=SDCLK

CH2=SDCMD

The outcome is the same no matter if i plug the SD card or not. I'm guessing is some sort of pin redirection problem or something like that because the other signals are ok. As I said earlier the pin works fine when I use it as GPIO.

  I just don't know what is going on. Please help!

[imajeff]

I'm new to the SDcard interface, but I was wondering if it's supposed to have a pullup resistor on SDCLK

[glork]

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Fandur wrote:

I read the manuals, the reference design code, everything. I just can't make this thing work. All I want is the absolut minimum settings to get a CMD0 out at the 100 pin version. I have been squeezing my brain out trying to make this work, so far unsuccesfully.

This are the simptoms:

- I configure the SDCLK line as a GPIO and drive it on and off sucessfully. (no short circuit there)

- When I turn on the SD module and send a CMD0 i get this clock.

Hello Fandur.
I have some experience working with the 'UF32 and CF cards. I don't know if my experience will cover your problem but if you can give more details on your application and perhaps a pseudo-code snippet of what you're doing I'll look it over.
ron

[Fandur]

Hi glork,

           Try this out and tell me what do you see at the SDclock pin. I dont think i'm missing any register configuration, if i do please tell me . I'm working with the 100 pin version so i don't need to set the MODRR.

          Thank you very much for your time. If you need more information just ask. I'm guessing is some sort of pin redirection problem or something like that.

Thanks

Message Edited by Fandur on 03-17-200609:17 AM

Message Edited by Fandur on 03-17-200609:18 AM

[glork]

Hi Fandur.
Sorry, I don't use C but I think I understand most of what your snippit does. The doc doesn't say much about initializing the interface (with the UF32 thats not a big supprise).
I have these comments:
1. You can read the SDKON bit in the SDSTAT reg.; 1 means SDCLK is running, 0 means it isn't.
2. I know the doc may imply its un-necessary but try making the SDCLK pin an output before initializing the SD interface. I tend to not believe everything the doc implies.
3. I couldn't tell from your code or from the doc but is it necessary for the interface to see the card plugged in before the clock will work?
One of the port pins (data-3?) is used for card-detect.

In general, I've found the UF32 to be extremely powerful and quite well behaved for my application but I can relate this to you:
I selected the UF32 because it has a built-in CF interface. We started our using code segments from Freescale's ap-note to work with the cards. We found that the operation of the CF interface interfered with port pins that WERE UNRELATED TO THE CF INTERFACE. I finally threw all that away and wrote a CF driver using GPIO and bit-banging. It works great. So much for the CF interface.
ron