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Hard to read/write MMC (no response)

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SISWANTO

SISWANTO

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Hi all,
I am wrating code for read/write Multimedia card (MMC), I use paralel port first before I use microcontroller. I already use converter 3.3volt to 5volt and 5volt to 3.3volt. when I do initialize, there is no response from MMC. The MISO (Master Input Slave Output) pin on tri-state all time. Is there anyone have done write code?? please, I need your help..

PS:My source code attached.

Salam
Sis
 

Hello!
I am having the same problem as you, but I am using an AVR 8535 with the SPI mode, I have a code that is not working but I think that the main problem is related to some clock cycles that you need before you send the CMD0.
 

May be this linker can hlep you
h**p://www.compsys1.com/workbench/On_top_of_the_Bench/MMC_Project/mmc_project.html
 

Thanks dabi
But actually I am developing my proyect. I have seen a lot of proyects but none of them have been of great help.
The thing is that you need to send some clock cycles to the slave device, and when generating the clock cycles I think that the device might take them as a zero comand, and that would be returning to the begining, the reset sequence. On the other hand, the AVR 8535 stops sending clock cycles after the transmission of a single byte, so I have to do some sutff in order to send the clock cycles, wich leads us to the point that the MMC will take it as a zero comand.

Any ideas?
 

I have the same problem, but i am using the AT89C5132 uC and MMC mode (instead of SPI mode). when i send CMD0 and CMD1 after it, i receive OCR correctly, but with the busy bit cleared (card is busy). and when i send CMD1 againn there is no response from the card, it seems that the card is bsuy for ever.

Any one could help me??:|
 

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