Atmega16 and MMC

In ATMega16, I want to ask how to use SPI with a MMC card.

I have seen that there are 4 pins in ATMega16 which implements SPI. They are


For a MMC card, the 4 pin assignments are

1 CS 2 Din 5 SCK 7 Dout

Is the SS pin of ATmega16 connected to CS of MMC or else?


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"terry" skrev i meddelandet news:


When You talk to an MMC card, the CPU is the Master and the Card is a slave. The /SS signal is slave select and is used when the CPU is a slave. You can connect any I/O port to the CS of the card. If you have another Master on the bus it needs to be anything but /SS.

Best Regards,
Ulf Samuelsson
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Ulf Samuelsson

I have connected /ss to /cs (pin 1) of mmc card and it works.

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Yes, but as a master, the SS pin of the Mega16 is just an I/O pin which you set yourself. So you could have used any output for that. The only dedicated function of the SS pin is when it is used as an input when the SPI interface is programmed to be a slave.


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Meindert Sprang

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