"terry" <leonlai2k@yahoo.com> wrote in message
news:9904d48.0411080111.5bf02df@posting.google.com...
> > 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.
>
> I have connected /ss to /cs (pin 1) of mmc card and it works.

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.

Meindert

> 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.

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

"terry" <leonlai2k@yahoo.com> skrev i meddelandet
news:9904d48.0411062226.25c4fb5d@posting.google.com...
> 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
>
> SS, MOSI, MISO, SCK.
>
> 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?
>
> Thanks!

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   ulf@a-t-m-e-l.com
This is a personal view which may or may not be
share by my Employer Atmel Nordic AB

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 

SS, MOSI, MISO, SCK.

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?

Thanks!