- Atmega16 and MMC
- Posted by terry on November 7th, 2004
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!
- Posted by Ulf Samuelsson on November 7th, 2004
"terry" <leonlai2k@yahoo.com> skrev i meddelandet
news:9904d48.0411062226.25c4fb5d@posting.google.co m...
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
- Posted by terry on November 8th, 2004
I have connected /ss to /cs (pin 1) of mmc card and it works.
- Posted by Meindert Sprang on November 8th, 2004
"terry" <leonlai2k@yahoo.com> wrote in message
news:9904d48.0411080111.5bf02df@posting.google.com ...
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
