[PIC] MMC interfacing with PIC

[soft_learn]

Hi,

I am trying to interface a Memory Card for storing and extracting data from the card.
But being new to Memory Card interfacing i want to know about the basic about the registers used to store data and read data from Memory Card. I know that there are libraries which can help interfacing easy but i wanna start from the basic. Does any one here knows about the registers help me out ?

 

[doraemon]

Hello!

Which registers are you talking about? CPU registers?
If you program in C, you don't have to care about registers, just setup a SPI
(By the way, you want to communicate in SPI, right??) and initialise the card.

Then once your SDCard.c / SDCard.h works, you can try to make a file system.
It's a very good exercise.

Dora.

 

[FvM]

You can refer to the MMC and SDcard specification available on the Internet, see the links at the end of these articles.
https://en.wikipedia.org/wiki/MultiMediaCard
https://en.wikipedia.org/wiki/Secure_Digital

 

[soft_learn]

yea i know in mikroc there are in-built libraries which help programming easy but i want to know which are registers used to read and write data to Memory card. Like in GSM TXREG register is used to send data from gsm. So wanna know about registers which help in reading and writing of data. I don't wanna use the libraries for Memory card interfacing.

 

[doraemon]

Hello!

So you are talking about CPU register needed to access SD card?
- Setup a SPI connection (see the docs of the PIC you are using for specific registers).
- Then use the code of FvM's links.

For MSP430, for example, you can send data by SPI by writing UCxxTX = my_byte;
and the byte is sent immediately.
For receiving, it's like this: my_byte = UCxxRX;
Now there are myriads of subtleties depending on whether you send / receive byte
by byte (I would recommend you to start like this), or using DMA which is more tricky
but more efficient.

PS: Look around to find some code, I am sure there is. I'm an absolute beginner
with PIC, and I found this:
**broken link removed**
with which I could write an LCD graphic interface (Pic32).

Dora.