Library mmcsd.c

Dave_25152 · Joined: 11 Dec 2010 Posts: 60

Friends I am trying to connect to a PIC16F88 an MMC / SD. The SD card has the function of serving as EEPROM.

When I compile the program, there is an error:

«int g_mmcsd_buffer[MMCSD_MAX_BLOCK_SIZE]» - data item too big

However if you change:

«#define MMCSD_MAX_BLOCK_SIZE 512»

by:

«#define MMCSD_MAX_BLOCK_SIZE 64»

The program already compiles and shows no error.

I'm not very experienced in this and I'm trying to teach myself. I do not know what I mean to change this value. Something negative will happen to the project?

If possible, I would appreciate a simple explanation of this matter.

My thanks!

Regards

Ttelmah · Joined: 11 Mar 2010 Posts: 19509

Problem is memory.
The MMC/SD card, 'talks' in blocks of 512 bytes. This is the 512 value. So, 'no', you can't change this. For use with a PIC, you need to be able to buffer one whole block at a time. Basically your chip has too little RAM to do this. Just 368 bytes.

Best Wishes

Dave_25152 · Joined: 11 Dec 2010 Posts: 60

OK.

Very savvy! Thanks a lot.

Yours sincerely,
David Martins