STM CircleOS forum / SD Card Read/Write without circle OS

rob1 · 2009-06-01 10:43:50

Hi there,
so first i better say that i´m very new to programming with C. so don´t expect too much

So the problem i have is, that i want to read and write data that i get from my sensors to an sd card. I use the Stm32 Primer 2 but witout Circle OS. For that reason i included the sdcard class und header file from circle OS to my project. That far so well. Now i want to use the read and write methods from that class but don´t understand how that works.
I use an 16gb micro sd formated fat32 with 512 Byte blocksize.
Is it advisible to use fat 32? Also could read/write raw?! Maybe i don´t need any file system... one big file is enough

First i call up the init:
SD_Init();

Then i try to write an block like that:
char test[6];
test[0]='h';
test[1]='e';
test[2]='l';
test[3]='l';
test[4]='o';
test[5]=0;
u16 blocksiz=512;
u32 addr=(u32)&test;
u32 startadr = ((u32)0x00000000);
SD_WriteBlock(startadr, &addr, blocksiz);

After that i want to read the same data with that:

u32 start=((u32)0x00000000);
char antwort[4096];
u32 buf=(u32)&antwort;
SD_ReadBlock(start, &buf,blocksiz);
antwort[6]=0;
printf_screen(antwort);

delayMS( 100 );

I get 6 chars on the screen but some signs i don´t understand. I get the same chars when i start reading at any other adress... So something i do very wrong

If anyone can help me, i would be very grateful.

repzak · 2009-06-01 11:00:00

Hello,

First think i se is you write the adress of addr to the file, not the content of addr..., you must remove the & in write block...

SD_WriteBlock(startadr, addr, blocksiz);

or i think

SD_WriteBlock(startadr, test, blocksiz);

It will proberly give a type warning..

For the read:
u32 start=((u32)0x00000000);
char antwort[4096];

SD_ReadBlock(start, antwort,blocksiz);
antwort[6]=0;
printf_screen(antwort);

When you have an array, the reference to the name (antwort) will give you automaticly the adress to the ram point, if you use antwort[0] it will give you the first data in the array

Hope that can help you a tlitle

Kasper

rob1 · 2009-06-01 11:21:48

First thannks for the fast answer.
The printf_screen methos requires a String which is the same like an char[] in C. That works like i did. If i add the antwort[0]='t'; for example:
u32 start=((u32)0x00000000);
char antwort[4096];
u32 buf=(u32)&antwort;
SD_ReadBlock(start, &buf,blocksiz);
antwort[0]='t';
antwort[20]=0;
printf_screen(antwort);

I get the "t" on the screen the sign after the t are unreadable...

If i leave the & or replace adr with test nothing really changes. Maybe the method description helps a little.

/*******************************************************************************
* Function Name : SD_WriteBlock
* Description : Allows to write one block starting from a specified address
* in a card.
* Input : - addr: Address from where data are to be read.
* - writebuff: pointer to the buffer that contain the data to be
* transferred.
* - BlockSize: the SD card Data block size.
* Output : None
* Return : SD_Error: SD Card Error code.
*******************************************************************************/
SD_Error SD_WriteBlock(u32 addr, u32 *writebuff, u16 BlockSize)
{

/*******************************************************************************
* Function Name : SD_ReadBlock
* Description : Allows to read one block from a specified address in a card.
* Input : - addr: Address from where data are to be read.
* - readbuff: pointer to the buffer that will contain the
* received data
* - blocksize: the SD card Data block size.
* Output : None
* Return : SD_Error: SD Card Error code.
*******************************************************************************/
SD_Error SD_ReadBlock(u32 addr, u32 *readbuff, u16 BlockSize)
{

so any other ideas?

repzak · 2009-06-01 12:27:55

Hello,

char test[6];
test[0]='h';
test[1]='e';
test[2]='l';
test[3]='l';
test[4]='o';
test[5]=0;
u16 blocksiz=512;
u32 startadr = ((u32)0x00000000);
SD_WriteBlock(startadr, &test[0], blocksiz);

------------------------------------------------------------

u32 start=((u32)0x00000000);
char antwort[4096];
SD_ReadBlock(start, &antwort[0],blocksiz);
antwort[6]=0;
printf_screen(antwort);

I think that must work, you sure the card is initlized correctly, think you get a value back from init_sd()?

Kasper

rob1 · 2009-06-02 01:16:14

Hello kasper,
thanks for the hint with the errors.
I catched them but init throws SD_OK but read and write not. They both throw an SD_CMD_RSP_TIMEOUT Error which means Comand response timeout. What can that mean?

I will try to localize the error more detailed...

but if anybody can help....

# 1 2009-06-01 10:43:50 SD Card Read/Write without circle OS

SD Card Read/Write without circle OS

# 2 2009-06-01 11:00:00 SD Card Read/Write without circle OS

Re: SD Card Read/Write without circle OS

# 3 2009-06-01 11:21:48 SD Card Read/Write without circle OS

Re: SD Card Read/Write without circle OS

# 4 2009-06-01 12:27:55 SD Card Read/Write without circle OS

Re: SD Card Read/Write without circle OS

# 5 2009-06-02 01:16:14 SD Card Read/Write without circle OS

Re: SD Card Read/Write without circle OS

Board footer