Le code suivant que j'ai trouve sur playground fonctionne, il utilise le spi sans passer par la librairie, il ecrit 256 blocks et lit les 256 block en boucle donc je confirme un bug de la librairie sdfatlib pour le mega2560.
Teste sur une carte sd de 512 Mo
/*
Basic instructions for recording data in an SD Card in native mode
The SD card (3.3 V) must be properly interfaced to Arduino (5 V)
The typical procedure is:
Initialize SPI
Initialize SD Card
START
-Blank vector of data (vBlock)
-Record data in vector of data
-Copy data from vector to CSD card
GOTO START
At your convenience:
-Copy data from CSD card to vector of data
-Read data from vector
Starting from there, you will have to build your own file system...
Useful links
How to Use MMC/SDC
http://www.retroleum.co.uk/mmc_cards.html
Mixed-signal and digital signal processing ICs | Analog Devices
No warranty, no claims, just fun
Didier Longueville invenit et fecit February 2010
*/
// Ports
int PIN_CS = PINB0; // chip select
int PIN_MOSI = PINB2; // master out slave in
int PIN_MISO = PINB3; // master in slave out
int PIN_CLOCK = PINB1; // clock
/********************** SPI SECTION BELOW **********************/
// SPI Variables
byte clr; // dummy variable used to clear some of the SPI registers
byte spi_err; // SPI timeout flag, must be cleared manually
// send an SPI command, includes time out management
// returns spi_err: "0" is "no error"
byte spi_cmd(volatile char data) {
spi_err = 0; // reset spi error
SPDR = data; // start the transmission by loading the output byte into the spi data register
int i = 0;
while (!(SPSR & (1<<SPIF))) {
i++;
if (i >= 0xFF) {
spi_err = 1;
return(0x00);
}
}
// returned value
return(SPDR);
}
// initialize SPI port
void spi_initialize(void) {
SPCR = (1<<SPE) | (1<<MSTR); // spi enabled, master mode
clr = SPSR; // dummy read registers to clear previous results
clr = SPDR;
}
/********************** SD CARD SECTION BELOW **********************/
// SD Card variables
#define blockSize 512 // block size (default 512 bytes)
byte vBlock[blockSize]; // set vector containing data that will be recorded on SD Card
byte vBuffer[16];
#define GO_IDLE_STATE 0x00 // resets the SD card
#define SEND_CSD 0x09 // sends card-specific data
#define SEND_CID 0x0A // sends card identification
#define READ_SINGLE_BLOCK 0x11 // reads a block at byte address
#define WRITE_BLOCK 0x18 // writes a block at byte address
#define SEND_OP_COND 0x29 // starts card initialization
#define APP_CMD 0x37 // prefix for application command
// Send a SD command, num is the actual index, NOT OR'ed with 0x40.
// arg is all four bytes of the argument
byte sdc_cmd(byte commandIndex, long arg) {
PORTB &= ~(1<<PIN_CS); // assert chip select for the card
spi_cmd(0xFF); // dummy byte
commandIndex |= 0x40; // command token OR'ed with 0x40
spi_cmd(commandIndex); // send command
for (int i=3; i>=0; i--) {
spi_cmd(arg>>(i*8)); // send argument in little endian form (MSB first)
}
spi_cmd(0x95); // checksum valid for GO_IDLE_STATE, not needed thereafter, so we can hardcode this value
spi_cmd(0xFF); // dummy byte gives card time to process
byte res = spi_cmd(0xFF);
return (res); // query return value from card
}
// initialize SD card
// retuns 1 if successful
byte sdc_initialize(void) {
// set slow clock: 1/128 base frequency (125Khz in this case)
SPCR |= (1<<SPR1) | (1<<SPR0); // set slow clock: 1/128 base frequency (125Khz in this case)
SPSR &= ~(1<<SPI2X); // No doubled clock frequency
// wake up SD card
PORTB |= (1<<PIN_CS); // deasserts card for warmup
PORTB |= (1<<PIN_MOSI); // set MOSI high
for(byte i=0; i<10; i++) {
spi_cmd(0xFF); // send 10 times 8 pulses for a warmup (74 minimum)
}
// set idle mode
byte retries=0;
PORTB &= ~(1<<PIN_CS); // assert chip select for the card
while(sdc_cmd(GO_IDLE_STATE, 0) != 0x01) { // while SD card is not in iddle state
retries++;
if (retries >= 0xFF) {
return(NULL); // timed out!
}
delay(5);
}
// at this stage, the card is in idle mode and ready for start up
retries = 0;
sdc_cmd(APP_CMD, 0); // startup sequence for SD cards 55/41
while (sdc_cmd(SEND_OP_COND, 0) != 0x00) {
retries++;
if (retries >= 0xFF) {
return(NULL); // timed out!
}
sdc_cmd(APP_CMD, 0);
}
// set fast clock, 1/4 CPU clock frequency (4Mhz in this case)
SPCR &= ~((1<<SPR1) | (1<<SPR0)); // Clock Frequency: f_OSC / 4
SPSR |= (1<<SPI2X); // Doubled Clock Frequency: f_OSC / 2
return (0x01); // returned value (success)
}
// clear block content
void sdc_clearVector(void) {
for (int i=0; i<blockSize; i++) {
vBlock = 0;
- }*
}
// get nbr of blocks on SD memory card from
long sdc_totalNbrBlocks(void) {
- sdc_readRegister(SEND_CSD);*
- // compute size*
- long C_Size = ((vBuffer[0x08] & 0xC0) >> 6) | ((vBuffer[0x07] & 0xFF) << 2) | ((vBuffer[0x06] & 0x03) << 10);*
- long C_Mult = ((vBuffer[0x08] & 0x80) >> 7) | ((vBuffer[0x08] & 0x03) << 2);*
- return ((C_Size+1) << (C_Mult+2));*
}
// read SD card register content and store it in vBuffer
void sdc_readRegister(byte sentCommand) {
- byte retries=0x00;*
- byte res=sdc_cmd(sentCommand, 0);*
- while(res != 0x00) {*
- delay(1);*
- retries++;*
- if (retries >= 0xFF) return; // timed out!*
- res=spi_cmd(0xFF); // retry*
- } *
- // wait for data token*
- while (spi_cmd(0xFF) != 0xFE);*
- // read data*
- for (int i=0; i<16; i++) {*
vBuffer = spi_cmd(0xFF);
* }*
* // read CRC (lost results in blue sky)*
* spi_cmd(0xFF); // LSB*
* spi_cmd(0xFF); // MSB*
}
// write block on SD card
// addr is the address in bytes (multiples of block size)
void sdc_writeBlock(long blockIndex) {
* byte retries=0;*
while(sdc_cmd(WRITE_BLOCK, blockIndex * blockSize) != 0x00) {
* delay(1);*
* retries++;*
* if (retries >= 0xFF) return; // timed out!*
* }*
* spi_cmd(0xFF); // dummy byte (at least one)
_ // send data packet (includes data token, data block and CRC)_
_ // data token*_
* spi_cmd(0xFE);
_ // copy block data*_
* for (int i=0; i<blockSize; i++) {*
spi_cmd(vBlock*);
_ }
// write CRC (lost results in blue sky)_
spi_cmd(0xFF); // LSB*
* spi_cmd(0xFF); // MSB*
* // wait until write is finished*
* while (spi_cmd(0xFF) != 0xFF) delay(1); // kind of NOP*
}
// read block on SD card and copy data in block vector
// retuns 1 if successful
void sdc_readBlock(long blockIndex) {
* byte retries = 0x00;*
byte res = sdc_cmd(READ_SINGLE_BLOCK, (blockIndex * blockSize));
* while(res != 0x00) {*
* delay(1);*
* retries++;*
* if (retries >= 0xFF) return; // timed out!*
* res=spi_cmd(0xFF); // retry*
* }*
* // read data packet (includes data token, data block and CRC)*
* // read data token*
* while (spi_cmd(0xFF) != 0xFE);
_ // read data block*
* for (int i=0; i<blockSize; i++) {
vBlock = spi_cmd(0xFF); // read data
}
// read CRC (lost results in blue sky)_
spi_cmd(0xFF); // LSB*
* spi_cmd(0xFF); // MSB*
}
// print vector of data
void sdc_printVectorContent(void) {
* for (int i=0; i<blockSize; i++) {*
* Serial.print("0x");*
_ if (vBlock <= 0x0F) Serial.print("0");
Serial.print(vBlock*, HEX);
Serial.print(" ");
// append crlf to each line of 16 bytes*
* if (((i+1) % 16) == 0) Serial.println();
}
Serial.println();
}
/********************* MAIN ROUTINES SECTION BELOW /
void setup() {
// Set ports
// Data in_
DDRB &= ~(1<<PIN_MISO);
_ // Data out_
DDRB |= (1<<PIN_CLOCK);
DDRB |= (1<<PIN_CS);
DDRB |= (1<<PIN_MOSI);
_ // Initialize serial communication
Serial.begin(9600);
// Initialize SPI and SDC_
spi_err=0; // reset SPI error
spi_initialize(); // initialize SPI port
* sdc_initialize(); // Initialize SD Card*
* Serial.print(sdc_totalNbrBlocks(), DEC);
_ Serial.println(" blocks");
}
void loop() {
// This is just an example*
* Serial.println("Writing blocks...");
for (int b=0; b<255; b++) {
Serial.print("Writing block ");
Serial.println(b, HEX);
for (int i=0; i<blockSize; i++){
vBlock = b; // write incremental data
}_
sdc_writeBlock(b); // copy vector of data on SD card*
* }*
* Serial.println("Reading blocks...");*
* for (int b=0; b<255; b++) {*
* Serial.print("Reading block ");*
* Serial.println(b, HEX);*
* sdc_readBlock(b); // copy SD card block of data in vector of data*
* sdc_printVectorContent(); // print vector of data content*
* }*
}
[/quote]
