flash_sdcard.c
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/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // general utilities
/* STM32 (including CM3) libraries */
#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
#include <libopencm3/stm32/rcc.h> // real-time control clock library
#include <libopencm3/stm32/gpio.h> // general purpose input output library
#include <libopencm3/stm32/spi.h> // SPI library
#include "global.h" // global utilities
#include "flash_sdcard.h" // SD card header and definitions
#define FLASH_SDCARD_SPI 1
static bool initialized = false;
static uint32_t n_ac = 8;
static bool sdsc = false;
static uint64_t sdcard_size = 0;
static uint32_t erase_size = 0;
static const uint8_t crc7_table[] = {
0x00, 0x09, 0x12, 0x1b, 0x24, 0x2d, 0x36, 0x3f, 0x48, 0x41, 0x5a, 0x53, 0x6c, 0x65, 0x7e, 0x77,
0x19, 0x10, 0x0b, 0x02, 0x3d, 0x34, 0x2f, 0x26, 0x51, 0x58, 0x43, 0x4a, 0x75, 0x7c, 0x67, 0x6e,
0x32, 0x3b, 0x20, 0x29, 0x16, 0x1f, 0x04, 0x0d, 0x7a, 0x73, 0x68, 0x61, 0x5e, 0x57, 0x4c, 0x45,
0x2b, 0x22, 0x39, 0x30, 0x0f, 0x06, 0x1d, 0x14, 0x63, 0x6a, 0x71, 0x78, 0x47, 0x4e, 0x55, 0x5c,
0x64, 0x6d, 0x76, 0x7f, 0x40, 0x49, 0x52, 0x5b, 0x2c, 0x25, 0x3e, 0x37, 0x08, 0x01, 0x1a, 0x13,
0x7d, 0x74, 0x6f, 0x66, 0x59, 0x50, 0x4b, 0x42, 0x35, 0x3c, 0x27, 0x2e, 0x11, 0x18, 0x03, 0x0a,
0x56, 0x5f, 0x44, 0x4d, 0x72, 0x7b, 0x60, 0x69, 0x1e, 0x17, 0x0c, 0x05, 0x3a, 0x33, 0x28, 0x21,
0x4f, 0x46, 0x5d, 0x54, 0x6b, 0x62, 0x79, 0x70, 0x07, 0x0e, 0x15, 0x1c, 0x23, 0x2a, 0x31, 0x38,
0x41, 0x48, 0x53, 0x5a, 0x65, 0x6c, 0x77, 0x7e, 0x09, 0x00, 0x1b, 0x12, 0x2d, 0x24, 0x3f, 0x36,
0x58, 0x51, 0x4a, 0x43, 0x7c, 0x75, 0x6e, 0x67, 0x10, 0x19, 0x02, 0x0b, 0x34, 0x3d, 0x26, 0x2f,
0x73, 0x7a, 0x61, 0x68, 0x57, 0x5e, 0x45, 0x4c, 0x3b, 0x32, 0x29, 0x20, 0x1f, 0x16, 0x0d, 0x04,
0x6a, 0x63, 0x78, 0x71, 0x4e, 0x47, 0x5c, 0x55, 0x22, 0x2b, 0x30, 0x39, 0x06, 0x0f, 0x14, 0x1d,
0x25, 0x2c, 0x37, 0x3e, 0x01, 0x08, 0x13, 0x1a, 0x6d, 0x64, 0x7f, 0x76, 0x49, 0x40, 0x5b, 0x52,
0x3c, 0x35, 0x2e, 0x27, 0x18, 0x11, 0x0a, 0x03, 0x74, 0x7d, 0x66, 0x6f, 0x50, 0x59, 0x42, 0x4b,
0x17, 0x1e, 0x05, 0x0c, 0x33, 0x3a, 0x21, 0x28, 0x5f, 0x56, 0x4d, 0x44, 0x7b, 0x72, 0x69, 0x60,
0x0e, 0x07, 0x1c, 0x15, 0x2a, 0x23, 0x38, 0x31, 0x46, 0x4f, 0x54, 0x5d, 0x62, 0x6b, 0x70, 0x79
};
static void flash_sdcard_spi_wait(void)
{
spi_send(SPI(FLASH_SDCARD_SPI), 0xffff); // send not command token (i.e. starting with 1)
}
static uint16_t flash_sdcard_spi_read(void)
{
spi_send(SPI(FLASH_SDCARD_SPI), 0xffff); // send not command token (i.e. starting with 1)
(void)SPI_DR(SPI(FLASH_SDCARD_SPI)); // clear RXNE flag (by reading previously received data (not done by spi_read or spi_xref)
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_TXE)); // wait until Tx buffer is empty before clearing the (previous) RXNE flag
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_RXNE)); // wait for next data to be available
return SPI_DR(SPI(FLASH_SDCARD_SPI)); // return received adat
}
static bool flash_sdcard_card_detect(void)
{
rcc_periph_clock_enable(RCC_SPI_NSS_PORT(FLASH_SDCARD_SPI)); // enable clock for NSS pin port peripheral for SD card CD signal
gpio_set_mode(SPI_NSS_PORT(FLASH_SDCARD_SPI), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set NSS pin as input to read CD signal
gpio_clear(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // pull pin low to avoid false positive when card in not inserted
return (0!=gpio_get(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI))); // read CD signal: is card is present the internal 50 kOhm pull-up resistor will override our 1 MOhm pull-down resistor and set the signal high (see section 6.2)
}
static void flash_sdcard_send_command(uint8_t index, uint32_t argument)
{
uint8_t command[5] = { 0x40+(index&0x3f), argument>>24, argument>>16, argument>>8, argument>>0 }; // commands are 5 bytes long, plus 1 bytes of CRC (see section 7.3.1.1)
uint8_t crc7 = 0x00; // CRC-7 checksum for command message
// send command
for (uint8_t i=0; i<LENGTH(command); i++) {
spi_send(SPI(FLASH_SDCARD_SPI), command[i]); // send data
crc7 = (crc7_table[((crc7<<1)^command[i])])&0x7f; // update checksum
}
spi_send(SPI(FLASH_SDCARD_SPI), (crc7<<1)+0x01); // send CRC value (see section 7.3.1.1)
}
static uint8_t flash_sdcard_command_response(uint8_t index, uint32_t argument, uint8_t* response, size_t size)
{
// send command token
gpio_clear(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS low to select slave and start SPI mode (see section 7.2)
flash_sdcard_spi_wait(); // wait for N_CS (min. 0, but it works better with 8 clock cycles) before writing command (see section 7.5.1.1)
flash_sdcard_send_command(index, argument); // send command token
// get response token R1
uint8_t r1 = 0xff; // response token R1 (see section 7.3.2.1)
for (uint8_t i=0; i<8 && r1&0x80; i++) { // wait for N_CR (1 to 8 8 clock cycles) before reading response (see section 7.5.1.1)
r1 = flash_sdcard_spi_read(); // get response (see section 7.3.2.1)
}
if (0x00==(r1&0xfe) && 0!=size && NULL!=response) { // we have to read a response
for (size_t i=0; i<size; i++) {
response[i] = flash_sdcard_spi_read(); // get byte
}
}
// end communication
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy (= transmission completed)
// wait for N_EC (min. 0) before closing communication (see section 7.5.1.1)
gpio_set(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS high to unselect card
// wait for N_DS (min. 0) before allowing any further communication (see section 7.5.1.1)
return r1;
}
static uint8_t flash_sdcard_read_block(uint8_t* data, size_t size)
{
if (size%2 || 0==size || NULL==data) { // can't (and shouldn't) read odd number of bytes
return 0xff;
}
uint8_t token = 0xff; // to save the control block token (see section 7.3.3)
for (uint32_t i=0; i<n_ac && token==0xff; i++) { // wait for N_AC before reading data block (see section 7.5.2.1)
token = flash_sdcard_spi_read(); // get control token (see section 7.3.3)
}
if (0==(token&0xf0)) { // data error token received (see section 7.3.3.3)
if (0==(token&0x0f)) { // unknown error
token = 0xff;
}
} else if (0xfe==token) { // start block token received (see section 7.3.3.2)
// switch to 16-bits SPI data frame so we can use use built-in CRC-16
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_TXE)); // wait until the end of any transmission
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy before disabling
spi_disable(SPI(FLASH_SDCARD_SPI)); // disable SPI to change format
spi_set_dff_16bit(SPI(FLASH_SDCARD_SPI)); // set SPI frame to 16 bits
SPI_CRC_PR(FLASH_SDCARD_SPI) = 0x1021; // set CRC-16-CCITT polynomial for data blocks (x^16+x^12+x^5+1) (see section 7.2.3)
spi_enable_crc(SPI(FLASH_SDCARD_SPI)); // enable and clear CRC
spi_enable(SPI(FLASH_SDCARD_SPI)); // enable SPI back
// get block data (ideally use DMA, but switching makes it more complex and this part doesn't take too much time)
for (size_t i=0; i<size/2; i++) {
uint16_t word = flash_sdcard_spi_read(); // get word
data[i*2+0] = (word>>8); // save byte
data[i*2+1] = (word>>0); // save byte
}
flash_sdcard_spi_read(); // read CRC (the CRC after the data block should clear the computed CRC)
if (SPI_CRC_RXR(FLASH_SDCARD_SPI)) { // CRC is wrong
token = 0xff;
} else { // no error occurred
token = 0;
}
// switch back to 8-bit SPI frames
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_TXE)); // wait until the end of any transmission
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy before disabling
spi_disable(SPI(FLASH_SDCARD_SPI)); // disable SPI to change format
spi_disable_crc(SPI(FLASH_SDCARD_SPI)); // disable CRC since we don't use it anymore (and this allows us to clear the CRC next time we use it)
spi_set_dff_8bit(SPI(FLASH_SDCARD_SPI)); // set SPI frame to 8 bits
spi_enable(SPI(FLASH_SDCARD_SPI)); // enable SPI back
} else { // start block token not received
token = 0xff;
}
return token;
}
static uint8_t flash_sdcard_write_block(uint8_t* data, size_t size)
{
if (size%2 || 0==size || NULL==data) { // can't (and shouldn't) read odd number of bytes
return 0xff;
}
spi_send(SPI(FLASH_SDCARD_SPI), 0xfe); // send start block token (see section 7.3.3.2)
// switch to 16-bits SPI data frame so we can use use built-in CRC-16
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_TXE)); // wait until the end of any transmission
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy before disabling
spi_disable(SPI(FLASH_SDCARD_SPI)); // disable SPI to change format
spi_set_dff_16bit(SPI(FLASH_SDCARD_SPI)); // set SPI frame to 16 bits
SPI_CRC_PR(FLASH_SDCARD_SPI) = 0x1021; // set CRC-16-CCITT polynomial for data blocks (x^16+x^12+x^5+1) (see section 7.2.3)
spi_enable_crc(SPI(FLASH_SDCARD_SPI)); // enable and clear CRC
spi_enable(SPI(FLASH_SDCARD_SPI)); // enable SPI back
// send block data (ideally use DMA, but switching makes it more complex and this part doesn't take too much time)
for (size_t i=0; i<size/2; i++) {
uint16_t word = (data[i*2+0]<<8)+data[i*2+1]; // prepare SPI frame
spi_send(SPI(FLASH_SDCARD_SPI), word); // senf data frame
}
spi_set_next_tx_from_crc(SPI(FLASH_SDCARD_SPI)); // send CRC
// switch back to 8-bit SPI frames
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_TXE)); // wait until the end of any transmission
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy before disabling
spi_disable(SPI(FLASH_SDCARD_SPI)); // disable SPI to change format
spi_set_next_tx_from_buffer(SPI(FLASH_SDCARD_SPI)); // don't send CRC
spi_disable_crc(SPI(FLASH_SDCARD_SPI)); // disable CRC since we don't use it anymore (and this allows us to clear the CRC next time we use it)
spi_set_dff_8bit(SPI(FLASH_SDCARD_SPI)); // set SPI frame to 8 bits
spi_enable(SPI(FLASH_SDCARD_SPI)); // enable SPI back
uint8_t token = 0xff;
while (0x01!=(token&0x11)) {
token = flash_sdcard_spi_read(); // get data response token (see section 7.3.3.1)
}
while (0==flash_sdcard_spi_read()); // wait N_EC while the card is busy programming the data
return token;
}
static uint16_t flash_sdcard_status(uint8_t* status)
{
// send CMD55 (APP_CMD) to issue following application command (see table 7-4)
uint8_t r1 = flash_sdcard_command_response(55, 0, NULL, 0); // (see table 7-3)
if ((r1&0xfe)) { // error occurred, not in idle state
return false;
}
// send ACMD13 command
gpio_clear(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS low to select slave and start SPI mode (see section 7.2)
flash_sdcard_spi_wait(); // wait for N_CS (min. 0, but it works better with 8 clock cycles) before writing command (see section 7.5.2.1)
flash_sdcard_send_command(13, 0); // send ACMD13 (SD_STATUS) (see table 7-4)
// get response token R2
uint16_t r2 = 0xffff; // response token R2 (see section 7.3.2.3)
for (uint8_t i=0; i<8 && r2&0x8000; i++) { // wait for N_CR (1 to 8 8 clock cycles) before reading response (see section 7.5.1.1)
r2 = (flash_sdcard_spi_read()<<8); // get first byte of response (see section 7.3.2.1)
}
if (0==(r2&0x8000)) { // got the first byte
r2 += flash_sdcard_spi_read(); // read second byte (see 7.3.2.3)
}
// get data block
if (0==r2) { // no error
if (flash_sdcard_read_block(status, 64)) { // read 512 bits data block containing SD status
r2 |= (1<<11); // set communication error
}
}
// end communication
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy (= transmission completed)
// wait for N_EC (min. 0) before closing communication (see section 7.5.1.1)
gpio_set(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS high to unselect card
// wait for N_DS (min. 0) before allowing any further communication (see section 7.5.1.1)
return r2;
}
static uint8_t flash_sdcard_data_read(uint8_t index, uint32_t argument, uint8_t* data, size_t size)
{
if (size%2 || 0==size || NULL==data) { // can't (and shouldn't) read odd number of bytes
return 0xff;
}
// send command token
gpio_clear(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS low to select slave and start SPI mode (see section 7.2)
flash_sdcard_spi_wait(); // wait for N_CS (min. 0, but it works better with 8 clock cycles) before writing command (see section 7.5.2.1)
flash_sdcard_send_command(index, argument); // send command token
// get response token R1
uint8_t r1 = 0xff; // response token R1 (see section 7.3.2.1)
for (uint8_t i=0; i<8 && r1&0x80; i++) { // wait for N_CR (1 to 8 8 clock cycles) before reading response (see section 7.5.1.1)
r1 = flash_sdcard_spi_read(); // get response (see section 7.3.2.1)
}
// get data block
if (0x00==r1) { // we can read a data block
if (flash_sdcard_read_block(data, size)) { // read data block
r1 |= (1<<3); // set communication error
}
}
// end communication
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy (= transmission completed)
// wait for N_EC (min. 0) before closing communication (see section 7.5.1.1)
gpio_set(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS high to unselect card
// wait for N_DS (min. 0) before allowing any further communication (see section 7.5.1.1)
return r1;
}
static uint8_t flash_sdcard_data_write(uint8_t index, uint32_t argument, uint8_t* data, size_t size)
{
if (size%2 || 0==size || NULL==data) { // can't (and shouldn't) write odd number of bytes
return 0xff;
}
// send command token
gpio_clear(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS low to select slave and start SPI mode (see section 7.2)
flash_sdcard_spi_wait(); // wait for N_CS (min. 0, but it works better with 8 clock cycles) before writing command (see section 7.5.2.1)
flash_sdcard_send_command(index, argument); // send command token
// get response token R1
uint8_t r1 = 0xff; // response token R1 (see section 7.3.2.1)
for (uint8_t i=0; i<8 && r1&0x80; i++) { // wait for N_CR (1 to 8 8 clock cycles) before reading response (see section 7.5.1.1)
r1 = flash_sdcard_spi_read(); // get response (see section 7.3.2.1)
}
// write data block
uint8_t drt = 0xff; // data response token (see section 7.3.3.1)
if (0x00==r1) { // we have to write the data block
drt = flash_sdcard_write_block(data, size); // write data block
}
// end communication
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy (= transmission completed)
// wait for N_EC (min. 0) before closing communication (see section 7.5.1.1)
gpio_set(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS high to unselect card
// wait for N_DS (min. 0) before allowing any further communication (see section 7.5.1.1)
return drt;
}
bool flash_sdcard_setup(void)
{
// reset values
initialized = false;
n_ac = 8;
sdcard_size = 0;
erase_size = 0;
// check if card is present
if (!flash_sdcard_card_detect()) {
return false;
}
// configure SPI peripheral
rcc_periph_clock_enable(RCC_SPI_SCK_PORT(FLASH_SDCARD_SPI)); // enable clock for GPIO peripheral for clock signal
gpio_set_mode(SPI_SCK_PORT(FLASH_SDCARD_SPI), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, SPI_SCK_PIN(FLASH_SDCARD_SPI)); // set SCK as output (clock speed will be negotiated later)
rcc_periph_clock_enable(RCC_SPI_MOSI_PORT(FLASH_SDCARD_SPI)); // enable clock for GPIO peripheral for MOSI signal
gpio_set_mode(SPI_MOSI_PORT(FLASH_SDCARD_SPI), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, SPI_MOSI_PIN(FLASH_SDCARD_SPI)); // set MOSI as output
rcc_periph_clock_enable(RCC_SPI_MISO_PORT(FLASH_SDCARD_SPI)); // enable clock for GPIO peripheral for MISO signal
gpio_set_mode(SPI_MISO_PORT(FLASH_SDCARD_SPI), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, SPI_MISO_PIN(FLASH_SDCARD_SPI)); // set MISO as input
gpio_set(SPI_MISO_PORT(FLASH_SDCARD_SPI), SPI_MISO_PIN(FLASH_SDCARD_SPI)); // pull pin high to detect when the card is not answering (or not present) since responses always start with MSb 0
rcc_periph_clock_enable(RCC_SPI_NSS_PORT(FLASH_SDCARD_SPI)); // enable clock for GPIO peripheral for NSS (CS) signal
gpio_set_mode(SPI_NSS_PORT(FLASH_SDCARD_SPI), GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set NSS (CS) as output
rcc_periph_clock_enable(RCC_AFIO); // enable clock for SPI alternate function
rcc_periph_clock_enable(RCC_SPI(FLASH_SDCARD_SPI)); // enable clock for SPI peripheral
spi_reset(SPI(FLASH_SDCARD_SPI)); // clear SPI values to default
spi_init_master(SPI(FLASH_SDCARD_SPI), SPI_CR1_BAUDRATE_FPCLK_DIV_256, SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE, SPI_CR1_CPHA_CLK_TRANSITION_1, SPI_CR1_DFF_8BIT, SPI_CR1_MSBFIRST); // initialise SPI as master, divide clock by 256 (72E6/256=281 kHz) since maximum SD card clock frequency (fOD, see section 7.8/6.6.6) during initial card-identification mode is 400 kHz (maximum SPI PCLK clock is 72 Mhz, depending on which SPI is used), set clock polarity to idle low (not that important), set clock phase to do bit change on falling edge (from SD card spec, polarity depends on clock phase), use 8 bits frames (as per spec), use MSb first
spi_set_full_duplex_mode(SPI(FLASH_SDCARD_SPI)); // ensure we are in full duplex mode
spi_enable_software_slave_management(SPI(FLASH_SDCARD_SPI)); // control NSS (CS) manually
spi_set_nss_high(SPI(FLASH_SDCARD_SPI)); // set NSS high (internally) so we can output
spi_disable_ss_output(SPI(FLASH_SDCARD_SPI)); // disable NSS output since we control CS manually
gpio_set(SPI_NSS_PORT(FLASH_SDCARD_SPI), SPI_NSS_PIN(FLASH_SDCARD_SPI)); // set CS high to unselect card
// sadly we can't use the interrupts as events to sleep (WFE) since sleep disables also communication (e.g. going to sleep until Rx buffer is not empty prevents transmission)
spi_enable(SPI(FLASH_SDCARD_SPI)); // enable SPI
// start card-identification (see section 7.2.1/4.2)
uint8_t r1 = 0;
// send CMD0 (GO_IDLE_START) to start the card identification (see section 7.2.1)
r1 = flash_sdcard_command_response(0, 0, NULL, 0); // (see table 7-3)
if (0x01!=r1) { // error occurred, not in idle state
return false;
}
// send CMD8 (SEND_IF_COND) to inform about voltage (1: 2.7-3.6V, aa: recommended check pattern) (see section 7.2.1)
uint8_t r7[4] = {0}; // to store response toke R7 (see section 7.3.2.6)
r1 = flash_sdcard_command_response(8, 0x000001aa, r7, sizeof(r7)); // (see table 7-3)
if (0x01==r1) { // command supported, in idle state
if (!(r7[2]&0x1)) { // 2.7-3.6V not supported (see table 5-1)
return false;
} else if (0xaa!=r7[3]) { // recommended pattern not returned (see section 4.3.13)
return false;
}
} else if (0x05!=r1) { // illegal command (cards < physical spec v2.0 don't support CMD8) (see section 7.2.1)
return false;
}
// send CMD58 (READ_OCR) to read Operation Conditions Register (see section 7.2.1)
uint8_t r3[4] = {0}; // to store response token R3 (see section 7.3.2.4)
r1 = flash_sdcard_command_response(58, 0, r3, sizeof(r3)); // (see table 7-3)
if (0x01!=r1) { // error occurred, not in idle state
return false;
} else if (!(r3[1]&0x30)) { // 3.3V not supported (see table 5-1)
return false;
}
do {
// send CMD55 (APP_CMD) to issue following application command (see table 7-4)
r1 = flash_sdcard_command_response(55, 0, NULL, 0); // (see table 7-3)
if (0x01!=r1) { // error occurred, not in idle state
return false;
}
// send ACMD41 (SD_SEND_OP_COND) with Host Capacity Support (0b: SDSC Only Host, 1b: SDHC or SDXC Supported) (see section 7.2.1)
r1 = flash_sdcard_command_response(41, 0x40000000, NULL, 0); // (see table 7-4)
if (r1&0xfe) { // error occurred
return false;
}
} while (0x00!=r1); // wait until card is ready (see section 7.2.1)
// send CMD58 (READ_OCR) to read Card Capacity Status (CCS) (see section 7.2.1)
r1 = flash_sdcard_command_response(58, 0, r3, sizeof(r3)); // (see table 7-3)
if (r1) { // error occurred
return false;
}
// card power up status bit (bit 31) is set when power up is complete (see table 5-1)
if (0x00==(r3[0]&0x80)) {
return false;
}
sdsc = (0==(r3[0]&0x40)); // CCS is bit 30 in OCR (see table 5-1)
// now the card identification is complete and we should be in data-transfer mode (see figure 7-1)
// we can switch clock frequency to fPP (max. 25 MHz) (see section 4.3/6.6.6)
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_TXE)); // wait until the end of any transmission
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy before disabling
spi_disable(SPI(FLASH_SDCARD_SPI)); // disable SPI to change clock speed
spi_set_baudrate_prescaler(SPI(FLASH_SDCARD_SPI), SPI_CR1_BR_FPCLK_DIV_4); // set clock speed to 18 MHz (72/4=18, < 25 MHz)
spi_enable(SPI(FLASH_SDCARD_SPI)); // enable SPI back
// send CMD9 (SEND_CSD) to get Card Specific Data (CSD) and calculate N_AC (see section 7.2.6)
uint8_t csd[16] = {0}; // CSD response (see chapter 7.2.6)
r1 = flash_sdcard_data_read(9, 0, csd, sizeof(csd)); // (see table 7-3)
if (r1) { // error occurred
return false;
}
// check if CSD structure version matches capacity (see section 5.3.1)
if ((sdsc && (csd[0]>>6)) || (!sdsc && 0==(csd[0]>>6))) {
return false;
}
// calculate N_AC value (we use our set minimum frequency 16 MHz to calculate time)
if (sdsc) { // calculate N_AC using TAAC and NSAC
static const float TAAC_UNITS[] = {1E-9, 10E-9, 100E-9, 1E-6, 10E-6, 100E-6, 1E-3, 10E-3}; // (see table 5-5)
static const float TAAC_VALUES[] = {10.0, 1.0, 1.2, 1.3, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 7.0, 8.0}; // (see table 5-5)
double taac = TAAC_VALUES[(csd[1]>>2)&0xf]*TAAC_UNITS[csd[1]&0x7]; // time in ns
n_ac=100*((taac*16E6)+(csd[2]*100))/8; // (see section 7.5.4)
} else { // value is fixed to 100 ms
n_ac=100E-3*16E6/8;
}
// calculate card size
if (sdsc) { // see section 5.3.2
uint16_t c_size = (((uint16_t)csd[6]&0x03)<<10)+((uint16_t)csd[7]<<2)+(csd[8]>>6);
uint8_t c_size_mutl = ((csd[9]&0x03)<<1)+((csd[10]&0x80)>>7);
uint8_t read_bl_len = (csd[5]&0x0f);
sdcard_size = ((c_size+1)*(1UL<<(c_size_mutl+2)))*(1UL<<read_bl_len);
} else { // see section 5.3.3
uint32_t c_size = ((uint32_t)(csd[7]&0x3f)<<16)+((uint16_t)csd[8]<<8)+csd[9];
sdcard_size = (c_size+1)*(512<<10);
}
// calculate erase size
if (sdsc) { // see section 5.3.2
erase_size = (((csd[10]&0x3f)<<1)+((csd[11]&0x80)>>7)+1)<<(((csd[12]&0x03)<<2)+(csd[13]>>6));
} else {
uint8_t status[64] = {0}; // SD status (see section 4.10.2)
uint16_t r2 = flash_sdcard_status(status); // get status (see table 7-4)
if (r2) { // error occurred
return false;
}
erase_size = (8192UL<<(status[10]>>4)); // calculate erase size (see table 4-44, section 4.10.2.4)
}
// ensure block length is 512 bytes for SDSC (should be per default) to we match SDHC/SDXC block size
if (sdsc) {
r1 = flash_sdcard_command_response(16, 512, NULL, 0); // set block size using CMD16 (SET_BLOCKLEN) (see table 7-3)
if (r1) { // error occurred
return false;
}
}
// try to switch to high speed mode (see section 7.2.14/4.3.10)
if (csd[4]&0x40) { // ensure CMD6 is supported by checking if command class 10 is set
uint32_t n_ac_back = n_ac; // backup N_AC
n_ac = 100E-3*16E6/8; // temporarily set timeout to 100 ms (see section 4.3.10.1)
// query access mode (group function 1) to check if high speed is supported (fPP=50MHz at 3.3V, we can be faster)
uint8_t fnc[64] = {0}; // function status response (see table 4-12)
r1 = flash_sdcard_data_read(6, 0x00fffff1, fnc, sizeof(fnc)); // check high speed function using CMD6 (SWITCH_FUNC) to check (mode 0) access mode (function group 1) (see table 7-3/4-30)
if (r1) { // error occurred
return false;
}
if (0x1==(fnc[16]&0x0f)) { // we can to access mode function 1 (see table 4-12)
r1 = flash_sdcard_data_read(6, 0x80fffff1, fnc, sizeof(fnc)); // switch to high speed function using CMD6 (SWITCH_FUNC) to switch (mode 1) access mode (function group 1) (see table 7-3/4-30)
if (r1) { // error occurred
return false;
}
if (0x1!=(fnc[16]&0x0f)) { // could not switch to high speed
return false;
}
// we can switch clock frequency to fPP (max. 50 MHz) (see section 6.6.7)
while (!(SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_TXE)); // wait until the end of any transmission
while (SPI_SR(SPI(FLASH_SDCARD_SPI))&SPI_SR_BSY); // wait until not busy before disabling
spi_disable(SPI(FLASH_SDCARD_SPI)); // disable SPI to change clock speed
spi_set_baudrate_prescaler(SPI(FLASH_SDCARD_SPI), SPI_CR1_BR_FPCLK_DIV_2); // set clock speed to 36 MHz (72/2=36 < 50 MHz)
spi_enable(SPI(FLASH_SDCARD_SPI)); // enable SPI back
n_ac_back /= 2; // since we go twice faster the N_AC timeout has to be halved
}
n_ac = n_ac_back; // restore N_AC
}
initialized = true;
return initialized;
}
uint64_t flash_sdcard_size(void)
{
return sdcard_size;
}
uint32_t flash_sdcard_erase_size(void)
{
return erase_size;
}
bool flash_sdcard_read_data(uint32_t block, uint8_t* data)
{
if (NULL==data) {
return false;
}
if (sdsc) { // the address for standard capacity cards must be provided in bytes
if (block>UINT32_MAX/512) { // check for integer overflow
return false;
} else {
block *= 512; // calculate byte address from block address
}
}
return (0==flash_sdcard_data_read(17, block, data, 512)); // read single data block using CMD17 (READ_SINGLE_BLOCK) (see table 7-3)
}
bool flash_sdcard_write_data(uint32_t block, uint8_t* data)
{
if (NULL==data) {
return false;
}
if (sdsc) { // the address for standard capacity cards must be provided in bytes
if (block>UINT32_MAX/512) { // check for integer overflow
return false;
} else {
block *= 512; // calculate byte address from block address
}
}
uint8_t drt = flash_sdcard_data_write(24, block, data, 512); // write single data block using CMD24 (WRITE_SINGLE_BLOCK) (see table 7-3)
if (0x05!=(drt&0x1f)) { // write block failed
return false;
}
// get status to check if programming succeeded
uint8_t r2[1] = {0}; // to store response token R2 (see section 7.3.2.3)
uint8_t r1 = flash_sdcard_command_response(13, 0, r2, sizeof(r2)); // get SD status using CMD13 (SEND_STATUS) (see table 7-3)
if (0x00!=r1) { // error occurred
return false;
} else if (r2[0]) { // programming error
return false;
}
return true; // programming succeeded
}
SPI_MOSI_PORT
#define SPI_MOSI_PORT(x)
get SPI port for MOSI signal based on SPI identifier
Definition: global.h:297
flash_sdcard_write_block
static uint8_t flash_sdcard_write_block(uint8_t *data, size_t size)
write a data block
Definition: flash_sdcard.c:222
flash_sdcard.h
library to communicate with an SD card flash memory using the SPI mode (API)
flash_sdcard_card_detect
static bool flash_sdcard_card_detect(void)
test if card is present
Definition: flash_sdcard.c:106
flash_sdcard_data_write
static uint8_t flash_sdcard_data_write(uint8_t index, uint32_t argument, uint8_t *data, size_t size)
transmit command token, receive response token and write data block
Definition: flash_sdcard.c:349
SPI_NSS_PORT
#define SPI_NSS_PORT(x)
get SPI port for NSS signal based on SPI identifier
Definition: global.h:291
SPI_CRC_PR
#define SPI_CRC_PR(x)
get SPI CRC polynomial register based on SPI identifier
Definition: global.h:307
SPI_MOSI_PIN
#define SPI_MOSI_PIN(x)
get SPI pin for MOSI signal based on SPI identifier
Definition: global.h:305
initialized
static bool initialized
if the card has been initialized successfully
Definition: flash_sdcard.c:45
sdsc
static bool sdsc
is it a Standard Capacity SD card (true), or High Capacity SD cards (false)
Definition: flash_sdcard.c:54
global.h
global definitions and methods (API)
SPI_CRC_RXR
#define SPI_CRC_RXR(x)
get SPI CRC receive register based on SPI identifier
Definition: global.h:311
flash_sdcard_status
static uint16_t flash_sdcard_status(uint8_t *status)
get card status
Definition: flash_sdcard.c:265
RCC_SPI_MISO_PORT
#define RCC_SPI_MISO_PORT(x)
get RCC for GPIO port for SPI MISO signals
Definition: global.h:281
n_ac
static uint32_t n_ac
maximum N_AC value (in 8-clock cycles) (time between the response token R1 and data block when readin...
Definition: flash_sdcard.c:49
RCC_SPI_MOSI_PORT
#define RCC_SPI_MOSI_PORT(x)
get RCC for GPIO port for SPI MOSI signals
Definition: global.h:286
RCC_SPI
#define RCC_SPI(x)
get RCC for SPI based on SPI identifier
Definition: global.h:269
flash_sdcard_size
uint64_t flash_sdcard_size(void)
get size of SD card flash memory
Definition: flash_sdcard.c:557
SPI_NSS_PIN
#define SPI_NSS_PIN(x)
get SPI pin for NSS signal based on SPI identifier
Definition: global.h:299
SPI_SCK_PORT
#define SPI_SCK_PORT(x)
get SPI port for SCK signal based on SPI identifier
Definition: global.h:293
flash_sdcard_spi_read
static uint16_t flash_sdcard_spi_read(void)
read one SPI word
Definition: flash_sdcard.c:93
flash_sdcard_read_block
static uint8_t flash_sdcard_read_block(uint8_t *data, size_t size)
read a data block
Definition: flash_sdcard.c:168
flash_sdcard_spi_wait
static void flash_sdcard_spi_wait(void)
wait one SPI round (one SPI word)
Definition: flash_sdcard.c:85
SPI_MISO_PORT
#define SPI_MISO_PORT(x)
get SPI port for MISO signal based on SPI identifier
Definition: global.h:295
SPI
#define SPI(x)
get SPI based on SPI identifier
Definition: global.h:267
flash_sdcard_data_read
static uint8_t flash_sdcard_data_read(uint8_t index, uint32_t argument, uint8_t *data, size_t size)
transmit command token, receive response token and data block
Definition: flash_sdcard.c:309
RCC_SPI_SCK_PORT
#define RCC_SPI_SCK_PORT(x)
get RCC for GPIO port for SPI SCK signals
Definition: global.h:276
flash_sdcard_read_data
bool flash_sdcard_read_data(uint32_t block, uint8_t *data)
read data on flash of SD card
Definition: flash_sdcard.c:567
LENGTH
#define LENGTH(x)
get the length of an array
Definition: global.h:26
flash_sdcard_command_response
static uint8_t flash_sdcard_command_response(uint8_t index, uint32_t argument, uint8_t *response, size_t size)
transmit command token and receive response token
Definition: flash_sdcard.c:137
flash_sdcard_setup
bool flash_sdcard_setup(void)
setup communication with SD card
Definition: flash_sdcard.c:381
sdcard_size
static uint64_t sdcard_size
size of card in bytes
Definition: flash_sdcard.c:56
SPI_MISO_PIN
#define SPI_MISO_PIN(x)
get SPI pin for MISO signal based on SPI identifier
Definition: global.h:303
flash_sdcard_write_data
bool flash_sdcard_write_data(uint32_t block, uint8_t *data)
write data on flash of SD card
Definition: flash_sdcard.c:582
erase_size
static uint32_t erase_size
size of an erase block bytes
Definition: flash_sdcard.c:58
RCC_SPI_NSS_PORT
#define RCC_SPI_NSS_PORT(x)
get RCC for GPIO port for SPI NSS signals
Definition: global.h:271
flash_sdcard_send_command
static void flash_sdcard_send_command(uint8_t index, uint32_t argument)
transmit command token
Definition: flash_sdcard.c:118
FLASH_SDCARD_SPI
#define FLASH_SDCARD_SPI
SPI peripheral.
Definition: flash_sdcard.c:41
SPI_SCK_PIN
#define SPI_SCK_PIN(x)
get SPI pin for SCK signal based on SPI identifier
Definition: global.h:301
flash_sdcard_erase_size
uint32_t flash_sdcard_erase_size(void)
get size of a erase block
Definition: flash_sdcard.c:562
crc7_table
static const uint8_t crc7_table[]
table for CRC-7 calculation for the command messages (see section 4.5)
Definition: flash_sdcard.c:64