USBMSD SD card Hello World for Mbed platforms
Dependencies: mbed USBMSD_SD USBDevice
Diff: ChaNFSSD/SDFileSystem.cpp
- Revision:
- 14:757226626acb
- Parent:
- 13:32b8a767cf0e
- Child:
- 16:c753717bfd4d
--- a/ChaNFSSD/SDFileSystem.cpp Mon Dec 05 14:34:29 2011 +0000 +++ b/ChaNFSSD/SDFileSystem.cpp Tue Dec 06 12:07:12 2011 +0000 @@ -24,20 +24,20 @@ * ------------ * SD and MMC cards support a number of interfaces, but common to them all * is one based on SPI. This is the one I'm implmenting because it means - * it is much more portable even though not so performant, and we already + * it is much more portable even though not so performant, and we already * have the mbed SPI Interface! * - * The main reference I'm using is Chapter 7, "SPI Mode" of: + * The main reference I'm using is Chapter 7, "SPI Mode" of: * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf * * SPI Startup * ----------- * The SD card powers up in SD mode. The SPI interface mode is selected by - * asserting CS low and sending the reset command (CMD0). The card will + * asserting CS low and sending the reset command (CMD0). The card will * respond with a (R1) response. * - * CMD8 is optionally sent to determine the voltage range supported, and - * indirectly determine whether it is a version 1.x SD/non-SD card or + * CMD8 is optionally sent to determine the voltage range supported, and + * indirectly determine whether it is a version 1.x SD/non-SD card or * version 2.x. I'll just ignore this for now. * * ACMD41 is repeatedly issued to initialise the card, until "in idle" @@ -51,21 +51,21 @@ * The SD SPI protocol is based on transactions made up of 8-bit words, with * the host starting every bus transaction by asserting the CS signal low. The * card always responds to commands, data blocks and errors. - * - * The protocol supports a CRC, but by default it is off (except for the + * + * The protocol supports a CRC, but by default it is off (except for the * first reset CMD0, where the CRC can just be pre-calculated, and CMD8) - * I'll leave the CRC off I think! - * - * Standard capacity cards have variable data block sizes, whereas High + * I'll leave the CRC off I think! + * + * Standard capacity cards have variable data block sizes, whereas High * Capacity cards fix the size of data block to 512 bytes. I'll therefore * just always use the Standard Capacity cards with a block size of 512 bytes. * This is set with CMD16. * - * You can read and write single blocks (CMD17, CMD25) or multiple blocks + * You can read and write single blocks (CMD17, CMD25) or multiple blocks * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When - * the card gets a read command, it responds with a response token, and then + * the card gets a read command, it responds with a response token, and then * a data token or an error. - * + * * SPI Command Format * ------------------ * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC. @@ -81,7 +81,7 @@ * SPI Response Format * ------------------- * The main response format (R1) is a status byte (normally zero). Key flags: - * idle - 1 if the card is in an idle state/initialising + * idle - 1 if the card is in an idle state/initialising * cmd - 1 if an illegal command code was detected * * +-------------------------------------------------+ @@ -93,7 +93,7 @@ * * Data Response Token * ------------------- - * Every data block written to the card is acknowledged by a byte + * Every data block written to the card is acknowledged by a byte * response token * * +----------------------+ @@ -108,19 +108,20 @@ * * Block transfers have a byte header, followed by the data, followed * by a 16-bit CRC. In our case, the data will always be 512 bytes. - * + * * +------+---------+---------+- - - -+---------+-----------+----------+ - * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] | + * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] | * +------+---------+---------+- - - -+---------+-----------+----------+ */ - + #include "SDFileSystem.h" #define SD_COMMAND_TIMEOUT 5000 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) : - FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) { - _cs = 1; + FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) { + _status = 0; + _cs = 1; } #define R1_IDLE_STATE (1 << 0) @@ -144,23 +145,23 @@ int SDFileSystem::initialise_card() { // Set to 100kHz for initialisation, and clock card with cs = 1 - _spi.frequency(100000); + _spi.frequency(100000); _cs = 1; - for(int i=0; i<16; i++) { + for (int i=0; i<16; i++) { _spi.write(0xFF); } // send CMD0, should return with all zeros except IDLE STATE set (bit 0) - if(_cmd(0, 0) != R1_IDLE_STATE) { + if (_cmd(0, 0) != R1_IDLE_STATE) { fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n"); return SDCARD_FAIL; } // send CMD8 to determine whther it is ver 2.x int r = _cmd8(); - if(r == R1_IDLE_STATE) { + if (r == R1_IDLE_STATE) { return initialise_card_v2(); - } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) { + } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) { return initialise_card_v1(); } else { fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n"); @@ -169,9 +170,9 @@ } int SDFileSystem::initialise_card_v1() { - for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { - _cmd(55, 0); - if(_cmd(41, 0) == 0) { + for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { + _cmd(55, 0); + if (_cmd(41, 0) == 0) { return SDCARD_V1; } } @@ -181,10 +182,10 @@ } int SDFileSystem::initialise_card_v2() { - - for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { - _cmd(55, 0); - if(_cmd(41, 0) == 0) { + + for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { + _cmd(55, 0); + if (_cmd(41, 0) == 0) { _cmd58(); return SDCARD_V2; } @@ -203,45 +204,51 @@ _sectors = _sd_sectors(); // Set block length to 512 (CMD16) - if(_cmd(16, 512) != 0) { + if (_cmd(16, 512) != 0) { fprintf(stderr, "Set 512-byte block timed out\n"); return 1; } - + _spi.frequency(5000000); // Set to 5MHz for data transfer - return 0; + return _status; } int SDFileSystem::disk_write(const char *buffer, int block_number) { // set write address for single block (CMD24) - if(_cmd(24, block_number * 512) != 0) { + if (_cmd(24, block_number * 512) != 0) { return 1; } // send the data block - _write(buffer, 512); - return 0; + _write(buffer, 512); + return 0; } -int SDFileSystem::disk_read(char *buffer, int block_number) { +int SDFileSystem::disk_read(char *buffer, int block_number) { // set read address for single block (CMD17) - if(_cmd(17, block_number * 512) != 0) { + if (_cmd(17, block_number * 512) != 0) { return 1; } - + // receive the data _read(buffer, 512); return 0; } -int SDFileSystem::disk_status() { return 0; } -int SDFileSystem::disk_sync() { return 0; } -int SDFileSystem::disk_sectors() { return _sectors; } +int SDFileSystem::disk_status() { + return _status; +} +int SDFileSystem::disk_sync() { + return 0; +} +int SDFileSystem::disk_sectors() { + return _sectors; +} // PRIVATE FUNCTIONS int SDFileSystem::_cmd(int cmd, int arg) { - _cs = 0; + _cs = 0; // send a command _spi.write(0x40 | cmd); @@ -252,9 +259,9 @@ _spi.write(0x95); // wait for the repsonse (response[7] == 0) - for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { + for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { int response = _spi.write(0xFF); - if(!(response & 0x80)) { + if (!(response & 0x80)) { _cs = 1; _spi.write(0xFF); return response; @@ -265,7 +272,7 @@ return -1; // timeout } int SDFileSystem::_cmdx(int cmd, int arg) { - _cs = 0; + _cs = 0; // send a command _spi.write(0x40 | cmd); @@ -276,9 +283,9 @@ _spi.write(0x95); // wait for the repsonse (response[7] == 0) - for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { + for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { int response = _spi.write(0xFF); - if(!(response & 0x80)) { + if (!(response & 0x80)) { return response; } } @@ -289,9 +296,9 @@ int SDFileSystem::_cmd58() { - _cs = 0; + _cs = 0; int arg = 0; - + // send a command _spi.write(0x40 | 58); _spi.write(arg >> 24); @@ -301,9 +308,9 @@ _spi.write(0x95); // wait for the repsonse (response[7] == 0) - for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { + for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { int response = _spi.write(0xFF); - if(!(response & 0x80)) { + if (!(response & 0x80)) { int ocr = _spi.write(0xFF) << 24; ocr |= _spi.write(0xFF) << 16; ocr |= _spi.write(0xFF) << 8; @@ -320,8 +327,8 @@ } int SDFileSystem::_cmd8() { - _cs = 0; - + _cs = 0; + // send a command _spi.write(0x40 | 8); // CMD8 _spi.write(0x00); // reserved @@ -331,16 +338,16 @@ _spi.write(0x87); // crc // wait for the repsonse (response[7] == 0) - for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) { + for (int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) { char response[5]; response[0] = _spi.write(0xFF); - if(!(response[0] & 0x80)) { - for(int j=1; j<5; j++) { - response[i] = _spi.write(0xFF); - } - _cs = 1; - _spi.write(0xFF); - return response[0]; + if (!(response[0] & 0x80)) { + for (int j=1; j<5; j++) { + response[i] = _spi.write(0xFF); + } + _cs = 1; + _spi.write(0xFF); + return response[0]; } } _cs = 1; @@ -352,54 +359,54 @@ _cs = 0; // read until start byte (0xFF) - while(_spi.write(0xFF) != 0xFE); + while (_spi.write(0xFF) != 0xFE); // read data - for(int i=0; i<length; i++) { + for (int i=0; i<length; i++) { buffer[i] = _spi.write(0xFF); } _spi.write(0xFF); // checksum _spi.write(0xFF); - _cs = 1; + _cs = 1; _spi.write(0xFF); return 0; } int SDFileSystem::_write(const char *buffer, int length) { _cs = 0; - + // indicate start of block _spi.write(0xFE); - + // write the data - for(int i=0; i<length; i++) { + for (int i=0; i<length; i++) { _spi.write(buffer[i]); } - + // write the checksum - _spi.write(0xFF); + _spi.write(0xFF); _spi.write(0xFF); // check the repsonse token - if((_spi.write(0xFF) & 0x1F) != 0x05) { + if ((_spi.write(0xFF) & 0x1F) != 0x05) { _cs = 1; - _spi.write(0xFF); + _spi.write(0xFF); return 1; } // wait for write to finish - while(_spi.write(0xFF) == 0); + while (_spi.write(0xFF) == 0); - _cs = 1; + _cs = 1; _spi.write(0xFF); return 0; } static int ext_bits(char *data, int msb, int lsb) { int bits = 0; - int size = 1 + msb - lsb; - for(int i=0; i<size; i++) { + int size = 1 + msb - lsb; + for (int i=0; i<size; i++) { int position = lsb + i; int byte = 15 - (position >> 3); int bit = position & 0x7; @@ -412,13 +419,13 @@ int SDFileSystem::_sd_sectors() { // CMD9, Response R2 (R1 byte + 16-byte block read) - if(_cmdx(9, 0) != 0) { + if (_cmdx(9, 0) != 0) { fprintf(stderr, "Didn't get a response from the disk\n"); return 0; } - - char csd[16]; - if(_read(csd, 16) != 0) { + + char csd[16]; + if (_read(csd, 16) != 0) { fprintf(stderr, "Couldn't read csd response from disk\n"); return 0; } @@ -434,8 +441,8 @@ int read_bl_len = ext_bits(csd, 83, 80); // printf("CSD_STRUCT = %d\n", csd_structure); - - if(csd_structure != 0) { + + if (csd_structure != 0) { fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n"); return 0; } @@ -444,7 +451,7 @@ // where // BLOCKNR = (C_SIZE+1) * MULT // MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8) - // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12) + // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12) int block_len = 1 << read_bl_len; int mult = 1 << (c_size_mult + 2); @@ -452,7 +459,7 @@ capacity = blocknr * block_len; int blocks = capacity / 512; - + return blocks; } @@ -460,3 +467,10 @@ int SDFileSystem::disk_size() { return capacity; } + +void SDFileSystem::suspendStateChanged(unsigned int suspended) { + printf("st: %d\r\n", suspended); + _status = (suspended) ? 0 : 0x04; +} + +