USBMSD SD card Hello World for Mbed platforms
Dependencies: mbed USBMSD_SD USBDevice
USBDevice/USBMSD/USB_SDcard.cpp
- Committer:
- samux
- Date:
- 2011-11-12
- Revision:
- 4:980e6470dcce
- Child:
- 6:126c4d980196
File content as of revision 4:980e6470dcce:
/* mbed USB_SDcard Library, for accessing SD cards * Copyright (c) 2008-2010, sford * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "USB_SDcard.h" #define SD_COMMAND_TIMEOUT 5000 USB_SDcard::USB_SDcard(PinName mosi, PinName miso, PinName sclk, PinName cs): _spi(mosi, miso, sclk), _cs(cs) { _cs = 1; init(); } #define R1_IDLE_STATE (1 << 0) #define R1_ERASE_RESET (1 << 1) #define R1_ILLEGAL_COMMAND (1 << 2) #define R1_COM_CRC_ERROR (1 << 3) #define R1_ERASE_SEQUENCE_ERROR (1 << 4) #define R1_ADDRESS_ERROR (1 << 5) #define R1_PARAMETER_ERROR (1 << 6) // Types // - v1.x Standard Capacity // - v2.x Standard Capacity // - v2.x High Capacity // - Not recognised as an SD Card #define SDCARD_FAIL 0 #define SDCARD_V1 1 #define SDCARD_V2 2 #define SDCARD_V2HC 3 int USB_SDcard::initialise_card() { // Set to 100kHz for initialisation, and clock card with cs = 1 _spi.frequency(100000); _cs = 1; 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) { 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) { return initialise_card_v2(); } 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"); return SDCARD_FAIL; } } int USB_SDcard::initialise_card_v1() { for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { _cmd(55, 0); if(_cmd(41, 0) == 0) { return SDCARD_V1; } } fprintf(stderr, "Timeout waiting for v1.x card\n"); return SDCARD_FAIL; } int USB_SDcard::initialise_card_v2() { for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { _cmd(55, 0); if(_cmd(41, 0) == 0) { _cmd58(); return SDCARD_V2; } } fprintf(stderr, "Timeout waiting for v2.x card\n"); return SDCARD_FAIL; } int USB_SDcard::init() { int i = initialise_card(); // printf("init card = %d\n", i); // printf("OK\n"); _sectors = _sd_sectors(); // Set block length to 512 (CMD16) if(_cmd(16, 512) != 0) { fprintf(stderr, "Set 512-byte block timed out\n"); return 1; } _spi.frequency(1000000); // Set to 1MHz for data transfer return 0; } int USB_SDcard::blockWrite(uint8_t * buffer, uint16_t block_number) { // set write address for single block (CMD24) if(_cmd(24, block_number * 512) != 0) { return 1; } // send the data block _write((const char *)buffer, 512); return 0; } int USB_SDcard::blockRead(uint8_t * buffer, uint16_t block_number) { // set read address for single block (CMD17) if(_cmd(17, block_number * 512) != 0) { return 1; } // receive the data _read((char *)buffer, 512); return 0; } int USB_SDcard::disk_status() { return 0; } int USB_SDcard::disk_sync() { return 0; } int USB_SDcard::disk_sectors() { return _sectors; } // PRIVATE FUNCTIONS int USB_SDcard::_cmd(int cmd, int arg) { _cs = 0; // send a command _spi.write(0x40 | cmd); _spi.write(arg >> 24); _spi.write(arg >> 16); _spi.write(arg >> 8); _spi.write(arg >> 0); _spi.write(0x95); // wait for the repsonse (response[7] == 0) for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { int response = _spi.write(0xFF); if(!(response & 0x80)) { _cs = 1; _spi.write(0xFF); return response; } } _cs = 1; _spi.write(0xFF); return -1; // timeout } int USB_SDcard::_cmdx(int cmd, int arg) { _cs = 0; // send a command _spi.write(0x40 | cmd); _spi.write(arg >> 24); _spi.write(arg >> 16); _spi.write(arg >> 8); _spi.write(arg >> 0); _spi.write(0x95); // wait for the repsonse (response[7] == 0) for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { int response = _spi.write(0xFF); if(!(response & 0x80)) { return response; } } _cs = 1; _spi.write(0xFF); return -1; // timeout } int USB_SDcard::_cmd58() { _cs = 0; int arg = 0; // send a command _spi.write(0x40 | 58); _spi.write(arg >> 24); _spi.write(arg >> 16); _spi.write(arg >> 8); _spi.write(arg >> 0); _spi.write(0x95); // wait for the repsonse (response[7] == 0) for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { int response = _spi.write(0xFF); if(!(response & 0x80)) { int ocr = _spi.write(0xFF) << 24; ocr |= _spi.write(0xFF) << 16; ocr |= _spi.write(0xFF) << 8; ocr |= _spi.write(0xFF) << 0; // printf("OCR = 0x%08X\n", ocr); _cs = 1; _spi.write(0xFF); return response; } } _cs = 1; _spi.write(0xFF); return -1; // timeout } int USB_SDcard::_cmd8() { _cs = 0; // send a command _spi.write(0x40 | 8); // CMD8 _spi.write(0x00); // reserved _spi.write(0x00); // reserved _spi.write(0x01); // 3.3v _spi.write(0xAA); // check pattern _spi.write(0x87); // crc // wait for the repsonse (response[7] == 0) 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]; } } _cs = 1; _spi.write(0xFF); return -1; // timeout } int USB_SDcard::_read(char *buffer, int length) { _cs = 0; // read until start byte (0xFF) while(_spi.write(0xFF) != 0xFE); // read data for(int i=0; i<length; i++) { buffer[i] = _spi.write(0xFF); } _spi.write(0xFF); // checksum _spi.write(0xFF); _cs = 1; _spi.write(0xFF); return 0; } int USB_SDcard::_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++) { _spi.write(buffer[i]); } // write the checksum _spi.write(0xFF); _spi.write(0xFF); // check the repsonse token if((_spi.write(0xFF) & 0x1F) != 0x05) { _cs = 1; _spi.write(0xFF); return 1; } // wait for write to finish while(_spi.write(0xFF) == 0); _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 position = lsb + i; int byte = 15 - (position >> 3); int bit = position & 0x7; int value = (data[byte] >> bit) & 1; bits |= value << i; } return bits; } int USB_SDcard::_sd_sectors() { // CMD9, Response R2 (R1 byte + 16-byte block read) 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) { fprintf(stderr, "Couldn't read csd response from disk\n"); return 0; } // csd_structure : csd[127:126] // c_size : csd[73:62] // c_size_mult : csd[49:47] // read_bl_len : csd[83:80] - the *maximum* read block length int csd_structure = ext_bits(csd, 127, 126); int c_size = ext_bits(csd, 73, 62); int c_size_mult = ext_bits(csd, 49, 47); int read_bl_len = ext_bits(csd, 83, 80); // printf("CSD_STRUCT = %d\n", csd_structure); if(csd_structure != 0) { fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n"); return 0; } // memory capacity = BLOCKNR * BLOCK_LEN // 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) int block_len = 1 << read_bl_len; int mult = 1 << (c_size_mult + 2); int blocknr = (c_size + 1) * mult; int capacity = blocknr * block_len; int blocks = capacity / 512; return blocks; }