Klaus Bu
/
SDHCFileSystem
SDHC support till 32GB
SDHCFileSystem.cpp
- Committer:
- xxll
- Date:
- 2010-07-24
- Revision:
- 0:90601632692f
File content as of revision 0:90601632692f:
/* mbed SDFileSystem Library, for providing file access to 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. */ /* Introduction * ------------ * 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 * have the mbed SPI Interface! * * 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 * 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 * version 2.x. I'll just ignore this for now. * * ACMD41 is repeatedly issued to initialise the card, until "in idle" * (bit 0) of the R1 response goes to '0', indicating it is initialised. * * You should also indicate whether the host supports High Capicity cards, * and check whether the card is high capacity - i'll also ignore this * * SPI Protocol * ------------ * 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 * 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 * 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 * (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 * a data token or an error. * * SPI Command Format * ------------------ * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC. * * +---------------+------------+------------+-----------+----------+--------------+ * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 | * +---------------+------------+------------+-----------+----------+--------------+ * * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95) * * All Application Specific commands shall be preceded with APP_CMD (CMD55). * * 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 * cmd - 1 if an illegal command code was detected * * +-------------------------------------------------+ * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle | * +-------------------------------------------------+ * * R1b is the same, except it is followed by a busy signal (zeros) until * the first non-zero byte when it is ready again. * * Data Response Token * ------------------- * Every data block written to the card is acknowledged by a byte * response token * * +----------------------+ * | xxx | 0 | status | 1 | * +----------------------+ * 010 - OK! * 101 - CRC Error * 110 - Write Error * * Single Block Read and Write * --------------------------- * * 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] | * +------+---------+---------+- - - -+---------+-----------+----------+ */ /* * Comment: Changes for SDHC support till 32GB * Name: KB * Date: 07/24/2010 * Release: 0.1 */ #include "SDHCFileSystem.h" #define DEBUG #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; } #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 SDFileSystem::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 SDFileSystem::initialise_card_v1() { for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { _cmd(55, 0); if(_cmd(41, 0) == 0) { cdv = 512; #ifdef DEBUG printf("\n\rInit: SEDCARD_V1\n\r"); #endif return SDCARD_V1; } } fprintf(stderr, "Timeout waiting for v1.x card\n"); return SDCARD_FAIL; } int SDFileSystem::initialise_card_v2() { for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { wait_ms(50); _cmd58(); _cmd(55, 0); if(_cmd(41, 0x40000000) == 0) { _cmd58(); #ifdef DEBUG printf("\n\rInit: SDCARD_V2\n\r"); #endif cdv = 1; return SDCARD_V2; } } fprintf(stderr, "Timeout waiting for v2.x card\n"); return SDCARD_FAIL; } int SDFileSystem::disk_initialize() { int i = initialise_card(); #ifdef DEBUG printf("init card = %d\n", i); #endif _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 SDFileSystem::disk_write(const char *buffer, int block_number) { // set write address for single block (CMD24) if(_cmd(24, block_number * cdv) != 0) { return 1; } // send the data block _write(buffer, 512); return 0; } int SDFileSystem::disk_read(char *buffer, int block_number) { // set read address for single block (CMD17) if(_cmd(17, block_number * cdv) != 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; } // PRIVATE FUNCTIONS int SDFileSystem::_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 SDFileSystem::_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 SDFileSystem::_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 SDFileSystem::_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 SDFileSystem::_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 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++) { _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 SDFileSystem::_sd_sectors() { int c_size, c_size_mult, read_bl_len; int block_len, mult, blocknr, capacity; int blocks, hc_c_size; uint64_t hc_capacity; // 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); #ifdef DEBUG printf("\n\rCSD_STRUCT = %d\n", csd_structure); #endif switch (csd_structure){ case 0: cdv = 512; c_size = ext_bits(csd, 73, 62); c_size_mult = ext_bits(csd, 49, 47); read_bl_len = ext_bits(csd, 83, 80); block_len = 1 << read_bl_len; mult = 1 << (c_size_mult + 2); blocknr = (c_size + 1) * mult; capacity = blocknr * block_len; blocks = capacity / 512; #ifdef DEBUG printf("\n\rSDCard\n\rc_size: %.4X \n\rcapacity: %.ld \n\rsectors: %d\n\r", c_size, capacity, blocks); #endif break; case 1: cdv = 1; hc_c_size = ext_bits(csd, 63, 48); int hc_read_bl_len = ext_bits(csd, 83, 80); hc_capacity = hc_c_size+1; blocks = (hc_c_size+1)*1024; #ifdef DEBUG printf("\n\rSDHC Card \n\rhc_c_size: %.4X \n\rcapacity: %.lld \n\rsectors: %d\n\r", hc_c_size, hc_capacity*512*1024, blocks); #endif break; default: fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n"); return 0; break; }; return blocks; }