Pranav Sawant / SDFileSystem

Oct122012mbedLab

Dependents:   Lab3_VoiceMeter

Fork of SDFileSystem by Junichi Katsu

SDFileSystem.cpp@2:baca12fae67e, 2012-10-12 (annotated)

Committer:
psawant9
Date:
Fri Oct 12 16:02:17 2012 +0000
Revision:
2:baca12fae67e
Parent:
0:b1ddfc9a9b25 
Done

Who changed what in which revision?

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psawant9 2:baca12fae67e 1 /* mbed SDFileSystem Library, for providing file access to SD cards
psawant9 2:baca12fae67e 2 * Copyright (c) 2008-2010, sford
psawant9 2:baca12fae67e 3 *
psawant9 2:baca12fae67e 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
psawant9 2:baca12fae67e 5 * of this software and associated documentation files (the "Software"), to deal
psawant9 2:baca12fae67e 6 * in the Software without restriction, including without limitation the rights
psawant9 2:baca12fae67e 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
psawant9 2:baca12fae67e 8 * copies of the Software, and to permit persons to whom the Software is
psawant9 2:baca12fae67e 9 * furnished to do so, subject to the following conditions:
psawant9 2:baca12fae67e 10 *
psawant9 2:baca12fae67e 11 * The above copyright notice and this permission notice shall be included in
psawant9 2:baca12fae67e 12 * all copies or substantial portions of the Software.
psawant9 2:baca12fae67e 13 *
psawant9 2:baca12fae67e 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
psawant9 2:baca12fae67e 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
psawant9 2:baca12fae67e 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
psawant9 2:baca12fae67e 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
psawant9 2:baca12fae67e 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
psawant9 2:baca12fae67e 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
psawant9 2:baca12fae67e 20 * THE SOFTWARE.
psawant9 2:baca12fae67e 21 */
psawant9 2:baca12fae67e 22
psawant9 2:baca12fae67e 23 /* Introduction
psawant9 2:baca12fae67e 24 * ------------
psawant9 2:baca12fae67e 25 * SD and MMC cards support a number of interfaces, but common to them all
psawant9 2:baca12fae67e 26 * is one based on SPI. This is the one I'm implmenting because it means
psawant9 2:baca12fae67e 27 * it is much more portable even though not so performant, and we already
psawant9 2:baca12fae67e 28 * have the mbed SPI Interface!
psawant9 2:baca12fae67e 29 *
psawant9 2:baca12fae67e 30 * The main reference I'm using is Chapter 7, "SPI Mode" of:
psawant9 2:baca12fae67e 31 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
psawant9 2:baca12fae67e 32 *
psawant9 2:baca12fae67e 33 * SPI Startup
psawant9 2:baca12fae67e 34 * -----------
psawant9 2:baca12fae67e 35 * The SD card powers up in SD mode. The SPI interface mode is selected by
psawant9 2:baca12fae67e 36 * asserting CS low and sending the reset command (CMD0). The card will
psawant9 2:baca12fae67e 37 * respond with a (R1) response.
psawant9 2:baca12fae67e 38 *
psawant9 2:baca12fae67e 39 * CMD8 is optionally sent to determine the voltage range supported, and
psawant9 2:baca12fae67e 40 * indirectly determine whether it is a version 1.x SD/non-SD card or
psawant9 2:baca12fae67e 41 * version 2.x. I'll just ignore this for now.
psawant9 2:baca12fae67e 42 *
psawant9 2:baca12fae67e 43 * ACMD41 is repeatedly issued to initialise the card, until "in idle"
psawant9 2:baca12fae67e 44 * (bit 0) of the R1 response goes to '0', indicating it is initialised.
psawant9 2:baca12fae67e 45 *
psawant9 2:baca12fae67e 46 * You should also indicate whether the host supports High Capicity cards,
psawant9 2:baca12fae67e 47 * and check whether the card is high capacity - i'll also ignore this
psawant9 2:baca12fae67e 48 *
psawant9 2:baca12fae67e 49 * SPI Protocol
psawant9 2:baca12fae67e 50 * ------------
psawant9 2:baca12fae67e 51 * The SD SPI protocol is based on transactions made up of 8-bit words, with
psawant9 2:baca12fae67e 52 * the host starting every bus transaction by asserting the CS signal low. The
psawant9 2:baca12fae67e 53 * card always responds to commands, data blocks and errors.
psawant9 2:baca12fae67e 54 *
psawant9 2:baca12fae67e 55 * The protocol supports a CRC, but by default it is off (except for the
psawant9 2:baca12fae67e 56 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
psawant9 2:baca12fae67e 57 * I'll leave the CRC off I think!
psawant9 2:baca12fae67e 58 *
psawant9 2:baca12fae67e 59 * Standard capacity cards have variable data block sizes, whereas High
psawant9 2:baca12fae67e 60 * Capacity cards fix the size of data block to 512 bytes. I'll therefore
psawant9 2:baca12fae67e 61 * just always use the Standard Capacity cards with a block size of 512 bytes.
psawant9 2:baca12fae67e 62 * This is set with CMD16.
psawant9 2:baca12fae67e 63 *
psawant9 2:baca12fae67e 64 * You can read and write single blocks (CMD17, CMD25) or multiple blocks
psawant9 2:baca12fae67e 65 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
psawant9 2:baca12fae67e 66 * the card gets a read command, it responds with a response token, and then
psawant9 2:baca12fae67e 67 * a data token or an error.
psawant9 2:baca12fae67e 68 *
psawant9 2:baca12fae67e 69 * SPI Command Format
psawant9 2:baca12fae67e 70 * ------------------
psawant9 2:baca12fae67e 71 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
psawant9 2:baca12fae67e 72 *
psawant9 2:baca12fae67e 73 * +---------------+------------+------------+-----------+----------+--------------+
psawant9 2:baca12fae67e 74 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
psawant9 2:baca12fae67e 75 * +---------------+------------+------------+-----------+----------+--------------+
psawant9 2:baca12fae67e 76 *
psawant9 2:baca12fae67e 77 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
psawant9 2:baca12fae67e 78 *
psawant9 2:baca12fae67e 79 * All Application Specific commands shall be preceded with APP_CMD (CMD55).
psawant9 2:baca12fae67e 80 *
psawant9 2:baca12fae67e 81 * SPI Response Format
psawant9 2:baca12fae67e 82 * -------------------
psawant9 2:baca12fae67e 83 * The main response format (R1) is a status byte (normally zero). Key flags:
psawant9 2:baca12fae67e 84 * idle - 1 if the card is in an idle state/initialising
psawant9 2:baca12fae67e 85 * cmd - 1 if an illegal command code was detected
psawant9 2:baca12fae67e 86 *
psawant9 2:baca12fae67e 87 * +-------------------------------------------------+
psawant9 2:baca12fae67e 88 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
psawant9 2:baca12fae67e 89 * +-------------------------------------------------+
psawant9 2:baca12fae67e 90 *
psawant9 2:baca12fae67e 91 * R1b is the same, except it is followed by a busy signal (zeros) until
psawant9 2:baca12fae67e 92 * the first non-zero byte when it is ready again.
psawant9 2:baca12fae67e 93 *
psawant9 2:baca12fae67e 94 * Data Response Token
psawant9 2:baca12fae67e 95 * -------------------
psawant9 2:baca12fae67e 96 * Every data block written to the card is acknowledged by a byte
psawant9 2:baca12fae67e 97 * response token
psawant9 2:baca12fae67e 98 *
psawant9 2:baca12fae67e 99 * +----------------------+
psawant9 2:baca12fae67e 100 * | xxx | 0 | status | 1 |
psawant9 2:baca12fae67e 101 * +----------------------+
psawant9 2:baca12fae67e 102 * 010 - OK!
psawant9 2:baca12fae67e 103 * 101 - CRC Error
psawant9 2:baca12fae67e 104 * 110 - Write Error
psawant9 2:baca12fae67e 105 *
psawant9 2:baca12fae67e 106 * Single Block Read and Write
psawant9 2:baca12fae67e 107 * ---------------------------
psawant9 2:baca12fae67e 108 *
psawant9 2:baca12fae67e 109 * Block transfers have a byte header, followed by the data, followed
psawant9 2:baca12fae67e 110 * by a 16-bit CRC. In our case, the data will always be 512 bytes.
psawant9 2:baca12fae67e 111 *
psawant9 2:baca12fae67e 112 * +------+---------+---------+- - - -+---------+-----------+----------+
psawant9 2:baca12fae67e 113 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
psawant9 2:baca12fae67e 114 * +------+---------+---------+- - - -+---------+-----------+----------+
psawant9 2:baca12fae67e 115 */
psawant9 2:baca12fae67e 116
psawant9 2:baca12fae67e 117 #include "SDFileSystem.h"
psawant9 2:baca12fae67e 118
psawant9 2:baca12fae67e 119 #define SD_COMMAND_TIMEOUT 5000
psawant9 2:baca12fae67e 120
psawant9 2:baca12fae67e 121 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
psawant9 2:baca12fae67e 122 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
psawant9 2:baca12fae67e 123 _cs = 1;
psawant9 2:baca12fae67e 124 }
psawant9 2:baca12fae67e 125
psawant9 2:baca12fae67e 126 #define R1_IDLE_STATE (1 << 0)
psawant9 2:baca12fae67e 127 #define R1_ERASE_RESET (1 << 1)
psawant9 2:baca12fae67e 128 #define R1_ILLEGAL_COMMAND (1 << 2)
psawant9 2:baca12fae67e 129 #define R1_COM_CRC_ERROR (1 << 3)
psawant9 2:baca12fae67e 130 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
psawant9 2:baca12fae67e 131 #define R1_ADDRESS_ERROR (1 << 5)
psawant9 2:baca12fae67e 132 #define R1_PARAMETER_ERROR (1 << 6)
psawant9 2:baca12fae67e 133
psawant9 2:baca12fae67e 134 // Types
psawant9 2:baca12fae67e 135 // - v1.x Standard Capacity
psawant9 2:baca12fae67e 136 // - v2.x Standard Capacity
psawant9 2:baca12fae67e 137 // - v2.x High Capacity
psawant9 2:baca12fae67e 138 // - Not recognised as an SD Card
psawant9 2:baca12fae67e 139
psawant9 2:baca12fae67e 140 #define SDCARD_FAIL 0
psawant9 2:baca12fae67e 141 #define SDCARD_V1 1
psawant9 2:baca12fae67e 142 #define SDCARD_V2 2
psawant9 2:baca12fae67e 143 #define SDCARD_V2HC 3
psawant9 2:baca12fae67e 144
psawant9 2:baca12fae67e 145 int SDFileSystem::initialise_card() {
psawant9 2:baca12fae67e 146 // Set to 100kHz for initialisation, and clock card with cs = 1
psawant9 2:baca12fae67e 147 _spi.frequency(100000);
psawant9 2:baca12fae67e 148 _cs = 1;
psawant9 2:baca12fae67e 149 for(int i=0; i<16; i++) {
psawant9 2:baca12fae67e 150 _spi.write(0xFF);
psawant9 2:baca12fae67e 151 }
psawant9 2:baca12fae67e 152
psawant9 2:baca12fae67e 153 // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
psawant9 2:baca12fae67e 154 if(_cmd(0, 0) != R1_IDLE_STATE) {
psawant9 2:baca12fae67e 155 fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
psawant9 2:baca12fae67e 156 return SDCARD_FAIL;
psawant9 2:baca12fae67e 157 }
psawant9 2:baca12fae67e 158
psawant9 2:baca12fae67e 159 // send CMD8 to determine whther it is ver 2.x
psawant9 2:baca12fae67e 160 int r = _cmd8();
psawant9 2:baca12fae67e 161 if(r == R1_IDLE_STATE) {
psawant9 2:baca12fae67e 162 return initialise_card_v2();
psawant9 2:baca12fae67e 163 } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
psawant9 2:baca12fae67e 164 return initialise_card_v1();
psawant9 2:baca12fae67e 165 } else {
psawant9 2:baca12fae67e 166 fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
psawant9 2:baca12fae67e 167 return SDCARD_FAIL;
psawant9 2:baca12fae67e 168 }
psawant9 2:baca12fae67e 169 }
psawant9 2:baca12fae67e 170
psawant9 2:baca12fae67e 171 int SDFileSystem::initialise_card_v1() {
psawant9 2:baca12fae67e 172 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
psawant9 2:baca12fae67e 173 _cmd(55, 0);
psawant9 2:baca12fae67e 174 if(_cmd(41, 0) == 0) {
psawant9 2:baca12fae67e 175 return SDCARD_V1;
psawant9 2:baca12fae67e 176 }
psawant9 2:baca12fae67e 177 }
psawant9 2:baca12fae67e 178
psawant9 2:baca12fae67e 179 fprintf(stderr, "Timeout waiting for v1.x card\n");
psawant9 2:baca12fae67e 180 return SDCARD_FAIL;
psawant9 2:baca12fae67e 181 }
psawant9 2:baca12fae67e 182
psawant9 2:baca12fae67e 183 int SDFileSystem::initialise_card_v2() {
psawant9 2:baca12fae67e 184
psawant9 2:baca12fae67e 185 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
psawant9 2:baca12fae67e 186 _cmd(55, 0);
psawant9 2:baca12fae67e 187 if(_cmd(41, 0) == 0) {
psawant9 2:baca12fae67e 188 _cmd58();
psawant9 2:baca12fae67e 189 return SDCARD_V2;
psawant9 2:baca12fae67e 190 }
psawant9 2:baca12fae67e 191 }
psawant9 2:baca12fae67e 192
psawant9 2:baca12fae67e 193 fprintf(stderr, "Timeout waiting for v2.x card\n");
psawant9 2:baca12fae67e 194 return SDCARD_FAIL;
psawant9 2:baca12fae67e 195 }
psawant9 2:baca12fae67e 196
psawant9 2:baca12fae67e 197 int SDFileSystem::disk_initialize() {
psawant9 2:baca12fae67e 198
psawant9 2:baca12fae67e 199 int i = initialise_card();
psawant9 2:baca12fae67e 200 // printf("init card = %d\n", i);
psawant9 2:baca12fae67e 201 // printf("OK\n");
psawant9 2:baca12fae67e 202
psawant9 2:baca12fae67e 203 _sectors = _sd_sectors();
psawant9 2:baca12fae67e 204
psawant9 2:baca12fae67e 205 // Set block length to 512 (CMD16)
psawant9 2:baca12fae67e 206 if(_cmd(16, 512) != 0) {
psawant9 2:baca12fae67e 207 fprintf(stderr, "Set 512-byte block timed out\n");
psawant9 2:baca12fae67e 208 return 1;
psawant9 2:baca12fae67e 209 }
psawant9 2:baca12fae67e 210
psawant9 2:baca12fae67e 211 _spi.frequency(1000000); // Set to 1MHz for data transfer
psawant9 2:baca12fae67e 212 return 0;
psawant9 2:baca12fae67e 213 }
psawant9 2:baca12fae67e 214
psawant9 2:baca12fae67e 215 int SDFileSystem::disk_write(const char *buffer, int block_number) {
psawant9 2:baca12fae67e 216 // set write address for single block (CMD24)
psawant9 2:baca12fae67e 217 if(_cmd(24, block_number * 512) != 0) {
psawant9 2:baca12fae67e 218 return 1;
psawant9 2:baca12fae67e 219 }
psawant9 2:baca12fae67e 220
psawant9 2:baca12fae67e 221 // send the data block
psawant9 2:baca12fae67e 222 _write(buffer, 512);
psawant9 2:baca12fae67e 223 return 0;
psawant9 2:baca12fae67e 224 }
psawant9 2:baca12fae67e 225
psawant9 2:baca12fae67e 226 int SDFileSystem::disk_read(char *buffer, int block_number) {
psawant9 2:baca12fae67e 227 // set read address for single block (CMD17)
psawant9 2:baca12fae67e 228 if(_cmd(17, block_number * 512) != 0) {
psawant9 2:baca12fae67e 229 return 1;
psawant9 2:baca12fae67e 230 }
psawant9 2:baca12fae67e 231
psawant9 2:baca12fae67e 232 // receive the data
psawant9 2:baca12fae67e 233 _read(buffer, 512);
psawant9 2:baca12fae67e 234 return 0;
psawant9 2:baca12fae67e 235 }
psawant9 2:baca12fae67e 236
psawant9 2:baca12fae67e 237 int SDFileSystem::disk_status() { return 0; }
psawant9 2:baca12fae67e 238 int SDFileSystem::disk_sync() { return 0; }
psawant9 2:baca12fae67e 239 int SDFileSystem::disk_sectors() { return _sectors; }
psawant9 2:baca12fae67e 240
psawant9 2:baca12fae67e 241 // PRIVATE FUNCTIONS
psawant9 2:baca12fae67e 242
psawant9 2:baca12fae67e 243 int SDFileSystem::_cmd(int cmd, int arg) {
psawant9 2:baca12fae67e 244 _cs = 0;
psawant9 2:baca12fae67e 245
psawant9 2:baca12fae67e 246 // send a command
psawant9 2:baca12fae67e 247 _spi.write(0x40 | cmd);
psawant9 2:baca12fae67e 248 _spi.write(arg >> 24);
psawant9 2:baca12fae67e 249 _spi.write(arg >> 16);
psawant9 2:baca12fae67e 250 _spi.write(arg >> 8);
psawant9 2:baca12fae67e 251 _spi.write(arg >> 0);
psawant9 2:baca12fae67e 252 _spi.write(0x95);
psawant9 2:baca12fae67e 253
psawant9 2:baca12fae67e 254 // wait for the repsonse (response[7] == 0)
psawant9 2:baca12fae67e 255 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
psawant9 2:baca12fae67e 256 int response = _spi.write(0xFF);
psawant9 2:baca12fae67e 257 if(!(response & 0x80)) {
psawant9 2:baca12fae67e 258 _cs = 1;
psawant9 2:baca12fae67e 259 _spi.write(0xFF);
psawant9 2:baca12fae67e 260 return response;
psawant9 2:baca12fae67e 261 }
psawant9 2:baca12fae67e 262 }
psawant9 2:baca12fae67e 263 _cs = 1;
psawant9 2:baca12fae67e 264 _spi.write(0xFF);
psawant9 2:baca12fae67e 265 return -1; // timeout
psawant9 2:baca12fae67e 266 }
psawant9 2:baca12fae67e 267 int SDFileSystem::_cmdx(int cmd, int arg) {
psawant9 2:baca12fae67e 268 _cs = 0;
psawant9 2:baca12fae67e 269
psawant9 2:baca12fae67e 270 // send a command
psawant9 2:baca12fae67e 271 _spi.write(0x40 | cmd);
psawant9 2:baca12fae67e 272 _spi.write(arg >> 24);
psawant9 2:baca12fae67e 273 _spi.write(arg >> 16);
psawant9 2:baca12fae67e 274 _spi.write(arg >> 8);
psawant9 2:baca12fae67e 275 _spi.write(arg >> 0);
psawant9 2:baca12fae67e 276 _spi.write(0x95);
psawant9 2:baca12fae67e 277
psawant9 2:baca12fae67e 278 // wait for the repsonse (response[7] == 0)
psawant9 2:baca12fae67e 279 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
psawant9 2:baca12fae67e 280 int response = _spi.write(0xFF);
psawant9 2:baca12fae67e 281 if(!(response & 0x80)) {
psawant9 2:baca12fae67e 282 return response;
psawant9 2:baca12fae67e 283 }
psawant9 2:baca12fae67e 284 }
psawant9 2:baca12fae67e 285 _cs = 1;
psawant9 2:baca12fae67e 286 _spi.write(0xFF);
psawant9 2:baca12fae67e 287 return -1; // timeout
psawant9 2:baca12fae67e 288 }
psawant9 2:baca12fae67e 289
psawant9 2:baca12fae67e 290
psawant9 2:baca12fae67e 291 int SDFileSystem::_cmd58() {
psawant9 2:baca12fae67e 292 _cs = 0;
psawant9 2:baca12fae67e 293 int arg = 0;
psawant9 2:baca12fae67e 294
psawant9 2:baca12fae67e 295 // send a command
psawant9 2:baca12fae67e 296 _spi.write(0x40 | 58);
psawant9 2:baca12fae67e 297 _spi.write(arg >> 24);
psawant9 2:baca12fae67e 298 _spi.write(arg >> 16);
psawant9 2:baca12fae67e 299 _spi.write(arg >> 8);
psawant9 2:baca12fae67e 300 _spi.write(arg >> 0);
psawant9 2:baca12fae67e 301 _spi.write(0x95);
psawant9 2:baca12fae67e 302
psawant9 2:baca12fae67e 303 // wait for the repsonse (response[7] == 0)
psawant9 2:baca12fae67e 304 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
psawant9 2:baca12fae67e 305 int response = _spi.write(0xFF);
psawant9 2:baca12fae67e 306 if(!(response & 0x80)) {
psawant9 2:baca12fae67e 307 int ocr = _spi.write(0xFF) << 24;
psawant9 2:baca12fae67e 308 ocr |= _spi.write(0xFF) << 16;
psawant9 2:baca12fae67e 309 ocr |= _spi.write(0xFF) << 8;
psawant9 2:baca12fae67e 310 ocr |= _spi.write(0xFF) << 0;
psawant9 2:baca12fae67e 311 // printf("OCR = 0x%08X\n", ocr);
psawant9 2:baca12fae67e 312 _cs = 1;
psawant9 2:baca12fae67e 313 _spi.write(0xFF);
psawant9 2:baca12fae67e 314 return response;
psawant9 2:baca12fae67e 315 }
psawant9 2:baca12fae67e 316 }
psawant9 2:baca12fae67e 317 _cs = 1;
psawant9 2:baca12fae67e 318 _spi.write(0xFF);
psawant9 2:baca12fae67e 319 return -1; // timeout
psawant9 2:baca12fae67e 320 }
psawant9 2:baca12fae67e 321
psawant9 2:baca12fae67e 322 int SDFileSystem::_cmd8() {
psawant9 2:baca12fae67e 323 _cs = 0;
psawant9 2:baca12fae67e 324
psawant9 2:baca12fae67e 325 // send a command
psawant9 2:baca12fae67e 326 _spi.write(0x40 | 8); // CMD8
psawant9 2:baca12fae67e 327 _spi.write(0x00); // reserved
psawant9 2:baca12fae67e 328 _spi.write(0x00); // reserved
psawant9 2:baca12fae67e 329 _spi.write(0x01); // 3.3v
psawant9 2:baca12fae67e 330 _spi.write(0xAA); // check pattern
psawant9 2:baca12fae67e 331 _spi.write(0x87); // crc
psawant9 2:baca12fae67e 332
psawant9 2:baca12fae67e 333 // wait for the repsonse (response[7] == 0)
psawant9 2:baca12fae67e 334 for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
psawant9 2:baca12fae67e 335 char response[5];
psawant9 2:baca12fae67e 336 response[0] = _spi.write(0xFF);
psawant9 2:baca12fae67e 337 if(!(response[0] & 0x80)) {
psawant9 2:baca12fae67e 338 for(int j=1; j<5; j++) {
psawant9 2:baca12fae67e 339 response[i] = _spi.write(0xFF);
psawant9 2:baca12fae67e 340 }
psawant9 2:baca12fae67e 341 _cs = 1;
psawant9 2:baca12fae67e 342 _spi.write(0xFF);
psawant9 2:baca12fae67e 343 return response[0];
psawant9 2:baca12fae67e 344 }
psawant9 2:baca12fae67e 345 }
psawant9 2:baca12fae67e 346 _cs = 1;
psawant9 2:baca12fae67e 347 _spi.write(0xFF);
psawant9 2:baca12fae67e 348 return -1; // timeout
psawant9 2:baca12fae67e 349 }
psawant9 2:baca12fae67e 350
psawant9 2:baca12fae67e 351 int SDFileSystem::_read(char *buffer, int length) {
psawant9 2:baca12fae67e 352 _cs = 0;
psawant9 2:baca12fae67e 353
psawant9 2:baca12fae67e 354 // read until start byte (0xFF)
psawant9 2:baca12fae67e 355 while(_spi.write(0xFF) != 0xFE);
psawant9 2:baca12fae67e 356
psawant9 2:baca12fae67e 357 // read data
psawant9 2:baca12fae67e 358 for(int i=0; i<length; i++) {
psawant9 2:baca12fae67e 359 buffer[i] = _spi.write(0xFF);
psawant9 2:baca12fae67e 360 }
psawant9 2:baca12fae67e 361 _spi.write(0xFF); // checksum
psawant9 2:baca12fae67e 362 _spi.write(0xFF);
psawant9 2:baca12fae67e 363
psawant9 2:baca12fae67e 364 _cs = 1;
psawant9 2:baca12fae67e 365 _spi.write(0xFF);
psawant9 2:baca12fae67e 366 return 0;
psawant9 2:baca12fae67e 367 }
psawant9 2:baca12fae67e 368
psawant9 2:baca12fae67e 369 int SDFileSystem::_write(const char *buffer, int length) {
psawant9 2:baca12fae67e 370 _cs = 0;
psawant9 2:baca12fae67e 371
psawant9 2:baca12fae67e 372 // indicate start of block
psawant9 2:baca12fae67e 373 _spi.write(0xFE);
psawant9 2:baca12fae67e 374
psawant9 2:baca12fae67e 375 // write the data
psawant9 2:baca12fae67e 376 for(int i=0; i<length; i++) {
psawant9 2:baca12fae67e 377 _spi.write(buffer[i]);
psawant9 2:baca12fae67e 378 }
psawant9 2:baca12fae67e 379
psawant9 2:baca12fae67e 380 // write the checksum
psawant9 2:baca12fae67e 381 _spi.write(0xFF);
psawant9 2:baca12fae67e 382 _spi.write(0xFF);
psawant9 2:baca12fae67e 383
psawant9 2:baca12fae67e 384 // check the repsonse token
psawant9 2:baca12fae67e 385 if((_spi.write(0xFF) & 0x1F) != 0x05) {
psawant9 2:baca12fae67e 386 _cs = 1;
psawant9 2:baca12fae67e 387 _spi.write(0xFF);
psawant9 2:baca12fae67e 388 return 1;
psawant9 2:baca12fae67e 389 }
psawant9 2:baca12fae67e 390
psawant9 2:baca12fae67e 391 // wait for write to finish
psawant9 2:baca12fae67e 392 while(_spi.write(0xFF) == 0);
psawant9 2:baca12fae67e 393
psawant9 2:baca12fae67e 394 _cs = 1;
psawant9 2:baca12fae67e 395 _spi.write(0xFF);
psawant9 2:baca12fae67e 396 return 0;
psawant9 2:baca12fae67e 397 }
psawant9 2:baca12fae67e 398
psawant9 2:baca12fae67e 399 static int ext_bits(char *data, int msb, int lsb) {
psawant9 2:baca12fae67e 400 int bits = 0;
psawant9 2:baca12fae67e 401 int size = 1 + msb - lsb;
psawant9 2:baca12fae67e 402 for(int i=0; i<size; i++) {
psawant9 2:baca12fae67e 403 int position = lsb + i;
psawant9 2:baca12fae67e 404 int byte = 15 - (position >> 3);
psawant9 2:baca12fae67e 405 int bit = position & 0x7;
psawant9 2:baca12fae67e 406 int value = (data[byte] >> bit) & 1;
psawant9 2:baca12fae67e 407 bits |= value << i;
psawant9 2:baca12fae67e 408 }
psawant9 2:baca12fae67e 409 return bits;
psawant9 2:baca12fae67e 410 }
psawant9 2:baca12fae67e 411
psawant9 2:baca12fae67e 412 int SDFileSystem::_sd_sectors() {
psawant9 2:baca12fae67e 413
psawant9 2:baca12fae67e 414 // CMD9, Response R2 (R1 byte + 16-byte block read)
psawant9 2:baca12fae67e 415 if(_cmdx(9, 0) != 0) {
psawant9 2:baca12fae67e 416 fprintf(stderr, "Didn't get a response from the disk\n");
psawant9 2:baca12fae67e 417 return 0;
psawant9 2:baca12fae67e 418 }
psawant9 2:baca12fae67e 419
psawant9 2:baca12fae67e 420 char csd[16];
psawant9 2:baca12fae67e 421 if(_read(csd, 16) != 0) {
psawant9 2:baca12fae67e 422 fprintf(stderr, "Couldn't read csd response from disk\n");
psawant9 2:baca12fae67e 423 return 0;
psawant9 2:baca12fae67e 424 }
psawant9 2:baca12fae67e 425
psawant9 2:baca12fae67e 426 // csd_structure : csd[127:126]
psawant9 2:baca12fae67e 427 // c_size : csd[73:62]
psawant9 2:baca12fae67e 428 // c_size_mult : csd[49:47]
psawant9 2:baca12fae67e 429 // read_bl_len : csd[83:80] - the *maximum* read block length
psawant9 2:baca12fae67e 430
psawant9 2:baca12fae67e 431 int csd_structure = ext_bits(csd, 127, 126);
psawant9 2:baca12fae67e 432 int c_size = ext_bits(csd, 73, 62);
psawant9 2:baca12fae67e 433 int c_size_mult = ext_bits(csd, 49, 47);
psawant9 2:baca12fae67e 434 int read_bl_len = ext_bits(csd, 83, 80);
psawant9 2:baca12fae67e 435
psawant9 2:baca12fae67e 436 // printf("CSD_STRUCT = %d\n", csd_structure);
psawant9 2:baca12fae67e 437
psawant9 2:baca12fae67e 438 if(csd_structure != 0) {
psawant9 2:baca12fae67e 439 fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
psawant9 2:baca12fae67e 440 return 0;
psawant9 2:baca12fae67e 441 }
psawant9 2:baca12fae67e 442
psawant9 2:baca12fae67e 443 // memory capacity = BLOCKNR * BLOCK_LEN
psawant9 2:baca12fae67e 444 // where
psawant9 2:baca12fae67e 445 // BLOCKNR = (C_SIZE+1) * MULT
psawant9 2:baca12fae67e 446 // MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
psawant9 2:baca12fae67e 447 // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
psawant9 2:baca12fae67e 448
psawant9 2:baca12fae67e 449 int block_len = 1 << read_bl_len;
psawant9 2:baca12fae67e 450 int mult = 1 << (c_size_mult + 2);
psawant9 2:baca12fae67e 451 int blocknr = (c_size + 1) * mult;
psawant9 2:baca12fae67e 452 int capacity = blocknr * block_len;
psawant9 2:baca12fae67e 453
psawant9 2:baca12fae67e 454 int blocks = capacity / 512;
psawant9 2:baca12fae67e 455
psawant9 2:baca12fae67e 456 return blocks;
psawant9 2:baca12fae67e 457 }