mbed Weather Platform SD memory logger

Dependencies:   mbed

Committer:
okini3939
Date:
Wed Dec 01 14:27:29 2010 +0000
Revision:
1:14bf00e73e45
Parent:
0:88b426acd89c

        

Who changed what in which revision?

UserRevisionLine numberNew contents of line
okini3939 0:88b426acd89c 1 /* mbed SDFileSystem Library, for providing file access to SD cards
okini3939 0:88b426acd89c 2 * Copyright (c) 2008-2010, sford
okini3939 0:88b426acd89c 3 *
okini3939 0:88b426acd89c 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
okini3939 0:88b426acd89c 5 * of this software and associated documentation files (the "Software"), to deal
okini3939 0:88b426acd89c 6 * in the Software without restriction, including without limitation the rights
okini3939 0:88b426acd89c 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
okini3939 0:88b426acd89c 8 * copies of the Software, and to permit persons to whom the Software is
okini3939 0:88b426acd89c 9 * furnished to do so, subject to the following conditions:
okini3939 0:88b426acd89c 10 *
okini3939 0:88b426acd89c 11 * The above copyright notice and this permission notice shall be included in
okini3939 0:88b426acd89c 12 * all copies or substantial portions of the Software.
okini3939 0:88b426acd89c 13 *
okini3939 0:88b426acd89c 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
okini3939 0:88b426acd89c 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
okini3939 0:88b426acd89c 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
okini3939 0:88b426acd89c 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
okini3939 0:88b426acd89c 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
okini3939 0:88b426acd89c 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
okini3939 0:88b426acd89c 20 * THE SOFTWARE.
okini3939 0:88b426acd89c 21 */
okini3939 0:88b426acd89c 22
okini3939 0:88b426acd89c 23 /* Introduction
okini3939 0:88b426acd89c 24 * ------------
okini3939 0:88b426acd89c 25 * SD and MMC cards support a number of interfaces, but common to them all
okini3939 0:88b426acd89c 26 * is one based on SPI. This is the one I'm implmenting because it means
okini3939 0:88b426acd89c 27 * it is much more portable even though not so performant, and we already
okini3939 0:88b426acd89c 28 * have the mbed SPI Interface!
okini3939 0:88b426acd89c 29 *
okini3939 0:88b426acd89c 30 * The main reference I'm using is Chapter 7, "SPI Mode" of:
okini3939 0:88b426acd89c 31 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
okini3939 0:88b426acd89c 32 *
okini3939 0:88b426acd89c 33 * SPI Startup
okini3939 0:88b426acd89c 34 * -----------
okini3939 0:88b426acd89c 35 * The SD card powers up in SD mode. The SPI interface mode is selected by
okini3939 0:88b426acd89c 36 * asserting CS low and sending the reset command (CMD0). The card will
okini3939 0:88b426acd89c 37 * respond with a (R1) response.
okini3939 0:88b426acd89c 38 *
okini3939 0:88b426acd89c 39 * CMD8 is optionally sent to determine the voltage range supported, and
okini3939 0:88b426acd89c 40 * indirectly determine whether it is a version 1.x SD/non-SD card or
okini3939 0:88b426acd89c 41 * version 2.x. I'll just ignore this for now.
okini3939 0:88b426acd89c 42 *
okini3939 0:88b426acd89c 43 * ACMD41 is repeatedly issued to initialise the card, until "in idle"
okini3939 0:88b426acd89c 44 * (bit 0) of the R1 response goes to '0', indicating it is initialised.
okini3939 0:88b426acd89c 45 *
okini3939 0:88b426acd89c 46 * You should also indicate whether the host supports High Capicity cards,
okini3939 0:88b426acd89c 47 * and check whether the card is high capacity - i'll also ignore this
okini3939 0:88b426acd89c 48 *
okini3939 0:88b426acd89c 49 * SPI Protocol
okini3939 0:88b426acd89c 50 * ------------
okini3939 0:88b426acd89c 51 * The SD SPI protocol is based on transactions made up of 8-bit words, with
okini3939 0:88b426acd89c 52 * the host starting every bus transaction by asserting the CS signal low. The
okini3939 0:88b426acd89c 53 * card always responds to commands, data blocks and errors.
okini3939 0:88b426acd89c 54 *
okini3939 0:88b426acd89c 55 * The protocol supports a CRC, but by default it is off (except for the
okini3939 0:88b426acd89c 56 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
okini3939 0:88b426acd89c 57 * I'll leave the CRC off I think!
okini3939 0:88b426acd89c 58 *
okini3939 0:88b426acd89c 59 * Standard capacity cards have variable data block sizes, whereas High
okini3939 0:88b426acd89c 60 * Capacity cards fix the size of data block to 512 bytes. I'll therefore
okini3939 0:88b426acd89c 61 * just always use the Standard Capacity cards with a block size of 512 bytes.
okini3939 0:88b426acd89c 62 * This is set with CMD16.
okini3939 0:88b426acd89c 63 *
okini3939 0:88b426acd89c 64 * You can read and write single blocks (CMD17, CMD25) or multiple blocks
okini3939 0:88b426acd89c 65 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
okini3939 0:88b426acd89c 66 * the card gets a read command, it responds with a response token, and then
okini3939 0:88b426acd89c 67 * a data token or an error.
okini3939 0:88b426acd89c 68 *
okini3939 0:88b426acd89c 69 * SPI Command Format
okini3939 0:88b426acd89c 70 * ------------------
okini3939 0:88b426acd89c 71 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
okini3939 0:88b426acd89c 72 *
okini3939 0:88b426acd89c 73 * +---------------+------------+------------+-----------+----------+--------------+
okini3939 0:88b426acd89c 74 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
okini3939 0:88b426acd89c 75 * +---------------+------------+------------+-----------+----------+--------------+
okini3939 0:88b426acd89c 76 *
okini3939 0:88b426acd89c 77 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
okini3939 0:88b426acd89c 78 *
okini3939 0:88b426acd89c 79 * All Application Specific commands shall be preceded with APP_CMD (CMD55).
okini3939 0:88b426acd89c 80 *
okini3939 0:88b426acd89c 81 * SPI Response Format
okini3939 0:88b426acd89c 82 * -------------------
okini3939 0:88b426acd89c 83 * The main response format (R1) is a status byte (normally zero). Key flags:
okini3939 0:88b426acd89c 84 * idle - 1 if the card is in an idle state/initialising
okini3939 0:88b426acd89c 85 * cmd - 1 if an illegal command code was detected
okini3939 0:88b426acd89c 86 *
okini3939 0:88b426acd89c 87 * +-------------------------------------------------+
okini3939 0:88b426acd89c 88 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
okini3939 0:88b426acd89c 89 * +-------------------------------------------------+
okini3939 0:88b426acd89c 90 *
okini3939 0:88b426acd89c 91 * R1b is the same, except it is followed by a busy signal (zeros) until
okini3939 0:88b426acd89c 92 * the first non-zero byte when it is ready again.
okini3939 0:88b426acd89c 93 *
okini3939 0:88b426acd89c 94 * Data Response Token
okini3939 0:88b426acd89c 95 * -------------------
okini3939 0:88b426acd89c 96 * Every data block written to the card is acknowledged by a byte
okini3939 0:88b426acd89c 97 * response token
okini3939 0:88b426acd89c 98 *
okini3939 0:88b426acd89c 99 * +----------------------+
okini3939 0:88b426acd89c 100 * | xxx | 0 | status | 1 |
okini3939 0:88b426acd89c 101 * +----------------------+
okini3939 0:88b426acd89c 102 * 010 - OK!
okini3939 0:88b426acd89c 103 * 101 - CRC Error
okini3939 0:88b426acd89c 104 * 110 - Write Error
okini3939 0:88b426acd89c 105 *
okini3939 0:88b426acd89c 106 * Single Block Read and Write
okini3939 0:88b426acd89c 107 * ---------------------------
okini3939 0:88b426acd89c 108 *
okini3939 0:88b426acd89c 109 * Block transfers have a byte header, followed by the data, followed
okini3939 0:88b426acd89c 110 * by a 16-bit CRC. In our case, the data will always be 512 bytes.
okini3939 0:88b426acd89c 111 *
okini3939 0:88b426acd89c 112 * +------+---------+---------+- - - -+---------+-----------+----------+
okini3939 0:88b426acd89c 113 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
okini3939 0:88b426acd89c 114 * +------+---------+---------+- - - -+---------+-----------+----------+
okini3939 0:88b426acd89c 115 */
okini3939 0:88b426acd89c 116
okini3939 0:88b426acd89c 117 #include "SDFileSystem.h"
okini3939 0:88b426acd89c 118
okini3939 0:88b426acd89c 119 #define SD_COMMAND_TIMEOUT 5000
okini3939 0:88b426acd89c 120
okini3939 0:88b426acd89c 121 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
okini3939 0:88b426acd89c 122 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
okini3939 0:88b426acd89c 123 _cs = 1;
okini3939 0:88b426acd89c 124 }
okini3939 0:88b426acd89c 125
okini3939 0:88b426acd89c 126 #define R1_IDLE_STATE (1 << 0)
okini3939 0:88b426acd89c 127 #define R1_ERASE_RESET (1 << 1)
okini3939 0:88b426acd89c 128 #define R1_ILLEGAL_COMMAND (1 << 2)
okini3939 0:88b426acd89c 129 #define R1_COM_CRC_ERROR (1 << 3)
okini3939 0:88b426acd89c 130 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
okini3939 0:88b426acd89c 131 #define R1_ADDRESS_ERROR (1 << 5)
okini3939 0:88b426acd89c 132 #define R1_PARAMETER_ERROR (1 << 6)
okini3939 0:88b426acd89c 133
okini3939 0:88b426acd89c 134 // Types
okini3939 0:88b426acd89c 135 // - v1.x Standard Capacity
okini3939 0:88b426acd89c 136 // - v2.x Standard Capacity
okini3939 0:88b426acd89c 137 // - v2.x High Capacity
okini3939 0:88b426acd89c 138 // - Not recognised as an SD Card
okini3939 0:88b426acd89c 139
okini3939 0:88b426acd89c 140 #define SDCARD_FAIL 0
okini3939 0:88b426acd89c 141 #define SDCARD_V1 1
okini3939 0:88b426acd89c 142 #define SDCARD_V2 2
okini3939 0:88b426acd89c 143 #define SDCARD_V2HC 3
okini3939 0:88b426acd89c 144
okini3939 0:88b426acd89c 145 int SDFileSystem::initialise_card() {
okini3939 0:88b426acd89c 146 // Set to 100kHz for initialisation, and clock card with cs = 1
okini3939 0:88b426acd89c 147 _spi.frequency(100000);
okini3939 0:88b426acd89c 148 _cs = 1;
okini3939 0:88b426acd89c 149 for(int i=0; i<16; i++) {
okini3939 0:88b426acd89c 150 _spi.write(0xFF);
okini3939 0:88b426acd89c 151 }
okini3939 0:88b426acd89c 152
okini3939 0:88b426acd89c 153 // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
okini3939 0:88b426acd89c 154 if(_cmd(0, 0) != R1_IDLE_STATE) {
okini3939 0:88b426acd89c 155 fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
okini3939 0:88b426acd89c 156 return SDCARD_FAIL;
okini3939 0:88b426acd89c 157 }
okini3939 0:88b426acd89c 158
okini3939 0:88b426acd89c 159 // send CMD8 to determine whther it is ver 2.x
okini3939 0:88b426acd89c 160 int r = _cmd8();
okini3939 0:88b426acd89c 161 if(r == R1_IDLE_STATE) {
okini3939 0:88b426acd89c 162 return initialise_card_v2();
okini3939 0:88b426acd89c 163 } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
okini3939 0:88b426acd89c 164 return initialise_card_v1();
okini3939 0:88b426acd89c 165 } else {
okini3939 0:88b426acd89c 166 fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
okini3939 0:88b426acd89c 167 return SDCARD_FAIL;
okini3939 0:88b426acd89c 168 }
okini3939 0:88b426acd89c 169 }
okini3939 0:88b426acd89c 170
okini3939 0:88b426acd89c 171 int SDFileSystem::initialise_card_v1() {
okini3939 0:88b426acd89c 172 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:88b426acd89c 173 _cmd(55, 0);
okini3939 0:88b426acd89c 174 if(_cmd(41, 0) == 0) {
okini3939 0:88b426acd89c 175 return SDCARD_V1;
okini3939 0:88b426acd89c 176 }
okini3939 0:88b426acd89c 177 }
okini3939 0:88b426acd89c 178
okini3939 0:88b426acd89c 179 fprintf(stderr, "Timeout waiting for v1.x card\n");
okini3939 0:88b426acd89c 180 return SDCARD_FAIL;
okini3939 0:88b426acd89c 181 }
okini3939 0:88b426acd89c 182
okini3939 0:88b426acd89c 183 int SDFileSystem::initialise_card_v2() {
okini3939 0:88b426acd89c 184
okini3939 0:88b426acd89c 185 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:88b426acd89c 186 _cmd(55, 0);
okini3939 0:88b426acd89c 187 if(_cmd(41, 0) == 0) {
okini3939 0:88b426acd89c 188 _cmd58();
okini3939 0:88b426acd89c 189 return SDCARD_V2;
okini3939 0:88b426acd89c 190 }
okini3939 0:88b426acd89c 191 }
okini3939 0:88b426acd89c 192
okini3939 0:88b426acd89c 193 fprintf(stderr, "Timeout waiting for v2.x card\n");
okini3939 0:88b426acd89c 194 return SDCARD_FAIL;
okini3939 0:88b426acd89c 195 }
okini3939 0:88b426acd89c 196
okini3939 0:88b426acd89c 197 int SDFileSystem::disk_initialize() {
okini3939 0:88b426acd89c 198
okini3939 0:88b426acd89c 199 int i = initialise_card();
okini3939 0:88b426acd89c 200 // printf("init card = %d\n", i);
okini3939 0:88b426acd89c 201 // printf("OK\n");
okini3939 0:88b426acd89c 202
okini3939 0:88b426acd89c 203 _sectors = _sd_sectors();
okini3939 0:88b426acd89c 204
okini3939 0:88b426acd89c 205 // Set block length to 512 (CMD16)
okini3939 0:88b426acd89c 206 if(_cmd(16, 512) != 0) {
okini3939 0:88b426acd89c 207 fprintf(stderr, "Set 512-byte block timed out\n");
okini3939 0:88b426acd89c 208 return 1;
okini3939 0:88b426acd89c 209 }
okini3939 0:88b426acd89c 210
okini3939 0:88b426acd89c 211 _spi.frequency(1000000); // Set to 1MHz for data transfer
okini3939 0:88b426acd89c 212 return 0;
okini3939 0:88b426acd89c 213 }
okini3939 0:88b426acd89c 214
okini3939 0:88b426acd89c 215 int SDFileSystem::disk_write(const char *buffer, int block_number) {
okini3939 0:88b426acd89c 216 // set write address for single block (CMD24)
okini3939 0:88b426acd89c 217 if(_cmd(24, block_number * 512) != 0) {
okini3939 0:88b426acd89c 218 return 1;
okini3939 0:88b426acd89c 219 }
okini3939 0:88b426acd89c 220
okini3939 0:88b426acd89c 221 // send the data block
okini3939 0:88b426acd89c 222 _write(buffer, 512);
okini3939 0:88b426acd89c 223 return 0;
okini3939 0:88b426acd89c 224 }
okini3939 0:88b426acd89c 225
okini3939 0:88b426acd89c 226 int SDFileSystem::disk_read(char *buffer, int block_number) {
okini3939 0:88b426acd89c 227 // set read address for single block (CMD17)
okini3939 0:88b426acd89c 228 if(_cmd(17, block_number * 512) != 0) {
okini3939 0:88b426acd89c 229 return 1;
okini3939 0:88b426acd89c 230 }
okini3939 0:88b426acd89c 231
okini3939 0:88b426acd89c 232 // receive the data
okini3939 0:88b426acd89c 233 _read(buffer, 512);
okini3939 0:88b426acd89c 234 return 0;
okini3939 0:88b426acd89c 235 }
okini3939 0:88b426acd89c 236
okini3939 0:88b426acd89c 237 int SDFileSystem::disk_status() { return 0; }
okini3939 0:88b426acd89c 238 int SDFileSystem::disk_sync() { return 0; }
okini3939 0:88b426acd89c 239 int SDFileSystem::disk_sectors() { return _sectors; }
okini3939 0:88b426acd89c 240
okini3939 0:88b426acd89c 241 // PRIVATE FUNCTIONS
okini3939 0:88b426acd89c 242
okini3939 0:88b426acd89c 243 int SDFileSystem::_cmd(int cmd, int arg) {
okini3939 0:88b426acd89c 244 _cs = 0;
okini3939 0:88b426acd89c 245
okini3939 0:88b426acd89c 246 // send a command
okini3939 0:88b426acd89c 247 _spi.write(0x40 | cmd);
okini3939 0:88b426acd89c 248 _spi.write(arg >> 24);
okini3939 0:88b426acd89c 249 _spi.write(arg >> 16);
okini3939 0:88b426acd89c 250 _spi.write(arg >> 8);
okini3939 0:88b426acd89c 251 _spi.write(arg >> 0);
okini3939 0:88b426acd89c 252 _spi.write(0x95);
okini3939 0:88b426acd89c 253
okini3939 0:88b426acd89c 254 // wait for the repsonse (response[7] == 0)
okini3939 0:88b426acd89c 255 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:88b426acd89c 256 int response = _spi.write(0xFF);
okini3939 0:88b426acd89c 257 if(!(response & 0x80)) {
okini3939 0:88b426acd89c 258 _cs = 1;
okini3939 0:88b426acd89c 259 _spi.write(0xFF);
okini3939 0:88b426acd89c 260 return response;
okini3939 0:88b426acd89c 261 }
okini3939 0:88b426acd89c 262 }
okini3939 0:88b426acd89c 263 _cs = 1;
okini3939 0:88b426acd89c 264 _spi.write(0xFF);
okini3939 0:88b426acd89c 265 return -1; // timeout
okini3939 0:88b426acd89c 266 }
okini3939 0:88b426acd89c 267 int SDFileSystem::_cmdx(int cmd, int arg) {
okini3939 0:88b426acd89c 268 _cs = 0;
okini3939 0:88b426acd89c 269
okini3939 0:88b426acd89c 270 // send a command
okini3939 0:88b426acd89c 271 _spi.write(0x40 | cmd);
okini3939 0:88b426acd89c 272 _spi.write(arg >> 24);
okini3939 0:88b426acd89c 273 _spi.write(arg >> 16);
okini3939 0:88b426acd89c 274 _spi.write(arg >> 8);
okini3939 0:88b426acd89c 275 _spi.write(arg >> 0);
okini3939 0:88b426acd89c 276 _spi.write(0x95);
okini3939 0:88b426acd89c 277
okini3939 0:88b426acd89c 278 // wait for the repsonse (response[7] == 0)
okini3939 0:88b426acd89c 279 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:88b426acd89c 280 int response = _spi.write(0xFF);
okini3939 0:88b426acd89c 281 if(!(response & 0x80)) {
okini3939 0:88b426acd89c 282 return response;
okini3939 0:88b426acd89c 283 }
okini3939 0:88b426acd89c 284 }
okini3939 0:88b426acd89c 285 _cs = 1;
okini3939 0:88b426acd89c 286 _spi.write(0xFF);
okini3939 0:88b426acd89c 287 return -1; // timeout
okini3939 0:88b426acd89c 288 }
okini3939 0:88b426acd89c 289
okini3939 0:88b426acd89c 290
okini3939 0:88b426acd89c 291 int SDFileSystem::_cmd58() {
okini3939 0:88b426acd89c 292 _cs = 0;
okini3939 0:88b426acd89c 293 int arg = 0;
okini3939 0:88b426acd89c 294
okini3939 0:88b426acd89c 295 // send a command
okini3939 0:88b426acd89c 296 _spi.write(0x40 | 58);
okini3939 0:88b426acd89c 297 _spi.write(arg >> 24);
okini3939 0:88b426acd89c 298 _spi.write(arg >> 16);
okini3939 0:88b426acd89c 299 _spi.write(arg >> 8);
okini3939 0:88b426acd89c 300 _spi.write(arg >> 0);
okini3939 0:88b426acd89c 301 _spi.write(0x95);
okini3939 0:88b426acd89c 302
okini3939 0:88b426acd89c 303 // wait for the repsonse (response[7] == 0)
okini3939 0:88b426acd89c 304 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:88b426acd89c 305 int response = _spi.write(0xFF);
okini3939 0:88b426acd89c 306 if(!(response & 0x80)) {
okini3939 0:88b426acd89c 307 int ocr = _spi.write(0xFF) << 24;
okini3939 0:88b426acd89c 308 ocr |= _spi.write(0xFF) << 16;
okini3939 0:88b426acd89c 309 ocr |= _spi.write(0xFF) << 8;
okini3939 0:88b426acd89c 310 ocr |= _spi.write(0xFF) << 0;
okini3939 0:88b426acd89c 311 // printf("OCR = 0x%08X\n", ocr);
okini3939 0:88b426acd89c 312 _cs = 1;
okini3939 0:88b426acd89c 313 _spi.write(0xFF);
okini3939 0:88b426acd89c 314 return response;
okini3939 0:88b426acd89c 315 }
okini3939 0:88b426acd89c 316 }
okini3939 0:88b426acd89c 317 _cs = 1;
okini3939 0:88b426acd89c 318 _spi.write(0xFF);
okini3939 0:88b426acd89c 319 return -1; // timeout
okini3939 0:88b426acd89c 320 }
okini3939 0:88b426acd89c 321
okini3939 0:88b426acd89c 322 int SDFileSystem::_cmd8() {
okini3939 0:88b426acd89c 323 _cs = 0;
okini3939 0:88b426acd89c 324
okini3939 0:88b426acd89c 325 // send a command
okini3939 0:88b426acd89c 326 _spi.write(0x40 | 8); // CMD8
okini3939 0:88b426acd89c 327 _spi.write(0x00); // reserved
okini3939 0:88b426acd89c 328 _spi.write(0x00); // reserved
okini3939 0:88b426acd89c 329 _spi.write(0x01); // 3.3v
okini3939 0:88b426acd89c 330 _spi.write(0xAA); // check pattern
okini3939 0:88b426acd89c 331 _spi.write(0x87); // crc
okini3939 0:88b426acd89c 332
okini3939 0:88b426acd89c 333 // wait for the repsonse (response[7] == 0)
okini3939 0:88b426acd89c 334 for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
okini3939 0:88b426acd89c 335 char response[5];
okini3939 0:88b426acd89c 336 response[0] = _spi.write(0xFF);
okini3939 0:88b426acd89c 337 if(!(response[0] & 0x80)) {
okini3939 0:88b426acd89c 338 for(int j=1; j<5; j++) {
okini3939 0:88b426acd89c 339 response[i] = _spi.write(0xFF);
okini3939 0:88b426acd89c 340 }
okini3939 0:88b426acd89c 341 _cs = 1;
okini3939 0:88b426acd89c 342 _spi.write(0xFF);
okini3939 0:88b426acd89c 343 return response[0];
okini3939 0:88b426acd89c 344 }
okini3939 0:88b426acd89c 345 }
okini3939 0:88b426acd89c 346 _cs = 1;
okini3939 0:88b426acd89c 347 _spi.write(0xFF);
okini3939 0:88b426acd89c 348 return -1; // timeout
okini3939 0:88b426acd89c 349 }
okini3939 0:88b426acd89c 350
okini3939 0:88b426acd89c 351 int SDFileSystem::_read(char *buffer, int length) {
okini3939 0:88b426acd89c 352 _cs = 0;
okini3939 0:88b426acd89c 353
okini3939 0:88b426acd89c 354 // read until start byte (0xFF)
okini3939 0:88b426acd89c 355 while(_spi.write(0xFF) != 0xFE);
okini3939 0:88b426acd89c 356
okini3939 0:88b426acd89c 357 // read data
okini3939 0:88b426acd89c 358 for(int i=0; i<length; i++) {
okini3939 0:88b426acd89c 359 buffer[i] = _spi.write(0xFF);
okini3939 0:88b426acd89c 360 }
okini3939 0:88b426acd89c 361 _spi.write(0xFF); // checksum
okini3939 0:88b426acd89c 362 _spi.write(0xFF);
okini3939 0:88b426acd89c 363
okini3939 0:88b426acd89c 364 _cs = 1;
okini3939 0:88b426acd89c 365 _spi.write(0xFF);
okini3939 0:88b426acd89c 366 return 0;
okini3939 0:88b426acd89c 367 }
okini3939 0:88b426acd89c 368
okini3939 0:88b426acd89c 369 int SDFileSystem::_write(const char *buffer, int length) {
okini3939 0:88b426acd89c 370 _cs = 0;
okini3939 0:88b426acd89c 371
okini3939 0:88b426acd89c 372 // indicate start of block
okini3939 0:88b426acd89c 373 _spi.write(0xFE);
okini3939 0:88b426acd89c 374
okini3939 0:88b426acd89c 375 // write the data
okini3939 0:88b426acd89c 376 for(int i=0; i<length; i++) {
okini3939 0:88b426acd89c 377 _spi.write(buffer[i]);
okini3939 0:88b426acd89c 378 }
okini3939 0:88b426acd89c 379
okini3939 0:88b426acd89c 380 // write the checksum
okini3939 0:88b426acd89c 381 _spi.write(0xFF);
okini3939 0:88b426acd89c 382 _spi.write(0xFF);
okini3939 0:88b426acd89c 383
okini3939 0:88b426acd89c 384 // check the repsonse token
okini3939 0:88b426acd89c 385 if((_spi.write(0xFF) & 0x1F) != 0x05) {
okini3939 0:88b426acd89c 386 _cs = 1;
okini3939 0:88b426acd89c 387 _spi.write(0xFF);
okini3939 0:88b426acd89c 388 return 1;
okini3939 0:88b426acd89c 389 }
okini3939 0:88b426acd89c 390
okini3939 0:88b426acd89c 391 // wait for write to finish
okini3939 0:88b426acd89c 392 while(_spi.write(0xFF) == 0);
okini3939 0:88b426acd89c 393
okini3939 0:88b426acd89c 394 _cs = 1;
okini3939 0:88b426acd89c 395 _spi.write(0xFF);
okini3939 0:88b426acd89c 396 return 0;
okini3939 0:88b426acd89c 397 }
okini3939 0:88b426acd89c 398
okini3939 0:88b426acd89c 399 static int ext_bits(char *data, int msb, int lsb) {
okini3939 0:88b426acd89c 400 int bits = 0;
okini3939 0:88b426acd89c 401 int size = 1 + msb - lsb;
okini3939 0:88b426acd89c 402 for(int i=0; i<size; i++) {
okini3939 0:88b426acd89c 403 int position = lsb + i;
okini3939 0:88b426acd89c 404 int byte = 15 - (position >> 3);
okini3939 0:88b426acd89c 405 int bit = position & 0x7;
okini3939 0:88b426acd89c 406 int value = (data[byte] >> bit) & 1;
okini3939 0:88b426acd89c 407 bits |= value << i;
okini3939 0:88b426acd89c 408 }
okini3939 0:88b426acd89c 409 return bits;
okini3939 0:88b426acd89c 410 }
okini3939 0:88b426acd89c 411
okini3939 0:88b426acd89c 412 int SDFileSystem::_sd_sectors() {
okini3939 0:88b426acd89c 413
okini3939 0:88b426acd89c 414 // CMD9, Response R2 (R1 byte + 16-byte block read)
okini3939 0:88b426acd89c 415 if(_cmdx(9, 0) != 0) {
okini3939 0:88b426acd89c 416 fprintf(stderr, "Didn't get a response from the disk\n");
okini3939 0:88b426acd89c 417 return 0;
okini3939 0:88b426acd89c 418 }
okini3939 0:88b426acd89c 419
okini3939 0:88b426acd89c 420 char csd[16];
okini3939 0:88b426acd89c 421 if(_read(csd, 16) != 0) {
okini3939 0:88b426acd89c 422 fprintf(stderr, "Couldn't read csd response from disk\n");
okini3939 0:88b426acd89c 423 return 0;
okini3939 0:88b426acd89c 424 }
okini3939 0:88b426acd89c 425
okini3939 0:88b426acd89c 426 // csd_structure : csd[127:126]
okini3939 0:88b426acd89c 427 // c_size : csd[73:62]
okini3939 0:88b426acd89c 428 // c_size_mult : csd[49:47]
okini3939 0:88b426acd89c 429 // read_bl_len : csd[83:80] - the *maximum* read block length
okini3939 0:88b426acd89c 430
okini3939 0:88b426acd89c 431 int csd_structure = ext_bits(csd, 127, 126);
okini3939 0:88b426acd89c 432 int c_size = ext_bits(csd, 73, 62);
okini3939 0:88b426acd89c 433 int c_size_mult = ext_bits(csd, 49, 47);
okini3939 0:88b426acd89c 434 int read_bl_len = ext_bits(csd, 83, 80);
okini3939 0:88b426acd89c 435
okini3939 0:88b426acd89c 436 // printf("CSD_STRUCT = %d\n", csd_structure);
okini3939 0:88b426acd89c 437
okini3939 0:88b426acd89c 438 if(csd_structure != 0) {
okini3939 0:88b426acd89c 439 fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
okini3939 0:88b426acd89c 440 return 0;
okini3939 0:88b426acd89c 441 }
okini3939 0:88b426acd89c 442
okini3939 0:88b426acd89c 443 // memory capacity = BLOCKNR * BLOCK_LEN
okini3939 0:88b426acd89c 444 // where
okini3939 0:88b426acd89c 445 // BLOCKNR = (C_SIZE+1) * MULT
okini3939 0:88b426acd89c 446 // MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
okini3939 0:88b426acd89c 447 // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
okini3939 0:88b426acd89c 448
okini3939 0:88b426acd89c 449 int block_len = 1 << read_bl_len;
okini3939 0:88b426acd89c 450 int mult = 1 << (c_size_mult + 2);
okini3939 0:88b426acd89c 451 int blocknr = (c_size + 1) * mult;
okini3939 0:88b426acd89c 452 int capacity = blocknr * block_len;
okini3939 0:88b426acd89c 453
okini3939 0:88b426acd89c 454 int blocks = capacity / 512;
okini3939 0:88b426acd89c 455
okini3939 0:88b426acd89c 456 return blocks;
okini3939 0:88b426acd89c 457 }