Dave Van Wagner / SDHCFileSystem

private Library copy of SDHCFileSystem

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SDHCFileSystem.cpp@0:248d03543f5f, 2011-02-27 (annotated)

Committer:
davervw
Date:
Sun Feb 27 18:51:31 2011 +0000
Revision:
0:248d03543f5f
revised to make into library, address compiler warnings, turn off DEBUG

Who changed what in which revision?

UserRevisionLine numberNew contents of line
davervw 0:248d03543f5f 1 /* mbed SDFileSystem Library, for providing file access to SD cards
davervw 0:248d03543f5f 2 * Copyright (c) 2008-2010, sford
davervw 0:248d03543f5f 3 *
davervw 0:248d03543f5f 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
davervw 0:248d03543f5f 5 * of this software and associated documentation files (the "Software"), to deal
davervw 0:248d03543f5f 6 * in the Software without restriction, including without limitation the rights
davervw 0:248d03543f5f 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
davervw 0:248d03543f5f 8 * copies of the Software, and to permit persons to whom the Software is
davervw 0:248d03543f5f 9 * furnished to do so, subject to the following conditions:
davervw 0:248d03543f5f 10 *
davervw 0:248d03543f5f 11 * The above copyright notice and this permission notice shall be included in
davervw 0:248d03543f5f 12 * all copies or substantial portions of the Software.
davervw 0:248d03543f5f 13 *
davervw 0:248d03543f5f 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
davervw 0:248d03543f5f 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
davervw 0:248d03543f5f 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
davervw 0:248d03543f5f 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
davervw 0:248d03543f5f 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
davervw 0:248d03543f5f 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
davervw 0:248d03543f5f 20 * THE SOFTWARE.
davervw 0:248d03543f5f 21 */
davervw 0:248d03543f5f 22
davervw 0:248d03543f5f 23 /* Introduction
davervw 0:248d03543f5f 24 * ------------
davervw 0:248d03543f5f 25 * SD and MMC cards support a number of interfaces, but common to them all
davervw 0:248d03543f5f 26 * is one based on SPI. This is the one I'm implmenting because it means
davervw 0:248d03543f5f 27 * it is much more portable even though not so performant, and we already
davervw 0:248d03543f5f 28 * have the mbed SPI Interface!
davervw 0:248d03543f5f 29 *
davervw 0:248d03543f5f 30 * The main reference I'm using is Chapter 7, "SPI Mode" of:
davervw 0:248d03543f5f 31 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
davervw 0:248d03543f5f 32 *
davervw 0:248d03543f5f 33 * SPI Startup
davervw 0:248d03543f5f 34 * -----------
davervw 0:248d03543f5f 35 * The SD card powers up in SD mode. The SPI interface mode is selected by
davervw 0:248d03543f5f 36 * asserting CS low and sending the reset command (CMD0). The card will
davervw 0:248d03543f5f 37 * respond with a (R1) response.
davervw 0:248d03543f5f 38 *
davervw 0:248d03543f5f 39 * CMD8 is optionally sent to determine the voltage range supported, and
davervw 0:248d03543f5f 40 * indirectly determine whether it is a version 1.x SD/non-SD card or
davervw 0:248d03543f5f 41 * version 2.x. I'll just ignore this for now.
davervw 0:248d03543f5f 42 *
davervw 0:248d03543f5f 43 * ACMD41 is repeatedly issued to initialise the card, until "in idle"
davervw 0:248d03543f5f 44 * (bit 0) of the R1 response goes to '0', indicating it is initialised.
davervw 0:248d03543f5f 45 *
davervw 0:248d03543f5f 46 * You should also indicate whether the host supports High Capicity cards,
davervw 0:248d03543f5f 47 * and check whether the card is high capacity - i'll also ignore this
davervw 0:248d03543f5f 48 *
davervw 0:248d03543f5f 49 * SPI Protocol
davervw 0:248d03543f5f 50 * ------------
davervw 0:248d03543f5f 51 * The SD SPI protocol is based on transactions made up of 8-bit words, with
davervw 0:248d03543f5f 52 * the host starting every bus transaction by asserting the CS signal low. The
davervw 0:248d03543f5f 53 * card always responds to commands, data blocks and errors.
davervw 0:248d03543f5f 54 *
davervw 0:248d03543f5f 55 * The protocol supports a CRC, but by default it is off (except for the
davervw 0:248d03543f5f 56 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
davervw 0:248d03543f5f 57 * I'll leave the CRC off I think!
davervw 0:248d03543f5f 58 *
davervw 0:248d03543f5f 59 * Standard capacity cards have variable data block sizes, whereas High
davervw 0:248d03543f5f 60 * Capacity cards fix the size of data block to 512 bytes. I'll therefore
davervw 0:248d03543f5f 61 * just always use the Standard Capacity cards with a block size of 512 bytes.
davervw 0:248d03543f5f 62 * This is set with CMD16.
davervw 0:248d03543f5f 63 *
davervw 0:248d03543f5f 64 * You can read and write single blocks (CMD17, CMD25) or multiple blocks
davervw 0:248d03543f5f 65 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
davervw 0:248d03543f5f 66 * the card gets a read command, it responds with a response token, and then
davervw 0:248d03543f5f 67 * a data token or an error.
davervw 0:248d03543f5f 68 *
davervw 0:248d03543f5f 69 * SPI Command Format
davervw 0:248d03543f5f 70 * ------------------
davervw 0:248d03543f5f 71 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
davervw 0:248d03543f5f 72 *
davervw 0:248d03543f5f 73 * +---------------+------------+------------+-----------+----------+--------------+
davervw 0:248d03543f5f 74 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
davervw 0:248d03543f5f 75 * +---------------+------------+------------+-----------+----------+--------------+
davervw 0:248d03543f5f 76 *
davervw 0:248d03543f5f 77 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
davervw 0:248d03543f5f 78 *
davervw 0:248d03543f5f 79 * All Application Specific commands shall be preceded with APP_CMD (CMD55).
davervw 0:248d03543f5f 80 *
davervw 0:248d03543f5f 81 * SPI Response Format
davervw 0:248d03543f5f 82 * -------------------
davervw 0:248d03543f5f 83 * The main response format (R1) is a status byte (normally zero). Key flags:
davervw 0:248d03543f5f 84 * idle - 1 if the card is in an idle state/initialising
davervw 0:248d03543f5f 85 * cmd - 1 if an illegal command code was detected
davervw 0:248d03543f5f 86 *
davervw 0:248d03543f5f 87 * +-------------------------------------------------+
davervw 0:248d03543f5f 88 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
davervw 0:248d03543f5f 89 * +-------------------------------------------------+
davervw 0:248d03543f5f 90 *
davervw 0:248d03543f5f 91 * R1b is the same, except it is followed by a busy signal (zeros) until
davervw 0:248d03543f5f 92 * the first non-zero byte when it is ready again.
davervw 0:248d03543f5f 93 *
davervw 0:248d03543f5f 94 * Data Response Token
davervw 0:248d03543f5f 95 * -------------------
davervw 0:248d03543f5f 96 * Every data block written to the card is acknowledged by a byte
davervw 0:248d03543f5f 97 * response token
davervw 0:248d03543f5f 98 *
davervw 0:248d03543f5f 99 * +----------------------+
davervw 0:248d03543f5f 100 * | xxx | 0 | status | 1 |
davervw 0:248d03543f5f 101 * +----------------------+
davervw 0:248d03543f5f 102 * 010 - OK!
davervw 0:248d03543f5f 103 * 101 - CRC Error
davervw 0:248d03543f5f 104 * 110 - Write Error
davervw 0:248d03543f5f 105 *
davervw 0:248d03543f5f 106 * Single Block Read and Write
davervw 0:248d03543f5f 107 * ---------------------------
davervw 0:248d03543f5f 108 *
davervw 0:248d03543f5f 109 * Block transfers have a byte header, followed by the data, followed
davervw 0:248d03543f5f 110 * by a 16-bit CRC. In our case, the data will always be 512 bytes.
davervw 0:248d03543f5f 111 *
davervw 0:248d03543f5f 112 * +------+---------+---------+- - - -+---------+-----------+----------+
davervw 0:248d03543f5f 113 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
davervw 0:248d03543f5f 114 * +------+---------+---------+- - - -+---------+-----------+----------+
davervw 0:248d03543f5f 115 */
davervw 0:248d03543f5f 116
davervw 0:248d03543f5f 117 /*
davervw 0:248d03543f5f 118 * Comment: Changes for SDHC support till 32GB
davervw 0:248d03543f5f 119 * Name: KB
davervw 0:248d03543f5f 120 * Date: 07/24/2010
davervw 0:248d03543f5f 121 * Release: 0.1
davervw 0:248d03543f5f 122 */
davervw 0:248d03543f5f 123
davervw 0:248d03543f5f 124 /*
davervw 0:248d03543f5f 125 * Comment: Fixing compiler warnings, turning off DEBUG define
davervw 0:248d03543f5f 126 * Name: davervw
davervw 0:248d03543f5f 127 * Date: 02/26/2011
davervw 0:248d03543f5f 128 */
davervw 0:248d03543f5f 129
davervw 0:248d03543f5f 130 #include "SDHCFileSystem.h"
davervw 0:248d03543f5f 131
davervw 0:248d03543f5f 132 //#define DEBUG
davervw 0:248d03543f5f 133 #define SD_COMMAND_TIMEOUT 5000
davervw 0:248d03543f5f 134
davervw 0:248d03543f5f 135
davervw 0:248d03543f5f 136 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
davervw 0:248d03543f5f 137 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
davervw 0:248d03543f5f 138 _cs = 1;
davervw 0:248d03543f5f 139 }
davervw 0:248d03543f5f 140
davervw 0:248d03543f5f 141 #define R1_IDLE_STATE (1 << 0)
davervw 0:248d03543f5f 142 #define R1_ERASE_RESET (1 << 1)
davervw 0:248d03543f5f 143 #define R1_ILLEGAL_COMMAND (1 << 2)
davervw 0:248d03543f5f 144 #define R1_COM_CRC_ERROR (1 << 3)
davervw 0:248d03543f5f 145 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
davervw 0:248d03543f5f 146 #define R1_ADDRESS_ERROR (1 << 5)
davervw 0:248d03543f5f 147 #define R1_PARAMETER_ERROR (1 << 6)
davervw 0:248d03543f5f 148
davervw 0:248d03543f5f 149 // Types
davervw 0:248d03543f5f 150 // - v1.x Standard Capacity
davervw 0:248d03543f5f 151 // - v2.x Standard Capacity
davervw 0:248d03543f5f 152 // - v2.x High Capacity
davervw 0:248d03543f5f 153 // - Not recognised as an SD Card
davervw 0:248d03543f5f 154
davervw 0:248d03543f5f 155 #define SDCARD_FAIL 0
davervw 0:248d03543f5f 156 #define SDCARD_V1 1
davervw 0:248d03543f5f 157 #define SDCARD_V2 2
davervw 0:248d03543f5f 158 #define SDCARD_V2HC 3
davervw 0:248d03543f5f 159
davervw 0:248d03543f5f 160 int SDFileSystem::initialise_card() {
davervw 0:248d03543f5f 161 // Set to 100kHz for initialisation, and clock card with cs = 1
davervw 0:248d03543f5f 162 _spi.frequency(100000);
davervw 0:248d03543f5f 163 _cs = 1;
davervw 0:248d03543f5f 164 for(int i=0; i<16; i++) {
davervw 0:248d03543f5f 165 _spi.write(0xFF);
davervw 0:248d03543f5f 166 }
davervw 0:248d03543f5f 167
davervw 0:248d03543f5f 168 // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
davervw 0:248d03543f5f 169 if(_cmd(0, 0) != R1_IDLE_STATE) {
davervw 0:248d03543f5f 170 fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
davervw 0:248d03543f5f 171 return SDCARD_FAIL;
davervw 0:248d03543f5f 172 }
davervw 0:248d03543f5f 173
davervw 0:248d03543f5f 174 // send CMD8 to determine whther it is ver 2.x
davervw 0:248d03543f5f 175 int r = _cmd8();
davervw 0:248d03543f5f 176 if(r == R1_IDLE_STATE) {
davervw 0:248d03543f5f 177 return initialise_card_v2();
davervw 0:248d03543f5f 178 } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
davervw 0:248d03543f5f 179 return initialise_card_v1();
davervw 0:248d03543f5f 180 } else {
davervw 0:248d03543f5f 181 fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
davervw 0:248d03543f5f 182 return SDCARD_FAIL;
davervw 0:248d03543f5f 183 }
davervw 0:248d03543f5f 184 }
davervw 0:248d03543f5f 185
davervw 0:248d03543f5f 186 int SDFileSystem::initialise_card_v1() {
davervw 0:248d03543f5f 187 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
davervw 0:248d03543f5f 188 _cmd(55, 0);
davervw 0:248d03543f5f 189 if(_cmd(41, 0) == 0) {
davervw 0:248d03543f5f 190 cdv = 512;
davervw 0:248d03543f5f 191 #ifdef DEBUG
davervw 0:248d03543f5f 192 printf("\n\rInit: SEDCARD_V1\n\r");
davervw 0:248d03543f5f 193 #endif
davervw 0:248d03543f5f 194 return SDCARD_V1;
davervw 0:248d03543f5f 195 }
davervw 0:248d03543f5f 196 }
davervw 0:248d03543f5f 197
davervw 0:248d03543f5f 198 fprintf(stderr, "Timeout waiting for v1.x card\n");
davervw 0:248d03543f5f 199 return SDCARD_FAIL;
davervw 0:248d03543f5f 200 }
davervw 0:248d03543f5f 201
davervw 0:248d03543f5f 202 int SDFileSystem::initialise_card_v2() {
davervw 0:248d03543f5f 203
davervw 0:248d03543f5f 204 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
davervw 0:248d03543f5f 205 wait_ms(50);
davervw 0:248d03543f5f 206 _cmd58();
davervw 0:248d03543f5f 207 _cmd(55, 0);
davervw 0:248d03543f5f 208 if(_cmd(41, 0x40000000) == 0) {
davervw 0:248d03543f5f 209 _cmd58();
davervw 0:248d03543f5f 210 #ifdef DEBUG
davervw 0:248d03543f5f 211 printf("\n\rInit: SDCARD_V2\n\r");
davervw 0:248d03543f5f 212 #endif
davervw 0:248d03543f5f 213 cdv = 1;
davervw 0:248d03543f5f 214 return SDCARD_V2;
davervw 0:248d03543f5f 215 }
davervw 0:248d03543f5f 216 }
davervw 0:248d03543f5f 217
davervw 0:248d03543f5f 218 fprintf(stderr, "Timeout waiting for v2.x card\n");
davervw 0:248d03543f5f 219 return SDCARD_FAIL;
davervw 0:248d03543f5f 220 }
davervw 0:248d03543f5f 221
davervw 0:248d03543f5f 222 int SDFileSystem::disk_initialize() {
davervw 0:248d03543f5f 223
davervw 0:248d03543f5f 224 int i = initialise_card();
davervw 0:248d03543f5f 225 #ifdef DEBUG
davervw 0:248d03543f5f 226 printf("init card = %d\n", i);
davervw 0:248d03543f5f 227 #endif
davervw 0:248d03543f5f 228 _sectors = _sd_sectors();
davervw 0:248d03543f5f 229
davervw 0:248d03543f5f 230 // Set block length to 512 (CMD16)
davervw 0:248d03543f5f 231 if(_cmd(16, 512) != 0) {
davervw 0:248d03543f5f 232 fprintf(stderr, "Set 512-byte block timed out\n");
davervw 0:248d03543f5f 233 return 1;
davervw 0:248d03543f5f 234 }
davervw 0:248d03543f5f 235
davervw 0:248d03543f5f 236 _spi.frequency(1000000); // Set to 1MHz for data transfer
davervw 0:248d03543f5f 237 return 0;
davervw 0:248d03543f5f 238 }
davervw 0:248d03543f5f 239
davervw 0:248d03543f5f 240 int SDFileSystem::disk_write(const char *buffer, int block_number) {
davervw 0:248d03543f5f 241 // set write address for single block (CMD24)
davervw 0:248d03543f5f 242 if(_cmd(24, block_number * cdv) != 0) {
davervw 0:248d03543f5f 243 return 1;
davervw 0:248d03543f5f 244 }
davervw 0:248d03543f5f 245
davervw 0:248d03543f5f 246 // send the data block
davervw 0:248d03543f5f 247 _write(buffer, 512);
davervw 0:248d03543f5f 248 return 0;
davervw 0:248d03543f5f 249 }
davervw 0:248d03543f5f 250
davervw 0:248d03543f5f 251 int SDFileSystem::disk_read(char *buffer, int block_number) {
davervw 0:248d03543f5f 252 // set read address for single block (CMD17)
davervw 0:248d03543f5f 253 if(_cmd(17, block_number * cdv) != 0) {
davervw 0:248d03543f5f 254 return 1;
davervw 0:248d03543f5f 255 }
davervw 0:248d03543f5f 256
davervw 0:248d03543f5f 257 // receive the data
davervw 0:248d03543f5f 258 _read(buffer, 512);
davervw 0:248d03543f5f 259 return 0;
davervw 0:248d03543f5f 260 }
davervw 0:248d03543f5f 261
davervw 0:248d03543f5f 262 int SDFileSystem::disk_status() { return 0; }
davervw 0:248d03543f5f 263 int SDFileSystem::disk_sync() { return 0; }
davervw 0:248d03543f5f 264 int SDFileSystem::disk_sectors() { return _sectors; }
davervw 0:248d03543f5f 265
davervw 0:248d03543f5f 266 // PRIVATE FUNCTIONS
davervw 0:248d03543f5f 267
davervw 0:248d03543f5f 268 int SDFileSystem::_cmd(int cmd, int arg) {
davervw 0:248d03543f5f 269 _cs = 0;
davervw 0:248d03543f5f 270
davervw 0:248d03543f5f 271 // send a command
davervw 0:248d03543f5f 272 _spi.write(0x40 | cmd);
davervw 0:248d03543f5f 273 _spi.write(arg >> 24);
davervw 0:248d03543f5f 274 _spi.write(arg >> 16);
davervw 0:248d03543f5f 275 _spi.write(arg >> 8);
davervw 0:248d03543f5f 276 _spi.write(arg >> 0);
davervw 0:248d03543f5f 277 _spi.write(0x95);
davervw 0:248d03543f5f 278
davervw 0:248d03543f5f 279 // wait for the repsonse (response[7] == 0)
davervw 0:248d03543f5f 280 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
davervw 0:248d03543f5f 281 int response = _spi.write(0xFF);
davervw 0:248d03543f5f 282 if(!(response & 0x80)) {
davervw 0:248d03543f5f 283 _cs = 1;
davervw 0:248d03543f5f 284 _spi.write(0xFF);
davervw 0:248d03543f5f 285 return response;
davervw 0:248d03543f5f 286 }
davervw 0:248d03543f5f 287 }
davervw 0:248d03543f5f 288 _cs = 1;
davervw 0:248d03543f5f 289 _spi.write(0xFF);
davervw 0:248d03543f5f 290 return -1; // timeout
davervw 0:248d03543f5f 291 }
davervw 0:248d03543f5f 292 int SDFileSystem::_cmdx(int cmd, int arg) {
davervw 0:248d03543f5f 293 _cs = 0;
davervw 0:248d03543f5f 294
davervw 0:248d03543f5f 295 // send a command
davervw 0:248d03543f5f 296 _spi.write(0x40 | cmd);
davervw 0:248d03543f5f 297 _spi.write(arg >> 24);
davervw 0:248d03543f5f 298 _spi.write(arg >> 16);
davervw 0:248d03543f5f 299 _spi.write(arg >> 8);
davervw 0:248d03543f5f 300 _spi.write(arg >> 0);
davervw 0:248d03543f5f 301 _spi.write(0x95);
davervw 0:248d03543f5f 302
davervw 0:248d03543f5f 303 // wait for the repsonse (response[7] == 0)
davervw 0:248d03543f5f 304 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
davervw 0:248d03543f5f 305 int response = _spi.write(0xFF);
davervw 0:248d03543f5f 306 if(!(response & 0x80)) {
davervw 0:248d03543f5f 307 return response;
davervw 0:248d03543f5f 308 }
davervw 0:248d03543f5f 309 }
davervw 0:248d03543f5f 310 _cs = 1;
davervw 0:248d03543f5f 311 _spi.write(0xFF);
davervw 0:248d03543f5f 312 return -1; // timeout
davervw 0:248d03543f5f 313 }
davervw 0:248d03543f5f 314
davervw 0:248d03543f5f 315
davervw 0:248d03543f5f 316 int SDFileSystem::_cmd58() {
davervw 0:248d03543f5f 317 _cs = 0;
davervw 0:248d03543f5f 318 int arg = 0;
davervw 0:248d03543f5f 319
davervw 0:248d03543f5f 320 // send a command
davervw 0:248d03543f5f 321 _spi.write(0x40 | 58);
davervw 0:248d03543f5f 322 _spi.write(arg >> 24);
davervw 0:248d03543f5f 323 _spi.write(arg >> 16);
davervw 0:248d03543f5f 324 _spi.write(arg >> 8);
davervw 0:248d03543f5f 325 _spi.write(arg >> 0);
davervw 0:248d03543f5f 326 _spi.write(0x95);
davervw 0:248d03543f5f 327
davervw 0:248d03543f5f 328 // wait for the repsonse (response[7] == 0)
davervw 0:248d03543f5f 329 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
davervw 0:248d03543f5f 330 int response = _spi.write(0xFF);
davervw 0:248d03543f5f 331 if(!(response & 0x80)) {
davervw 0:248d03543f5f 332 int ocr = _spi.write(0xFF) << 24;
davervw 0:248d03543f5f 333 ocr |= _spi.write(0xFF) << 16;
davervw 0:248d03543f5f 334 ocr |= _spi.write(0xFF) << 8;
davervw 0:248d03543f5f 335 ocr |= _spi.write(0xFF) << 0;
davervw 0:248d03543f5f 336 // printf("OCR = 0x%08X\n", ocr);
davervw 0:248d03543f5f 337 _cs = 1;
davervw 0:248d03543f5f 338 _spi.write(0xFF);
davervw 0:248d03543f5f 339 return response;
davervw 0:248d03543f5f 340 }
davervw 0:248d03543f5f 341 }
davervw 0:248d03543f5f 342 _cs = 1;
davervw 0:248d03543f5f 343 _spi.write(0xFF);
davervw 0:248d03543f5f 344 return -1; // timeout
davervw 0:248d03543f5f 345 }
davervw 0:248d03543f5f 346
davervw 0:248d03543f5f 347 int SDFileSystem::_cmd8() {
davervw 0:248d03543f5f 348 _cs = 0;
davervw 0:248d03543f5f 349
davervw 0:248d03543f5f 350 // send a command
davervw 0:248d03543f5f 351 _spi.write(0x40 | 8); // CMD8
davervw 0:248d03543f5f 352 _spi.write(0x00); // reserved
davervw 0:248d03543f5f 353 _spi.write(0x00); // reserved
davervw 0:248d03543f5f 354 _spi.write(0x01); // 3.3v
davervw 0:248d03543f5f 355 _spi.write(0xAA); // check pattern
davervw 0:248d03543f5f 356 _spi.write(0x87); // crc
davervw 0:248d03543f5f 357
davervw 0:248d03543f5f 358 // wait for the repsonse (response[7] == 0)
davervw 0:248d03543f5f 359 for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
davervw 0:248d03543f5f 360 char response[5];
davervw 0:248d03543f5f 361 response[0] = _spi.write(0xFF);
davervw 0:248d03543f5f 362 if(!(response[0] & 0x80)) {
davervw 0:248d03543f5f 363 for(int j=1; j<5; j++) {
davervw 0:248d03543f5f 364 response[i] = _spi.write(0xFF);
davervw 0:248d03543f5f 365 }
davervw 0:248d03543f5f 366 _cs = 1;
davervw 0:248d03543f5f 367 _spi.write(0xFF);
davervw 0:248d03543f5f 368 return response[0];
davervw 0:248d03543f5f 369 }
davervw 0:248d03543f5f 370 }
davervw 0:248d03543f5f 371 _cs = 1;
davervw 0:248d03543f5f 372 _spi.write(0xFF);
davervw 0:248d03543f5f 373 return -1; // timeout
davervw 0:248d03543f5f 374 }
davervw 0:248d03543f5f 375
davervw 0:248d03543f5f 376 int SDFileSystem::_read(char *buffer, int length) {
davervw 0:248d03543f5f 377 _cs = 0;
davervw 0:248d03543f5f 378
davervw 0:248d03543f5f 379 // read until start byte (0xFF)
davervw 0:248d03543f5f 380 while(_spi.write(0xFF) != 0xFE);
davervw 0:248d03543f5f 381
davervw 0:248d03543f5f 382 // read data
davervw 0:248d03543f5f 383 for(int i=0; i<length; i++) {
davervw 0:248d03543f5f 384 buffer[i] = _spi.write(0xFF);
davervw 0:248d03543f5f 385 }
davervw 0:248d03543f5f 386 _spi.write(0xFF); // checksum
davervw 0:248d03543f5f 387 _spi.write(0xFF);
davervw 0:248d03543f5f 388
davervw 0:248d03543f5f 389 _cs = 1;
davervw 0:248d03543f5f 390 _spi.write(0xFF);
davervw 0:248d03543f5f 391 return 0;
davervw 0:248d03543f5f 392 }
davervw 0:248d03543f5f 393
davervw 0:248d03543f5f 394 int SDFileSystem::_write(const char *buffer, int length) {
davervw 0:248d03543f5f 395 _cs = 0;
davervw 0:248d03543f5f 396
davervw 0:248d03543f5f 397 // indicate start of block
davervw 0:248d03543f5f 398 _spi.write(0xFE);
davervw 0:248d03543f5f 399
davervw 0:248d03543f5f 400 // write the data
davervw 0:248d03543f5f 401 for(int i=0; i<length; i++) {
davervw 0:248d03543f5f 402 _spi.write(buffer[i]);
davervw 0:248d03543f5f 403 }
davervw 0:248d03543f5f 404
davervw 0:248d03543f5f 405 // write the checksum
davervw 0:248d03543f5f 406 _spi.write(0xFF);
davervw 0:248d03543f5f 407 _spi.write(0xFF);
davervw 0:248d03543f5f 408
davervw 0:248d03543f5f 409 // check the repsonse token
davervw 0:248d03543f5f 410 if((_spi.write(0xFF) & 0x1F) != 0x05) {
davervw 0:248d03543f5f 411 _cs = 1;
davervw 0:248d03543f5f 412 _spi.write(0xFF);
davervw 0:248d03543f5f 413 return 1;
davervw 0:248d03543f5f 414 }
davervw 0:248d03543f5f 415
davervw 0:248d03543f5f 416 // wait for write to finish
davervw 0:248d03543f5f 417 while(_spi.write(0xFF) == 0);
davervw 0:248d03543f5f 418
davervw 0:248d03543f5f 419 _cs = 1;
davervw 0:248d03543f5f 420 _spi.write(0xFF);
davervw 0:248d03543f5f 421 return 0;
davervw 0:248d03543f5f 422 }
davervw 0:248d03543f5f 423
davervw 0:248d03543f5f 424 static int ext_bits(char *data, int msb, int lsb) {
davervw 0:248d03543f5f 425 int bits = 0;
davervw 0:248d03543f5f 426 int size = 1 + msb - lsb;
davervw 0:248d03543f5f 427 for(int i=0; i<size; i++) {
davervw 0:248d03543f5f 428 int position = lsb + i;
davervw 0:248d03543f5f 429 int byte = 15 - (position >> 3);
davervw 0:248d03543f5f 430 int bit = position & 0x7;
davervw 0:248d03543f5f 431 int value = (data[byte] >> bit) & 1;
davervw 0:248d03543f5f 432 bits |= value << i;
davervw 0:248d03543f5f 433 }
davervw 0:248d03543f5f 434 return bits;
davervw 0:248d03543f5f 435 }
davervw 0:248d03543f5f 436
davervw 0:248d03543f5f 437 int SDFileSystem::_sd_sectors() {
davervw 0:248d03543f5f 438
davervw 0:248d03543f5f 439 int c_size, c_size_mult, read_bl_len;
davervw 0:248d03543f5f 440 int block_len, mult, blocknr, capacity;
davervw 0:248d03543f5f 441 int blocks, hc_c_size;
davervw 0:248d03543f5f 442
davervw 0:248d03543f5f 443 // CMD9, Response R2 (R1 byte + 16-byte block read)
davervw 0:248d03543f5f 444 if(_cmdx(9, 0) != 0) {
davervw 0:248d03543f5f 445 fprintf(stderr, "Didn't get a response from the disk\n");
davervw 0:248d03543f5f 446 return 0;
davervw 0:248d03543f5f 447 }
davervw 0:248d03543f5f 448
davervw 0:248d03543f5f 449 char csd[16];
davervw 0:248d03543f5f 450 if(_read(csd, 16) != 0) {
davervw 0:248d03543f5f 451 fprintf(stderr, "Couldn't read csd response from disk\n");
davervw 0:248d03543f5f 452 return 0;
davervw 0:248d03543f5f 453 }
davervw 0:248d03543f5f 454
davervw 0:248d03543f5f 455 // csd_structure : csd[127:126]
davervw 0:248d03543f5f 456 // c_size : csd[73:62]
davervw 0:248d03543f5f 457 // c_size_mult : csd[49:47]
davervw 0:248d03543f5f 458 // read_bl_len : csd[83:80] - the *maximum* read block length
davervw 0:248d03543f5f 459
davervw 0:248d03543f5f 460 int csd_structure = ext_bits(csd, 127, 126);
davervw 0:248d03543f5f 461
davervw 0:248d03543f5f 462 #ifdef DEBUG
davervw 0:248d03543f5f 463 printf("\n\rCSD_STRUCT = %d\n", csd_structure);
davervw 0:248d03543f5f 464 #endif
davervw 0:248d03543f5f 465
davervw 0:248d03543f5f 466 switch (csd_structure){
davervw 0:248d03543f5f 467 case 0:
davervw 0:248d03543f5f 468 cdv = 512;
davervw 0:248d03543f5f 469 c_size = ext_bits(csd, 73, 62);
davervw 0:248d03543f5f 470 c_size_mult = ext_bits(csd, 49, 47);
davervw 0:248d03543f5f 471 read_bl_len = ext_bits(csd, 83, 80);
davervw 0:248d03543f5f 472
davervw 0:248d03543f5f 473 block_len = 1 << read_bl_len;
davervw 0:248d03543f5f 474 mult = 1 << (c_size_mult + 2);
davervw 0:248d03543f5f 475 blocknr = (c_size + 1) * mult;
davervw 0:248d03543f5f 476 capacity = blocknr * block_len;
davervw 0:248d03543f5f 477 blocks = capacity / 512;
davervw 0:248d03543f5f 478 #ifdef DEBUG
davervw 0:248d03543f5f 479 printf("\n\rSDCard\n\rc_size: %.4X \n\rcapacity: %.ld \n\rsectors: %d\n\r", c_size, capacity, blocks);
davervw 0:248d03543f5f 480 #endif
davervw 0:248d03543f5f 481 break;
davervw 0:248d03543f5f 482
davervw 0:248d03543f5f 483 case 1:
davervw 0:248d03543f5f 484 {
davervw 0:248d03543f5f 485 cdv = 1;
davervw 0:248d03543f5f 486 hc_c_size = ext_bits(csd, 63, 48);
davervw 0:248d03543f5f 487 int hc_read_bl_len = ext_bits(csd, 83, 80);
davervw 0:248d03543f5f 488 blocks = (hc_c_size+1)*1024;
davervw 0:248d03543f5f 489 #ifdef DEBUG
davervw 0:248d03543f5f 490 uint64_t hc_capacity = hc_c_size+1;
davervw 0:248d03543f5f 491 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);
davervw 0:248d03543f5f 492 #endif
davervw 0:248d03543f5f 493 break;
davervw 0:248d03543f5f 494 }
davervw 0:248d03543f5f 495
davervw 0:248d03543f5f 496 default:
davervw 0:248d03543f5f 497 fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
davervw 0:248d03543f5f 498 return 0;
davervw 0:248d03543f5f 499 };
davervw 0:248d03543f5f 500 return blocks;
davervw 0:248d03543f5f 501 }