Martin Sturm / Mbed 2 deprecated Lab3

Dependencies:   mbed

SDFileSystem/SDFileSystem.cpp@0:c546b51ecf0b, 2011-10-11 (annotated)

Committer:
XkLi
Date:
Tue Oct 11 01:24:18 2011 +0000
Revision:
0:c546b51ecf0b
v1.0

Who changed what in which revision?

UserRevisionLine numberNew contents of line
XkLi 0:c546b51ecf0b 1 /* mbed SDFileSystem Library, for providing file access to SD cards
XkLi 0:c546b51ecf0b 2 * Copyright (c) 2008-2010, sford
XkLi 0:c546b51ecf0b 3 *
XkLi 0:c546b51ecf0b 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
XkLi 0:c546b51ecf0b 5 * of this software and associated documentation files (the "Software"), to deal
XkLi 0:c546b51ecf0b 6 * in the Software without restriction, including without limitation the rights
XkLi 0:c546b51ecf0b 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
XkLi 0:c546b51ecf0b 8 * copies of the Software, and to permit persons to whom the Software is
XkLi 0:c546b51ecf0b 9 * furnished to do so, subject to the following conditions:
XkLi 0:c546b51ecf0b 10 *
XkLi 0:c546b51ecf0b 11 * The above copyright notice and this permission notice shall be included in
XkLi 0:c546b51ecf0b 12 * all copies or substantial portions of the Software.
XkLi 0:c546b51ecf0b 13 *
XkLi 0:c546b51ecf0b 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
XkLi 0:c546b51ecf0b 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
XkLi 0:c546b51ecf0b 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
XkLi 0:c546b51ecf0b 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
XkLi 0:c546b51ecf0b 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
XkLi 0:c546b51ecf0b 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
XkLi 0:c546b51ecf0b 20 * THE SOFTWARE.
XkLi 0:c546b51ecf0b 21 */
XkLi 0:c546b51ecf0b 22
XkLi 0:c546b51ecf0b 23 /* Introduction
XkLi 0:c546b51ecf0b 24 * ------------
XkLi 0:c546b51ecf0b 25 * SD and MMC cards support a number of interfaces, but common to them all
XkLi 0:c546b51ecf0b 26 * is one based on SPI. This is the one I'm implmenting because it means
XkLi 0:c546b51ecf0b 27 * it is much more portable even though not so performant, and we already
XkLi 0:c546b51ecf0b 28 * have the mbed SPI Interface!
XkLi 0:c546b51ecf0b 29 *
XkLi 0:c546b51ecf0b 30 * The main reference I'm using is Chapter 7, "SPI Mode" of:
XkLi 0:c546b51ecf0b 31 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
XkLi 0:c546b51ecf0b 32 *
XkLi 0:c546b51ecf0b 33 * SPI Startup
XkLi 0:c546b51ecf0b 34 * -----------
XkLi 0:c546b51ecf0b 35 * The SD card powers up in SD mode. The SPI interface mode is selected by
XkLi 0:c546b51ecf0b 36 * asserting CS low and sending the reset command (CMD0). The card will
XkLi 0:c546b51ecf0b 37 * respond with a (R1) response.
XkLi 0:c546b51ecf0b 38 *
XkLi 0:c546b51ecf0b 39 * CMD8 is optionally sent to determine the voltage range supported, and
XkLi 0:c546b51ecf0b 40 * indirectly determine whether it is a version 1.x SD/non-SD card or
XkLi 0:c546b51ecf0b 41 * version 2.x. I'll just ignore this for now.
XkLi 0:c546b51ecf0b 42 *
XkLi 0:c546b51ecf0b 43 * ACMD41 is repeatedly issued to initialise the card, until "in idle"
XkLi 0:c546b51ecf0b 44 * (bit 0) of the R1 response goes to '0', indicating it is initialised.
XkLi 0:c546b51ecf0b 45 *
XkLi 0:c546b51ecf0b 46 * You should also indicate whether the host supports High Capicity cards,
XkLi 0:c546b51ecf0b 47 * and check whether the card is high capacity - i'll also ignore this
XkLi 0:c546b51ecf0b 48 *
XkLi 0:c546b51ecf0b 49 * SPI Protocol
XkLi 0:c546b51ecf0b 50 * ------------
XkLi 0:c546b51ecf0b 51 * The SD SPI protocol is based on transactions made up of 8-bit words, with
XkLi 0:c546b51ecf0b 52 * the host starting every bus transaction by asserting the CS signal low. The
XkLi 0:c546b51ecf0b 53 * card always responds to commands, data blocks and errors.
XkLi 0:c546b51ecf0b 54 *
XkLi 0:c546b51ecf0b 55 * The protocol supports a CRC, but by default it is off (except for the
XkLi 0:c546b51ecf0b 56 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
XkLi 0:c546b51ecf0b 57 * I'll leave the CRC off I think!
XkLi 0:c546b51ecf0b 58 *
XkLi 0:c546b51ecf0b 59 * Standard capacity cards have variable data block sizes, whereas High
XkLi 0:c546b51ecf0b 60 * Capacity cards fix the size of data block to 512 bytes. I'll therefore
XkLi 0:c546b51ecf0b 61 * just always use the Standard Capacity cards with a block size of 512 bytes.
XkLi 0:c546b51ecf0b 62 * This is set with CMD16.
XkLi 0:c546b51ecf0b 63 *
XkLi 0:c546b51ecf0b 64 * You can read and write single blocks (CMD17, CMD25) or multiple blocks
XkLi 0:c546b51ecf0b 65 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
XkLi 0:c546b51ecf0b 66 * the card gets a read command, it responds with a response token, and then
XkLi 0:c546b51ecf0b 67 * a data token or an error.
XkLi 0:c546b51ecf0b 68 *
XkLi 0:c546b51ecf0b 69 * SPI Command Format
XkLi 0:c546b51ecf0b 70 * ------------------
XkLi 0:c546b51ecf0b 71 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
XkLi 0:c546b51ecf0b 72 *
XkLi 0:c546b51ecf0b 73 * +---------------+------------+------------+-----------+----------+--------------+
XkLi 0:c546b51ecf0b 74 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
XkLi 0:c546b51ecf0b 75 * +---------------+------------+------------+-----------+----------+--------------+
XkLi 0:c546b51ecf0b 76 *
XkLi 0:c546b51ecf0b 77 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
XkLi 0:c546b51ecf0b 78 *
XkLi 0:c546b51ecf0b 79 * All Application Specific commands shall be preceded with APP_CMD (CMD55).
XkLi 0:c546b51ecf0b 80 *
XkLi 0:c546b51ecf0b 81 * SPI Response Format
XkLi 0:c546b51ecf0b 82 * -------------------
XkLi 0:c546b51ecf0b 83 * The main response format (R1) is a status byte (normally zero). Key flags:
XkLi 0:c546b51ecf0b 84 * idle - 1 if the card is in an idle state/initialising
XkLi 0:c546b51ecf0b 85 * cmd - 1 if an illegal command code was detected
XkLi 0:c546b51ecf0b 86 *
XkLi 0:c546b51ecf0b 87 * +-------------------------------------------------+
XkLi 0:c546b51ecf0b 88 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
XkLi 0:c546b51ecf0b 89 * +-------------------------------------------------+
XkLi 0:c546b51ecf0b 90 *
XkLi 0:c546b51ecf0b 91 * R1b is the same, except it is followed by a busy signal (zeros) until
XkLi 0:c546b51ecf0b 92 * the first non-zero byte when it is ready again.
XkLi 0:c546b51ecf0b 93 *
XkLi 0:c546b51ecf0b 94 * Data Response Token
XkLi 0:c546b51ecf0b 95 * -------------------
XkLi 0:c546b51ecf0b 96 * Every data block written to the card is acknowledged by a byte
XkLi 0:c546b51ecf0b 97 * response token
XkLi 0:c546b51ecf0b 98 *
XkLi 0:c546b51ecf0b 99 * +----------------------+
XkLi 0:c546b51ecf0b 100 * | xxx | 0 | status | 1 |
XkLi 0:c546b51ecf0b 101 * +----------------------+
XkLi 0:c546b51ecf0b 102 * 010 - OK!
XkLi 0:c546b51ecf0b 103 * 101 - CRC Error
XkLi 0:c546b51ecf0b 104 * 110 - Write Error
XkLi 0:c546b51ecf0b 105 *
XkLi 0:c546b51ecf0b 106 * Single Block Read and Write
XkLi 0:c546b51ecf0b 107 * ---------------------------
XkLi 0:c546b51ecf0b 108 *
XkLi 0:c546b51ecf0b 109 * Block transfers have a byte header, followed by the data, followed
XkLi 0:c546b51ecf0b 110 * by a 16-bit CRC. In our case, the data will always be 512 bytes.
XkLi 0:c546b51ecf0b 111 *
XkLi 0:c546b51ecf0b 112 * +------+---------+---------+- - - -+---------+-----------+----------+
XkLi 0:c546b51ecf0b 113 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
XkLi 0:c546b51ecf0b 114 * +------+---------+---------+- - - -+---------+-----------+----------+
XkLi 0:c546b51ecf0b 115 */
XkLi 0:c546b51ecf0b 116
XkLi 0:c546b51ecf0b 117 #include "SDFileSystem.h"
XkLi 0:c546b51ecf0b 118
XkLi 0:c546b51ecf0b 119 #define SD_COMMAND_TIMEOUT 5000
XkLi 0:c546b51ecf0b 120
XkLi 0:c546b51ecf0b 121 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
XkLi 0:c546b51ecf0b 122 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
XkLi 0:c546b51ecf0b 123 _cs = 1;
XkLi 0:c546b51ecf0b 124 }
XkLi 0:c546b51ecf0b 125
XkLi 0:c546b51ecf0b 126 #define R1_IDLE_STATE (1 << 0)
XkLi 0:c546b51ecf0b 127 #define R1_ERASE_RESET (1 << 1)
XkLi 0:c546b51ecf0b 128 #define R1_ILLEGAL_COMMAND (1 << 2)
XkLi 0:c546b51ecf0b 129 #define R1_COM_CRC_ERROR (1 << 3)
XkLi 0:c546b51ecf0b 130 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
XkLi 0:c546b51ecf0b 131 #define R1_ADDRESS_ERROR (1 << 5)
XkLi 0:c546b51ecf0b 132 #define R1_PARAMETER_ERROR (1 << 6)
XkLi 0:c546b51ecf0b 133
XkLi 0:c546b51ecf0b 134 // Types
XkLi 0:c546b51ecf0b 135 // - v1.x Standard Capacity
XkLi 0:c546b51ecf0b 136 // - v2.x Standard Capacity
XkLi 0:c546b51ecf0b 137 // - v2.x High Capacity
XkLi 0:c546b51ecf0b 138 // - Not recognised as an SD Card
XkLi 0:c546b51ecf0b 139
XkLi 0:c546b51ecf0b 140 #define SDCARD_FAIL 0
XkLi 0:c546b51ecf0b 141 #define SDCARD_V1 1
XkLi 0:c546b51ecf0b 142 #define SDCARD_V2 2
XkLi 0:c546b51ecf0b 143 #define SDCARD_V2HC 3
XkLi 0:c546b51ecf0b 144
XkLi 0:c546b51ecf0b 145 int SDFileSystem::initialise_card() {
XkLi 0:c546b51ecf0b 146 // Set to 100kHz for initialisation, and clock card with cs = 1
XkLi 0:c546b51ecf0b 147 _spi.frequency(100000);
XkLi 0:c546b51ecf0b 148 _cs = 1;
XkLi 0:c546b51ecf0b 149 for(int i=0; i<16; i++) {
XkLi 0:c546b51ecf0b 150 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 151 }
XkLi 0:c546b51ecf0b 152
XkLi 0:c546b51ecf0b 153 // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
XkLi 0:c546b51ecf0b 154 if(_cmd(0, 0) != R1_IDLE_STATE) {
XkLi 0:c546b51ecf0b 155 fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
XkLi 0:c546b51ecf0b 156 return SDCARD_FAIL;
XkLi 0:c546b51ecf0b 157 }
XkLi 0:c546b51ecf0b 158
XkLi 0:c546b51ecf0b 159 // send CMD8 to determine whther it is ver 2.x
XkLi 0:c546b51ecf0b 160 int r = _cmd8();
XkLi 0:c546b51ecf0b 161 if(r == R1_IDLE_STATE) {
XkLi 0:c546b51ecf0b 162 return initialise_card_v2();
XkLi 0:c546b51ecf0b 163 } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
XkLi 0:c546b51ecf0b 164 return initialise_card_v1();
XkLi 0:c546b51ecf0b 165 } else {
XkLi 0:c546b51ecf0b 166 fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
XkLi 0:c546b51ecf0b 167 return SDCARD_FAIL;
XkLi 0:c546b51ecf0b 168 }
XkLi 0:c546b51ecf0b 169 }
XkLi 0:c546b51ecf0b 170
XkLi 0:c546b51ecf0b 171 int SDFileSystem::initialise_card_v1() {
XkLi 0:c546b51ecf0b 172 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
XkLi 0:c546b51ecf0b 173 _cmd(55, 0);
XkLi 0:c546b51ecf0b 174 if(_cmd(41, 0) == 0) {
XkLi 0:c546b51ecf0b 175 return SDCARD_V1;
XkLi 0:c546b51ecf0b 176 }
XkLi 0:c546b51ecf0b 177 }
XkLi 0:c546b51ecf0b 178
XkLi 0:c546b51ecf0b 179 fprintf(stderr, "Timeout waiting for v1.x card\n");
XkLi 0:c546b51ecf0b 180 return SDCARD_FAIL;
XkLi 0:c546b51ecf0b 181 }
XkLi 0:c546b51ecf0b 182
XkLi 0:c546b51ecf0b 183 int SDFileSystem::initialise_card_v2() {
XkLi 0:c546b51ecf0b 184
XkLi 0:c546b51ecf0b 185 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
XkLi 0:c546b51ecf0b 186 _cmd(55, 0);
XkLi 0:c546b51ecf0b 187 if(_cmd(41, 0) == 0) {
XkLi 0:c546b51ecf0b 188 _cmd58();
XkLi 0:c546b51ecf0b 189 return SDCARD_V2;
XkLi 0:c546b51ecf0b 190 }
XkLi 0:c546b51ecf0b 191 }
XkLi 0:c546b51ecf0b 192
XkLi 0:c546b51ecf0b 193 fprintf(stderr, "Timeout waiting for v2.x card\n");
XkLi 0:c546b51ecf0b 194 return SDCARD_FAIL;
XkLi 0:c546b51ecf0b 195 }
XkLi 0:c546b51ecf0b 196
XkLi 0:c546b51ecf0b 197 int SDFileSystem::disk_initialize() {
XkLi 0:c546b51ecf0b 198
XkLi 0:c546b51ecf0b 199 int i = initialise_card();
XkLi 0:c546b51ecf0b 200 // printf("init card = %d\n", i);
XkLi 0:c546b51ecf0b 201 // printf("OK\n");
XkLi 0:c546b51ecf0b 202
XkLi 0:c546b51ecf0b 203 _sectors = _sd_sectors();
XkLi 0:c546b51ecf0b 204
XkLi 0:c546b51ecf0b 205 // Set block length to 512 (CMD16)
XkLi 0:c546b51ecf0b 206 if(_cmd(16, 512) != 0) {
XkLi 0:c546b51ecf0b 207 fprintf(stderr, "Set 512-byte block timed out\n");
XkLi 0:c546b51ecf0b 208 return 1;
XkLi 0:c546b51ecf0b 209 }
XkLi 0:c546b51ecf0b 210
XkLi 0:c546b51ecf0b 211 _spi.frequency(1000000); // Set to 1MHz for data transfer
XkLi 0:c546b51ecf0b 212 return 0;
XkLi 0:c546b51ecf0b 213 }
XkLi 0:c546b51ecf0b 214
XkLi 0:c546b51ecf0b 215 int SDFileSystem::disk_write(const char *buffer, int block_number) {
XkLi 0:c546b51ecf0b 216 // set write address for single block (CMD24)
XkLi 0:c546b51ecf0b 217 if(_cmd(24, block_number * 512) != 0) {
XkLi 0:c546b51ecf0b 218 return 1;
XkLi 0:c546b51ecf0b 219 }
XkLi 0:c546b51ecf0b 220
XkLi 0:c546b51ecf0b 221 // send the data block
XkLi 0:c546b51ecf0b 222 _write(buffer, 512);
XkLi 0:c546b51ecf0b 223 return 0;
XkLi 0:c546b51ecf0b 224 }
XkLi 0:c546b51ecf0b 225
XkLi 0:c546b51ecf0b 226 int SDFileSystem::disk_read(char *buffer, int block_number) {
XkLi 0:c546b51ecf0b 227 // set read address for single block (CMD17)
XkLi 0:c546b51ecf0b 228 if(_cmd(17, block_number * 512) != 0) {
XkLi 0:c546b51ecf0b 229 return 1;
XkLi 0:c546b51ecf0b 230 }
XkLi 0:c546b51ecf0b 231
XkLi 0:c546b51ecf0b 232 // receive the data
XkLi 0:c546b51ecf0b 233 _read(buffer, 512);
XkLi 0:c546b51ecf0b 234 return 0;
XkLi 0:c546b51ecf0b 235 }
XkLi 0:c546b51ecf0b 236
XkLi 0:c546b51ecf0b 237 int SDFileSystem::disk_status() { return 0; }
XkLi 0:c546b51ecf0b 238 int SDFileSystem::disk_sync() { return 0; }
XkLi 0:c546b51ecf0b 239 int SDFileSystem::disk_sectors() { return _sectors; }
XkLi 0:c546b51ecf0b 240
XkLi 0:c546b51ecf0b 241 // PRIVATE FUNCTIONS
XkLi 0:c546b51ecf0b 242
XkLi 0:c546b51ecf0b 243 int SDFileSystem::_cmd(int cmd, int arg) {
XkLi 0:c546b51ecf0b 244 _cs = 0;
XkLi 0:c546b51ecf0b 245
XkLi 0:c546b51ecf0b 246 // send a command
XkLi 0:c546b51ecf0b 247 _spi.write(0x40 | cmd);
XkLi 0:c546b51ecf0b 248 _spi.write(arg >> 24);
XkLi 0:c546b51ecf0b 249 _spi.write(arg >> 16);
XkLi 0:c546b51ecf0b 250 _spi.write(arg >> 8);
XkLi 0:c546b51ecf0b 251 _spi.write(arg >> 0);
XkLi 0:c546b51ecf0b 252 _spi.write(0x95);
XkLi 0:c546b51ecf0b 253
XkLi 0:c546b51ecf0b 254 // wait for the repsonse (response[7] == 0)
XkLi 0:c546b51ecf0b 255 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
XkLi 0:c546b51ecf0b 256 int response = _spi.write(0xFF);
XkLi 0:c546b51ecf0b 257 if(!(response & 0x80)) {
XkLi 0:c546b51ecf0b 258 _cs = 1;
XkLi 0:c546b51ecf0b 259 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 260 return response;
XkLi 0:c546b51ecf0b 261 }
XkLi 0:c546b51ecf0b 262 }
XkLi 0:c546b51ecf0b 263 _cs = 1;
XkLi 0:c546b51ecf0b 264 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 265 return -1; // timeout
XkLi 0:c546b51ecf0b 266 }
XkLi 0:c546b51ecf0b 267 int SDFileSystem::_cmdx(int cmd, int arg) {
XkLi 0:c546b51ecf0b 268 _cs = 0;
XkLi 0:c546b51ecf0b 269
XkLi 0:c546b51ecf0b 270 // send a command
XkLi 0:c546b51ecf0b 271 _spi.write(0x40 | cmd);
XkLi 0:c546b51ecf0b 272 _spi.write(arg >> 24);
XkLi 0:c546b51ecf0b 273 _spi.write(arg >> 16);
XkLi 0:c546b51ecf0b 274 _spi.write(arg >> 8);
XkLi 0:c546b51ecf0b 275 _spi.write(arg >> 0);
XkLi 0:c546b51ecf0b 276 _spi.write(0x95);
XkLi 0:c546b51ecf0b 277
XkLi 0:c546b51ecf0b 278 // wait for the repsonse (response[7] == 0)
XkLi 0:c546b51ecf0b 279 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
XkLi 0:c546b51ecf0b 280 int response = _spi.write(0xFF);
XkLi 0:c546b51ecf0b 281 if(!(response & 0x80)) {
XkLi 0:c546b51ecf0b 282 return response;
XkLi 0:c546b51ecf0b 283 }
XkLi 0:c546b51ecf0b 284 }
XkLi 0:c546b51ecf0b 285 _cs = 1;
XkLi 0:c546b51ecf0b 286 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 287 return -1; // timeout
XkLi 0:c546b51ecf0b 288 }
XkLi 0:c546b51ecf0b 289
XkLi 0:c546b51ecf0b 290
XkLi 0:c546b51ecf0b 291 int SDFileSystem::_cmd58() {
XkLi 0:c546b51ecf0b 292 _cs = 0;
XkLi 0:c546b51ecf0b 293 int arg = 0;
XkLi 0:c546b51ecf0b 294
XkLi 0:c546b51ecf0b 295 // send a command
XkLi 0:c546b51ecf0b 296 _spi.write(0x40 | 58);
XkLi 0:c546b51ecf0b 297 _spi.write(arg >> 24);
XkLi 0:c546b51ecf0b 298 _spi.write(arg >> 16);
XkLi 0:c546b51ecf0b 299 _spi.write(arg >> 8);
XkLi 0:c546b51ecf0b 300 _spi.write(arg >> 0);
XkLi 0:c546b51ecf0b 301 _spi.write(0x95);
XkLi 0:c546b51ecf0b 302
XkLi 0:c546b51ecf0b 303 // wait for the repsonse (response[7] == 0)
XkLi 0:c546b51ecf0b 304 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
XkLi 0:c546b51ecf0b 305 int response = _spi.write(0xFF);
XkLi 0:c546b51ecf0b 306 if(!(response & 0x80)) {
XkLi 0:c546b51ecf0b 307 int ocr = _spi.write(0xFF) << 24;
XkLi 0:c546b51ecf0b 308 ocr |= _spi.write(0xFF) << 16;
XkLi 0:c546b51ecf0b 309 ocr |= _spi.write(0xFF) << 8;
XkLi 0:c546b51ecf0b 310 ocr |= _spi.write(0xFF) << 0;
XkLi 0:c546b51ecf0b 311 // printf("OCR = 0x%08X\n", ocr);
XkLi 0:c546b51ecf0b 312 _cs = 1;
XkLi 0:c546b51ecf0b 313 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 314 return response;
XkLi 0:c546b51ecf0b 315 }
XkLi 0:c546b51ecf0b 316 }
XkLi 0:c546b51ecf0b 317 _cs = 1;
XkLi 0:c546b51ecf0b 318 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 319 return -1; // timeout
XkLi 0:c546b51ecf0b 320 }
XkLi 0:c546b51ecf0b 321
XkLi 0:c546b51ecf0b 322 int SDFileSystem::_cmd8() {
XkLi 0:c546b51ecf0b 323 _cs = 0;
XkLi 0:c546b51ecf0b 324
XkLi 0:c546b51ecf0b 325 // send a command
XkLi 0:c546b51ecf0b 326 _spi.write(0x40 | 8); // CMD8
XkLi 0:c546b51ecf0b 327 _spi.write(0x00); // reserved
XkLi 0:c546b51ecf0b 328 _spi.write(0x00); // reserved
XkLi 0:c546b51ecf0b 329 _spi.write(0x01); // 3.3v
XkLi 0:c546b51ecf0b 330 _spi.write(0xAA); // check pattern
XkLi 0:c546b51ecf0b 331 _spi.write(0x87); // crc
XkLi 0:c546b51ecf0b 332
XkLi 0:c546b51ecf0b 333 // wait for the repsonse (response[7] == 0)
XkLi 0:c546b51ecf0b 334 for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
XkLi 0:c546b51ecf0b 335 char response[5];
XkLi 0:c546b51ecf0b 336 response[0] = _spi.write(0xFF);
XkLi 0:c546b51ecf0b 337 if(!(response[0] & 0x80)) {
XkLi 0:c546b51ecf0b 338 for(int j=1; j<5; j++) {
XkLi 0:c546b51ecf0b 339 response[i] = _spi.write(0xFF);
XkLi 0:c546b51ecf0b 340 }
XkLi 0:c546b51ecf0b 341 _cs = 1;
XkLi 0:c546b51ecf0b 342 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 343 return response[0];
XkLi 0:c546b51ecf0b 344 }
XkLi 0:c546b51ecf0b 345 }
XkLi 0:c546b51ecf0b 346 _cs = 1;
XkLi 0:c546b51ecf0b 347 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 348 return -1; // timeout
XkLi 0:c546b51ecf0b 349 }
XkLi 0:c546b51ecf0b 350
XkLi 0:c546b51ecf0b 351 int SDFileSystem::_read(char *buffer, int length) {
XkLi 0:c546b51ecf0b 352 _cs = 0;
XkLi 0:c546b51ecf0b 353
XkLi 0:c546b51ecf0b 354 // read until start byte (0xFF)
XkLi 0:c546b51ecf0b 355 while(_spi.write(0xFF) != 0xFE);
XkLi 0:c546b51ecf0b 356
XkLi 0:c546b51ecf0b 357 // read data
XkLi 0:c546b51ecf0b 358 for(int i=0; i<length; i++) {
XkLi 0:c546b51ecf0b 359 buffer[i] = _spi.write(0xFF);
XkLi 0:c546b51ecf0b 360 }
XkLi 0:c546b51ecf0b 361 _spi.write(0xFF); // checksum
XkLi 0:c546b51ecf0b 362 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 363
XkLi 0:c546b51ecf0b 364 _cs = 1;
XkLi 0:c546b51ecf0b 365 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 366 return 0;
XkLi 0:c546b51ecf0b 367 }
XkLi 0:c546b51ecf0b 368
XkLi 0:c546b51ecf0b 369 int SDFileSystem::_write(const char *buffer, int length) {
XkLi 0:c546b51ecf0b 370 _cs = 0;
XkLi 0:c546b51ecf0b 371
XkLi 0:c546b51ecf0b 372 // indicate start of block
XkLi 0:c546b51ecf0b 373 _spi.write(0xFE);
XkLi 0:c546b51ecf0b 374
XkLi 0:c546b51ecf0b 375 // write the data
XkLi 0:c546b51ecf0b 376 for(int i=0; i<length; i++) {
XkLi 0:c546b51ecf0b 377 _spi.write(buffer[i]);
XkLi 0:c546b51ecf0b 378 }
XkLi 0:c546b51ecf0b 379
XkLi 0:c546b51ecf0b 380 // write the checksum
XkLi 0:c546b51ecf0b 381 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 382 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 383
XkLi 0:c546b51ecf0b 384 // check the repsonse token
XkLi 0:c546b51ecf0b 385 if((_spi.write(0xFF) & 0x1F) != 0x05) {
XkLi 0:c546b51ecf0b 386 _cs = 1;
XkLi 0:c546b51ecf0b 387 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 388 return 1;
XkLi 0:c546b51ecf0b 389 }
XkLi 0:c546b51ecf0b 390
XkLi 0:c546b51ecf0b 391 // wait for write to finish
XkLi 0:c546b51ecf0b 392 while(_spi.write(0xFF) == 0);
XkLi 0:c546b51ecf0b 393
XkLi 0:c546b51ecf0b 394 _cs = 1;
XkLi 0:c546b51ecf0b 395 _spi.write(0xFF);
XkLi 0:c546b51ecf0b 396 return 0;
XkLi 0:c546b51ecf0b 397 }
XkLi 0:c546b51ecf0b 398
XkLi 0:c546b51ecf0b 399 static int ext_bits(char *data, int msb, int lsb) {
XkLi 0:c546b51ecf0b 400 int bits = 0;
XkLi 0:c546b51ecf0b 401 int size = 1 + msb - lsb;
XkLi 0:c546b51ecf0b 402 for(int i=0; i<size; i++) {
XkLi 0:c546b51ecf0b 403 int position = lsb + i;
XkLi 0:c546b51ecf0b 404 int byte = 15 - (position >> 3);
XkLi 0:c546b51ecf0b 405 int bit = position & 0x7;
XkLi 0:c546b51ecf0b 406 int value = (data[byte] >> bit) & 1;
XkLi 0:c546b51ecf0b 407 bits |= value << i;
XkLi 0:c546b51ecf0b 408 }
XkLi 0:c546b51ecf0b 409 return bits;
XkLi 0:c546b51ecf0b 410 }
XkLi 0:c546b51ecf0b 411
XkLi 0:c546b51ecf0b 412 int SDFileSystem::_sd_sectors() {
XkLi 0:c546b51ecf0b 413
XkLi 0:c546b51ecf0b 414 // CMD9, Response R2 (R1 byte + 16-byte block read)
XkLi 0:c546b51ecf0b 415 if(_cmdx(9, 0) != 0) {
XkLi 0:c546b51ecf0b 416 fprintf(stderr, "Didn't get a response from the disk\n");
XkLi 0:c546b51ecf0b 417 return 0;
XkLi 0:c546b51ecf0b 418 }
XkLi 0:c546b51ecf0b 419
XkLi 0:c546b51ecf0b 420 char csd[16];
XkLi 0:c546b51ecf0b 421 if(_read(csd, 16) != 0) {
XkLi 0:c546b51ecf0b 422 fprintf(stderr, "Couldn't read csd response from disk\n");
XkLi 0:c546b51ecf0b 423 return 0;
XkLi 0:c546b51ecf0b 424 }
XkLi 0:c546b51ecf0b 425
XkLi 0:c546b51ecf0b 426 // csd_structure : csd[127:126]
XkLi 0:c546b51ecf0b 427 // c_size : csd[73:62]
XkLi 0:c546b51ecf0b 428 // c_size_mult : csd[49:47]
XkLi 0:c546b51ecf0b 429 // read_bl_len : csd[83:80] - the *maximum* read block length
XkLi 0:c546b51ecf0b 430
XkLi 0:c546b51ecf0b 431 int csd_structure = ext_bits(csd, 127, 126);
XkLi 0:c546b51ecf0b 432 int c_size = ext_bits(csd, 73, 62);
XkLi 0:c546b51ecf0b 433 int c_size_mult = ext_bits(csd, 49, 47);
XkLi 0:c546b51ecf0b 434 int read_bl_len = ext_bits(csd, 83, 80);
XkLi 0:c546b51ecf0b 435
XkLi 0:c546b51ecf0b 436 // printf("CSD_STRUCT = %d\n", csd_structure);
XkLi 0:c546b51ecf0b 437
XkLi 0:c546b51ecf0b 438 if(csd_structure != 0) {
XkLi 0:c546b51ecf0b 439 fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
XkLi 0:c546b51ecf0b 440 return 0;
XkLi 0:c546b51ecf0b 441 }
XkLi 0:c546b51ecf0b 442
XkLi 0:c546b51ecf0b 443 // memory capacity = BLOCKNR * BLOCK_LEN
XkLi 0:c546b51ecf0b 444 // where
XkLi 0:c546b51ecf0b 445 // BLOCKNR = (C_SIZE+1) * MULT
XkLi 0:c546b51ecf0b 446 // MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
XkLi 0:c546b51ecf0b 447 // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
XkLi 0:c546b51ecf0b 448
XkLi 0:c546b51ecf0b 449 int block_len = 1 << read_bl_len;
XkLi 0:c546b51ecf0b 450 int mult = 1 << (c_size_mult + 2);
XkLi 0:c546b51ecf0b 451 int blocknr = (c_size + 1) * mult;
XkLi 0:c546b51ecf0b 452 int capacity = blocknr * block_len;
XkLi 0:c546b51ecf0b 453
XkLi 0:c546b51ecf0b 454 int blocks = capacity / 512;
XkLi 0:c546b51ecf0b 455
XkLi 0:c546b51ecf0b 456 return blocks;
XkLi 0:c546b51ecf0b 457 }