ECE 2035 TA / SDFileSystem

SDFileSystem Library

Dependents:   ECE2035_SUM17_Project

SDFileSystem.cpp@0:71be9322f4eb, 2017-07-14 (annotated)

Committer:
kennyainny
Date:
Fri Jul 14 21:42:13 2017 +0000
Revision:
0:71be9322f4eb
no changes

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kennyainny 0:71be9322f4eb 1 /* mbed Microcontroller Library
kennyainny 0:71be9322f4eb 2 * Copyright (c) 2006-2012 ARM Limited
kennyainny 0:71be9322f4eb 3 *
kennyainny 0:71be9322f4eb 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
kennyainny 0:71be9322f4eb 5 * of this software and associated documentation files (the "Software"), to deal
kennyainny 0:71be9322f4eb 6 * in the Software without restriction, including without limitation the rights
kennyainny 0:71be9322f4eb 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
kennyainny 0:71be9322f4eb 8 * copies of the Software, and to permit persons to whom the Software is
kennyainny 0:71be9322f4eb 9 * furnished to do so, subject to the following conditions:
kennyainny 0:71be9322f4eb 10 *
kennyainny 0:71be9322f4eb 11 * The above copyright notice and this permission notice shall be included in
kennyainny 0:71be9322f4eb 12 * all copies or substantial portions of the Software.
kennyainny 0:71be9322f4eb 13 *
kennyainny 0:71be9322f4eb 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
kennyainny 0:71be9322f4eb 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
kennyainny 0:71be9322f4eb 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
kennyainny 0:71be9322f4eb 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
kennyainny 0:71be9322f4eb 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
kennyainny 0:71be9322f4eb 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
kennyainny 0:71be9322f4eb 20 * SOFTWARE.
kennyainny 0:71be9322f4eb 21 */
kennyainny 0:71be9322f4eb 22 /* Introduction
kennyainny 0:71be9322f4eb 23 * ------------
kennyainny 0:71be9322f4eb 24 * SD and MMC cards support a number of interfaces, but common to them all
kennyainny 0:71be9322f4eb 25 * is one based on SPI. This is the one I'm implmenting because it means
kennyainny 0:71be9322f4eb 26 * it is much more portable even though not so performant, and we already
kennyainny 0:71be9322f4eb 27 * have the mbed SPI Interface!
kennyainny 0:71be9322f4eb 28 *
kennyainny 0:71be9322f4eb 29 * The main reference I'm using is Chapter 7, "SPI Mode" of:
kennyainny 0:71be9322f4eb 30 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
kennyainny 0:71be9322f4eb 31 *
kennyainny 0:71be9322f4eb 32 * SPI Startup
kennyainny 0:71be9322f4eb 33 * -----------
kennyainny 0:71be9322f4eb 34 * The SD card powers up in SD mode. The SPI interface mode is selected by
kennyainny 0:71be9322f4eb 35 * asserting CS low and sending the reset command (CMD0). The card will
kennyainny 0:71be9322f4eb 36 * respond with a (R1) response.
kennyainny 0:71be9322f4eb 37 *
kennyainny 0:71be9322f4eb 38 * CMD8 is optionally sent to determine the voltage range supported, and
kennyainny 0:71be9322f4eb 39 * indirectly determine whether it is a version 1.x SD/non-SD card or
kennyainny 0:71be9322f4eb 40 * version 2.x. I'll just ignore this for now.
kennyainny 0:71be9322f4eb 41 *
kennyainny 0:71be9322f4eb 42 * ACMD41 is repeatedly issued to initialise the card, until "in idle"
kennyainny 0:71be9322f4eb 43 * (bit 0) of the R1 response goes to '0', indicating it is initialised.
kennyainny 0:71be9322f4eb 44 *
kennyainny 0:71be9322f4eb 45 * You should also indicate whether the host supports High Capicity cards,
kennyainny 0:71be9322f4eb 46 * and check whether the card is high capacity - i'll also ignore this
kennyainny 0:71be9322f4eb 47 *
kennyainny 0:71be9322f4eb 48 * SPI Protocol
kennyainny 0:71be9322f4eb 49 * ------------
kennyainny 0:71be9322f4eb 50 * The SD SPI protocol is based on transactions made up of 8-bit words, with
kennyainny 0:71be9322f4eb 51 * the host starting every bus transaction by asserting the CS signal low. The
kennyainny 0:71be9322f4eb 52 * card always responds to commands, data blocks and errors.
kennyainny 0:71be9322f4eb 53 *
kennyainny 0:71be9322f4eb 54 * The protocol supports a CRC, but by default it is off (except for the
kennyainny 0:71be9322f4eb 55 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
kennyainny 0:71be9322f4eb 56 * I'll leave the CRC off I think!
kennyainny 0:71be9322f4eb 57 *
kennyainny 0:71be9322f4eb 58 * Standard capacity cards have variable data block sizes, whereas High
kennyainny 0:71be9322f4eb 59 * Capacity cards fix the size of data block to 512 bytes. I'll therefore
kennyainny 0:71be9322f4eb 60 * just always use the Standard Capacity cards with a block size of 512 bytes.
kennyainny 0:71be9322f4eb 61 * This is set with CMD16.
kennyainny 0:71be9322f4eb 62 *
kennyainny 0:71be9322f4eb 63 * You can read and write single blocks (CMD17, CMD25) or multiple blocks
kennyainny 0:71be9322f4eb 64 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
kennyainny 0:71be9322f4eb 65 * the card gets a read command, it responds with a response token, and then
kennyainny 0:71be9322f4eb 66 * a data token or an error.
kennyainny 0:71be9322f4eb 67 *
kennyainny 0:71be9322f4eb 68 * SPI Command Format
kennyainny 0:71be9322f4eb 69 * ------------------
kennyainny 0:71be9322f4eb 70 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
kennyainny 0:71be9322f4eb 71 *
kennyainny 0:71be9322f4eb 72 * +---------------+------------+------------+-----------+----------+--------------+
kennyainny 0:71be9322f4eb 73 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
kennyainny 0:71be9322f4eb 74 * +---------------+------------+------------+-----------+----------+--------------+
kennyainny 0:71be9322f4eb 75 *
kennyainny 0:71be9322f4eb 76 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
kennyainny 0:71be9322f4eb 77 *
kennyainny 0:71be9322f4eb 78 * All Application Specific commands shall be preceded with APP_CMD (CMD55).
kennyainny 0:71be9322f4eb 79 *
kennyainny 0:71be9322f4eb 80 * SPI Response Format
kennyainny 0:71be9322f4eb 81 * -------------------
kennyainny 0:71be9322f4eb 82 * The main response format (R1) is a status byte (normally zero). Key flags:
kennyainny 0:71be9322f4eb 83 * idle - 1 if the card is in an idle state/initialising
kennyainny 0:71be9322f4eb 84 * cmd - 1 if an illegal command code was detected
kennyainny 0:71be9322f4eb 85 *
kennyainny 0:71be9322f4eb 86 * +-------------------------------------------------+
kennyainny 0:71be9322f4eb 87 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
kennyainny 0:71be9322f4eb 88 * +-------------------------------------------------+
kennyainny 0:71be9322f4eb 89 *
kennyainny 0:71be9322f4eb 90 * R1b is the same, except it is followed by a busy signal (zeros) until
kennyainny 0:71be9322f4eb 91 * the first non-zero byte when it is ready again.
kennyainny 0:71be9322f4eb 92 *
kennyainny 0:71be9322f4eb 93 * Data Response Token
kennyainny 0:71be9322f4eb 94 * -------------------
kennyainny 0:71be9322f4eb 95 * Every data block written to the card is acknowledged by a byte
kennyainny 0:71be9322f4eb 96 * response token
kennyainny 0:71be9322f4eb 97 *
kennyainny 0:71be9322f4eb 98 * +----------------------+
kennyainny 0:71be9322f4eb 99 * | xxx | 0 | status | 1 |
kennyainny 0:71be9322f4eb 100 * +----------------------+
kennyainny 0:71be9322f4eb 101 * 010 - OK!
kennyainny 0:71be9322f4eb 102 * 101 - CRC Error
kennyainny 0:71be9322f4eb 103 * 110 - Write Error
kennyainny 0:71be9322f4eb 104 *
kennyainny 0:71be9322f4eb 105 * Single Block Read and Write
kennyainny 0:71be9322f4eb 106 * ---------------------------
kennyainny 0:71be9322f4eb 107 *
kennyainny 0:71be9322f4eb 108 * Block transfers have a byte header, followed by the data, followed
kennyainny 0:71be9322f4eb 109 * by a 16-bit CRC. In our case, the data will always be 512 bytes.
kennyainny 0:71be9322f4eb 110 *
kennyainny 0:71be9322f4eb 111 * +------+---------+---------+- - - -+---------+-----------+----------+
kennyainny 0:71be9322f4eb 112 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
kennyainny 0:71be9322f4eb 113 * +------+---------+---------+- - - -+---------+-----------+----------+
kennyainny 0:71be9322f4eb 114 */
kennyainny 0:71be9322f4eb 115 #include "SDFileSystem.h"
kennyainny 0:71be9322f4eb 116 #include "mbed_debug.h"
kennyainny 0:71be9322f4eb 117
kennyainny 0:71be9322f4eb 118 #define SD_COMMAND_TIMEOUT 5000
kennyainny 0:71be9322f4eb 119
kennyainny 0:71be9322f4eb 120 #define SD_DBG 0
kennyainny 0:71be9322f4eb 121
kennyainny 0:71be9322f4eb 122 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
kennyainny 0:71be9322f4eb 123 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
kennyainny 0:71be9322f4eb 124 _cs = 1;
kennyainny 0:71be9322f4eb 125 }
kennyainny 0:71be9322f4eb 126
kennyainny 0:71be9322f4eb 127 #define R1_IDLE_STATE (1 << 0)
kennyainny 0:71be9322f4eb 128 #define R1_ERASE_RESET (1 << 1)
kennyainny 0:71be9322f4eb 129 #define R1_ILLEGAL_COMMAND (1 << 2)
kennyainny 0:71be9322f4eb 130 #define R1_COM_CRC_ERROR (1 << 3)
kennyainny 0:71be9322f4eb 131 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
kennyainny 0:71be9322f4eb 132 #define R1_ADDRESS_ERROR (1 << 5)
kennyainny 0:71be9322f4eb 133 #define R1_PARAMETER_ERROR (1 << 6)
kennyainny 0:71be9322f4eb 134
kennyainny 0:71be9322f4eb 135 // Types
kennyainny 0:71be9322f4eb 136 // - v1.x Standard Capacity
kennyainny 0:71be9322f4eb 137 // - v2.x Standard Capacity
kennyainny 0:71be9322f4eb 138 // - v2.x High Capacity
kennyainny 0:71be9322f4eb 139 // - Not recognised as an SD Card
kennyainny 0:71be9322f4eb 140 #define SDCARD_FAIL 0
kennyainny 0:71be9322f4eb 141 #define SDCARD_V1 1
kennyainny 0:71be9322f4eb 142 #define SDCARD_V2 2
kennyainny 0:71be9322f4eb 143 #define SDCARD_V2HC 3
kennyainny 0:71be9322f4eb 144
kennyainny 0:71be9322f4eb 145 int SDFileSystem::initialise_card() {
kennyainny 0:71be9322f4eb 146 // Set to 100kHz for initialisation, and clock card with cs = 1
kennyainny 0:71be9322f4eb 147 _spi.frequency(100000);
kennyainny 0:71be9322f4eb 148 _cs = 1;
kennyainny 0:71be9322f4eb 149 for (int i = 0; i < 16; i++) {
kennyainny 0:71be9322f4eb 150 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 151 }
kennyainny 0:71be9322f4eb 152
kennyainny 0:71be9322f4eb 153 // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
kennyainny 0:71be9322f4eb 154 if (_cmd(0, 0) != R1_IDLE_STATE) {
kennyainny 0:71be9322f4eb 155 debug("No disk, or could not put SD card in to SPI idle state\n");
kennyainny 0:71be9322f4eb 156 return SDCARD_FAIL;
kennyainny 0:71be9322f4eb 157 }
kennyainny 0:71be9322f4eb 158
kennyainny 0:71be9322f4eb 159 // send CMD8 to determine whther it is ver 2.x
kennyainny 0:71be9322f4eb 160 int r = _cmd8();
kennyainny 0:71be9322f4eb 161 if (r == R1_IDLE_STATE) {
kennyainny 0:71be9322f4eb 162 return initialise_card_v2();
kennyainny 0:71be9322f4eb 163 } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
kennyainny 0:71be9322f4eb 164 return initialise_card_v1();
kennyainny 0:71be9322f4eb 165 } else {
kennyainny 0:71be9322f4eb 166 debug("Not in idle state after sending CMD8 (not an SD card?)\n");
kennyainny 0:71be9322f4eb 167 return SDCARD_FAIL;
kennyainny 0:71be9322f4eb 168 }
kennyainny 0:71be9322f4eb 169 }
kennyainny 0:71be9322f4eb 170
kennyainny 0:71be9322f4eb 171 int SDFileSystem::initialise_card_v1() {
kennyainny 0:71be9322f4eb 172 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
kennyainny 0:71be9322f4eb 173 _cmd(55, 0);
kennyainny 0:71be9322f4eb 174 if (_cmd(41, 0) == 0) {
kennyainny 0:71be9322f4eb 175 cdv = 512;
kennyainny 0:71be9322f4eb 176 debug_if(SD_DBG, "\n\rInit: SEDCARD_V1\n\r");
kennyainny 0:71be9322f4eb 177 return SDCARD_V1;
kennyainny 0:71be9322f4eb 178 }
kennyainny 0:71be9322f4eb 179 }
kennyainny 0:71be9322f4eb 180
kennyainny 0:71be9322f4eb 181 debug("Timeout waiting for v1.x card\n");
kennyainny 0:71be9322f4eb 182 return SDCARD_FAIL;
kennyainny 0:71be9322f4eb 183 }
kennyainny 0:71be9322f4eb 184
kennyainny 0:71be9322f4eb 185 int SDFileSystem::initialise_card_v2() {
kennyainny 0:71be9322f4eb 186 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
kennyainny 0:71be9322f4eb 187 wait_ms(50);
kennyainny 0:71be9322f4eb 188 _cmd58();
kennyainny 0:71be9322f4eb 189 _cmd(55, 0);
kennyainny 0:71be9322f4eb 190 if (_cmd(41, 0x40000000) == 0) {
kennyainny 0:71be9322f4eb 191 _cmd58();
kennyainny 0:71be9322f4eb 192 debug_if(SD_DBG, "\n\rInit: SDCARD_V2\n\r");
kennyainny 0:71be9322f4eb 193 cdv = 1;
kennyainny 0:71be9322f4eb 194 return SDCARD_V2;
kennyainny 0:71be9322f4eb 195 }
kennyainny 0:71be9322f4eb 196 }
kennyainny 0:71be9322f4eb 197
kennyainny 0:71be9322f4eb 198 debug("Timeout waiting for v2.x card\n");
kennyainny 0:71be9322f4eb 199 return SDCARD_FAIL;
kennyainny 0:71be9322f4eb 200 }
kennyainny 0:71be9322f4eb 201
kennyainny 0:71be9322f4eb 202 int SDFileSystem::disk_initialize() {
kennyainny 0:71be9322f4eb 203 int i = initialise_card();
kennyainny 0:71be9322f4eb 204 debug_if(SD_DBG, "init card = %d\n", i);
kennyainny 0:71be9322f4eb 205 _sectors = _sd_sectors();
kennyainny 0:71be9322f4eb 206
kennyainny 0:71be9322f4eb 207 // Set block length to 512 (CMD16)
kennyainny 0:71be9322f4eb 208 if (_cmd(16, 512) != 0) {
kennyainny 0:71be9322f4eb 209 debug("Set 512-byte block timed out\n");
kennyainny 0:71be9322f4eb 210 return 1;
kennyainny 0:71be9322f4eb 211 }
kennyainny 0:71be9322f4eb 212
kennyainny 0:71be9322f4eb 213 _spi.frequency(1000000); // Set to 1MHz for data transfer
kennyainny 0:71be9322f4eb 214 return 0;
kennyainny 0:71be9322f4eb 215 }
kennyainny 0:71be9322f4eb 216
kennyainny 0:71be9322f4eb 217 int SDFileSystem::disk_write(const uint8_t *buffer, uint64_t block_number) {
kennyainny 0:71be9322f4eb 218 // set write address for single block (CMD24)
kennyainny 0:71be9322f4eb 219 if (_cmd(24, block_number * cdv) != 0) {
kennyainny 0:71be9322f4eb 220 return 1;
kennyainny 0:71be9322f4eb 221 }
kennyainny 0:71be9322f4eb 222
kennyainny 0:71be9322f4eb 223 // send the data block
kennyainny 0:71be9322f4eb 224 _write(buffer, 512);
kennyainny 0:71be9322f4eb 225 return 0;
kennyainny 0:71be9322f4eb 226 }
kennyainny 0:71be9322f4eb 227
kennyainny 0:71be9322f4eb 228 int SDFileSystem::disk_read(uint8_t *buffer, uint64_t block_number) {
kennyainny 0:71be9322f4eb 229 // set read address for single block (CMD17)
kennyainny 0:71be9322f4eb 230 if (_cmd(17, block_number * cdv) != 0) {
kennyainny 0:71be9322f4eb 231 return 1;
kennyainny 0:71be9322f4eb 232 }
kennyainny 0:71be9322f4eb 233
kennyainny 0:71be9322f4eb 234 // receive the data
kennyainny 0:71be9322f4eb 235 _read(buffer, 512);
kennyainny 0:71be9322f4eb 236 return 0;
kennyainny 0:71be9322f4eb 237 }
kennyainny 0:71be9322f4eb 238
kennyainny 0:71be9322f4eb 239 int SDFileSystem::disk_status() { return 0; }
kennyainny 0:71be9322f4eb 240 int SDFileSystem::disk_sync() { return 0; }
kennyainny 0:71be9322f4eb 241 uint64_t SDFileSystem::disk_sectors() { return _sectors; }
kennyainny 0:71be9322f4eb 242
kennyainny 0:71be9322f4eb 243
kennyainny 0:71be9322f4eb 244 // PRIVATE FUNCTIONS
kennyainny 0:71be9322f4eb 245 int SDFileSystem::_cmd(int cmd, int arg) {
kennyainny 0:71be9322f4eb 246 _cs = 0;
kennyainny 0:71be9322f4eb 247
kennyainny 0:71be9322f4eb 248 // send a command
kennyainny 0:71be9322f4eb 249 _spi.write(0x40 | cmd);
kennyainny 0:71be9322f4eb 250 _spi.write(arg >> 24);
kennyainny 0:71be9322f4eb 251 _spi.write(arg >> 16);
kennyainny 0:71be9322f4eb 252 _spi.write(arg >> 8);
kennyainny 0:71be9322f4eb 253 _spi.write(arg >> 0);
kennyainny 0:71be9322f4eb 254 _spi.write(0x95);
kennyainny 0:71be9322f4eb 255
kennyainny 0:71be9322f4eb 256 // wait for the repsonse (response[7] == 0)
kennyainny 0:71be9322f4eb 257 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
kennyainny 0:71be9322f4eb 258 int response = _spi.write(0xFF);
kennyainny 0:71be9322f4eb 259 if (!(response & 0x80)) {
kennyainny 0:71be9322f4eb 260 _cs = 1;
kennyainny 0:71be9322f4eb 261 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 262 return response;
kennyainny 0:71be9322f4eb 263 }
kennyainny 0:71be9322f4eb 264 }
kennyainny 0:71be9322f4eb 265 _cs = 1;
kennyainny 0:71be9322f4eb 266 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 267 return -1; // timeout
kennyainny 0:71be9322f4eb 268 }
kennyainny 0:71be9322f4eb 269 int SDFileSystem::_cmdx(int cmd, int arg) {
kennyainny 0:71be9322f4eb 270 _cs = 0;
kennyainny 0:71be9322f4eb 271
kennyainny 0:71be9322f4eb 272 // send a command
kennyainny 0:71be9322f4eb 273 _spi.write(0x40 | cmd);
kennyainny 0:71be9322f4eb 274 _spi.write(arg >> 24);
kennyainny 0:71be9322f4eb 275 _spi.write(arg >> 16);
kennyainny 0:71be9322f4eb 276 _spi.write(arg >> 8);
kennyainny 0:71be9322f4eb 277 _spi.write(arg >> 0);
kennyainny 0:71be9322f4eb 278 _spi.write(0x95);
kennyainny 0:71be9322f4eb 279
kennyainny 0:71be9322f4eb 280 // wait for the repsonse (response[7] == 0)
kennyainny 0:71be9322f4eb 281 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
kennyainny 0:71be9322f4eb 282 int response = _spi.write(0xFF);
kennyainny 0:71be9322f4eb 283 if (!(response & 0x80)) {
kennyainny 0:71be9322f4eb 284 return response;
kennyainny 0:71be9322f4eb 285 }
kennyainny 0:71be9322f4eb 286 }
kennyainny 0:71be9322f4eb 287 _cs = 1;
kennyainny 0:71be9322f4eb 288 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 289 return -1; // timeout
kennyainny 0:71be9322f4eb 290 }
kennyainny 0:71be9322f4eb 291
kennyainny 0:71be9322f4eb 292
kennyainny 0:71be9322f4eb 293 int SDFileSystem::_cmd58() {
kennyainny 0:71be9322f4eb 294 _cs = 0;
kennyainny 0:71be9322f4eb 295 int arg = 0;
kennyainny 0:71be9322f4eb 296
kennyainny 0:71be9322f4eb 297 // send a command
kennyainny 0:71be9322f4eb 298 _spi.write(0x40 | 58);
kennyainny 0:71be9322f4eb 299 _spi.write(arg >> 24);
kennyainny 0:71be9322f4eb 300 _spi.write(arg >> 16);
kennyainny 0:71be9322f4eb 301 _spi.write(arg >> 8);
kennyainny 0:71be9322f4eb 302 _spi.write(arg >> 0);
kennyainny 0:71be9322f4eb 303 _spi.write(0x95);
kennyainny 0:71be9322f4eb 304
kennyainny 0:71be9322f4eb 305 // wait for the repsonse (response[7] == 0)
kennyainny 0:71be9322f4eb 306 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
kennyainny 0:71be9322f4eb 307 int response = _spi.write(0xFF);
kennyainny 0:71be9322f4eb 308 if (!(response & 0x80)) {
kennyainny 0:71be9322f4eb 309 int ocr = _spi.write(0xFF) << 24;
kennyainny 0:71be9322f4eb 310 ocr |= _spi.write(0xFF) << 16;
kennyainny 0:71be9322f4eb 311 ocr |= _spi.write(0xFF) << 8;
kennyainny 0:71be9322f4eb 312 ocr |= _spi.write(0xFF) << 0;
kennyainny 0:71be9322f4eb 313 _cs = 1;
kennyainny 0:71be9322f4eb 314 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 315 return response;
kennyainny 0:71be9322f4eb 316 }
kennyainny 0:71be9322f4eb 317 }
kennyainny 0:71be9322f4eb 318 _cs = 1;
kennyainny 0:71be9322f4eb 319 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 320 return -1; // timeout
kennyainny 0:71be9322f4eb 321 }
kennyainny 0:71be9322f4eb 322
kennyainny 0:71be9322f4eb 323 int SDFileSystem::_cmd8() {
kennyainny 0:71be9322f4eb 324 _cs = 0;
kennyainny 0:71be9322f4eb 325
kennyainny 0:71be9322f4eb 326 // send a command
kennyainny 0:71be9322f4eb 327 _spi.write(0x40 | 8); // CMD8
kennyainny 0:71be9322f4eb 328 _spi.write(0x00); // reserved
kennyainny 0:71be9322f4eb 329 _spi.write(0x00); // reserved
kennyainny 0:71be9322f4eb 330 _spi.write(0x01); // 3.3v
kennyainny 0:71be9322f4eb 331 _spi.write(0xAA); // check pattern
kennyainny 0:71be9322f4eb 332 _spi.write(0x87); // crc
kennyainny 0:71be9322f4eb 333
kennyainny 0:71be9322f4eb 334 // wait for the repsonse (response[7] == 0)
kennyainny 0:71be9322f4eb 335 for (int i = 0; i < SD_COMMAND_TIMEOUT * 1000; i++) {
kennyainny 0:71be9322f4eb 336 char response[5];
kennyainny 0:71be9322f4eb 337 response[0] = _spi.write(0xFF);
kennyainny 0:71be9322f4eb 338 if (!(response[0] & 0x80)) {
kennyainny 0:71be9322f4eb 339 for (int j = 1; j < 5; j++) {
kennyainny 0:71be9322f4eb 340 response[i] = _spi.write(0xFF);
kennyainny 0:71be9322f4eb 341 }
kennyainny 0:71be9322f4eb 342 _cs = 1;
kennyainny 0:71be9322f4eb 343 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 344 return response[0];
kennyainny 0:71be9322f4eb 345 }
kennyainny 0:71be9322f4eb 346 }
kennyainny 0:71be9322f4eb 347 _cs = 1;
kennyainny 0:71be9322f4eb 348 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 349 return -1; // timeout
kennyainny 0:71be9322f4eb 350 }
kennyainny 0:71be9322f4eb 351
kennyainny 0:71be9322f4eb 352 int SDFileSystem::_read(uint8_t *buffer, uint32_t length) {
kennyainny 0:71be9322f4eb 353 _cs = 0;
kennyainny 0:71be9322f4eb 354
kennyainny 0:71be9322f4eb 355 // read until start byte (0xFF)
kennyainny 0:71be9322f4eb 356 while (_spi.write(0xFF) != 0xFE);
kennyainny 0:71be9322f4eb 357
kennyainny 0:71be9322f4eb 358 // read data
kennyainny 0:71be9322f4eb 359 for (int i = 0; i < length; i++) {
kennyainny 0:71be9322f4eb 360 buffer[i] = _spi.write(0xFF);
kennyainny 0:71be9322f4eb 361 }
kennyainny 0:71be9322f4eb 362 _spi.write(0xFF); // checksum
kennyainny 0:71be9322f4eb 363 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 364
kennyainny 0:71be9322f4eb 365 _cs = 1;
kennyainny 0:71be9322f4eb 366 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 367 return 0;
kennyainny 0:71be9322f4eb 368 }
kennyainny 0:71be9322f4eb 369
kennyainny 0:71be9322f4eb 370 int SDFileSystem::_write(const uint8_t*buffer, uint32_t length) {
kennyainny 0:71be9322f4eb 371 _cs = 0;
kennyainny 0:71be9322f4eb 372
kennyainny 0:71be9322f4eb 373 // indicate start of block
kennyainny 0:71be9322f4eb 374 _spi.write(0xFE);
kennyainny 0:71be9322f4eb 375
kennyainny 0:71be9322f4eb 376 // write the data
kennyainny 0:71be9322f4eb 377 for (int i = 0; i < length; i++) {
kennyainny 0:71be9322f4eb 378 _spi.write(buffer[i]);
kennyainny 0:71be9322f4eb 379 }
kennyainny 0:71be9322f4eb 380
kennyainny 0:71be9322f4eb 381 // write the checksum
kennyainny 0:71be9322f4eb 382 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 383 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 384
kennyainny 0:71be9322f4eb 385 // check the response token
kennyainny 0:71be9322f4eb 386 if ((_spi.write(0xFF) & 0x1F) != 0x05) {
kennyainny 0:71be9322f4eb 387 _cs = 1;
kennyainny 0:71be9322f4eb 388 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 389 return 1;
kennyainny 0:71be9322f4eb 390 }
kennyainny 0:71be9322f4eb 391
kennyainny 0:71be9322f4eb 392 // wait for write to finish
kennyainny 0:71be9322f4eb 393 while (_spi.write(0xFF) == 0);
kennyainny 0:71be9322f4eb 394
kennyainny 0:71be9322f4eb 395 _cs = 1;
kennyainny 0:71be9322f4eb 396 _spi.write(0xFF);
kennyainny 0:71be9322f4eb 397 return 0;
kennyainny 0:71be9322f4eb 398 }
kennyainny 0:71be9322f4eb 399
kennyainny 0:71be9322f4eb 400 static uint32_t ext_bits(unsigned char *data, int msb, int lsb) {
kennyainny 0:71be9322f4eb 401 uint32_t bits = 0;
kennyainny 0:71be9322f4eb 402 uint32_t size = 1 + msb - lsb;
kennyainny 0:71be9322f4eb 403 for (int i = 0; i < size; i++) {
kennyainny 0:71be9322f4eb 404 uint32_t position = lsb + i;
kennyainny 0:71be9322f4eb 405 uint32_t byte = 15 - (position >> 3);
kennyainny 0:71be9322f4eb 406 uint32_t bit = position & 0x7;
kennyainny 0:71be9322f4eb 407 uint32_t value = (data[byte] >> bit) & 1;
kennyainny 0:71be9322f4eb 408 bits |= value << i;
kennyainny 0:71be9322f4eb 409 }
kennyainny 0:71be9322f4eb 410 return bits;
kennyainny 0:71be9322f4eb 411 }
kennyainny 0:71be9322f4eb 412
kennyainny 0:71be9322f4eb 413 uint64_t SDFileSystem::_sd_sectors() {
kennyainny 0:71be9322f4eb 414 uint32_t c_size, c_size_mult, read_bl_len;
kennyainny 0:71be9322f4eb 415 uint32_t block_len, mult, blocknr, capacity;
kennyainny 0:71be9322f4eb 416 uint32_t hc_c_size;
kennyainny 0:71be9322f4eb 417 uint64_t blocks;
kennyainny 0:71be9322f4eb 418
kennyainny 0:71be9322f4eb 419 // CMD9, Response R2 (R1 byte + 16-byte block read)
kennyainny 0:71be9322f4eb 420 if (_cmdx(9, 0) != 0) {
kennyainny 0:71be9322f4eb 421 debug("Didn't get a response from the disk\n");
kennyainny 0:71be9322f4eb 422 return 0;
kennyainny 0:71be9322f4eb 423 }
kennyainny 0:71be9322f4eb 424
kennyainny 0:71be9322f4eb 425 uint8_t csd[16];
kennyainny 0:71be9322f4eb 426 if (_read(csd, 16) != 0) {
kennyainny 0:71be9322f4eb 427 debug("Couldn't read csd response from disk\n");
kennyainny 0:71be9322f4eb 428 return 0;
kennyainny 0:71be9322f4eb 429 }
kennyainny 0:71be9322f4eb 430
kennyainny 0:71be9322f4eb 431 // csd_structure : csd[127:126]
kennyainny 0:71be9322f4eb 432 // c_size : csd[73:62]
kennyainny 0:71be9322f4eb 433 // c_size_mult : csd[49:47]
kennyainny 0:71be9322f4eb 434 // read_bl_len : csd[83:80] - the *maximum* read block length
kennyainny 0:71be9322f4eb 435
kennyainny 0:71be9322f4eb 436 int csd_structure = ext_bits(csd, 127, 126);
kennyainny 0:71be9322f4eb 437
kennyainny 0:71be9322f4eb 438 switch (csd_structure) {
kennyainny 0:71be9322f4eb 439 case 0:
kennyainny 0:71be9322f4eb 440 cdv = 512;
kennyainny 0:71be9322f4eb 441 c_size = ext_bits(csd, 73, 62);
kennyainny 0:71be9322f4eb 442 c_size_mult = ext_bits(csd, 49, 47);
kennyainny 0:71be9322f4eb 443 read_bl_len = ext_bits(csd, 83, 80);
kennyainny 0:71be9322f4eb 444
kennyainny 0:71be9322f4eb 445 block_len = 1 << read_bl_len;
kennyainny 0:71be9322f4eb 446 mult = 1 << (c_size_mult + 2);
kennyainny 0:71be9322f4eb 447 blocknr = (c_size + 1) * mult;
kennyainny 0:71be9322f4eb 448 capacity = blocknr * block_len;
kennyainny 0:71be9322f4eb 449 blocks = capacity / 512;
kennyainny 0:71be9322f4eb 450 debug_if(SD_DBG, "\n\rSDCard\n\rc_size: %d \n\rcapacity: %ld \n\rsectors: %lld\n\r", c_size, capacity, blocks);
kennyainny 0:71be9322f4eb 451 break;
kennyainny 0:71be9322f4eb 452
kennyainny 0:71be9322f4eb 453 case 1:
kennyainny 0:71be9322f4eb 454 cdv = 1;
kennyainny 0:71be9322f4eb 455 hc_c_size = ext_bits(csd, 63, 48);
kennyainny 0:71be9322f4eb 456 blocks = (hc_c_size+1)*1024;
kennyainny 0:71be9322f4eb 457 debug_if(SD_DBG, "\n\rSDHC Card \n\rhc_c_size: %d\n\rcapacity: %lld \n\rsectors: %lld\n\r", hc_c_size, blocks*512, blocks);
kennyainny 0:71be9322f4eb 458 break;
kennyainny 0:71be9322f4eb 459
kennyainny 0:71be9322f4eb 460 default:
kennyainny 0:71be9322f4eb 461 debug("CSD struct unsupported\r\n");
kennyainny 0:71be9322f4eb 462 return 0;
kennyainny 0:71be9322f4eb 463 };
kennyainny 0:71be9322f4eb 464 return blocks;
kennyainny 0:71be9322f4eb 465 }