mbed Weather Platform firmware http://mbed.org/users/okini3939/notebook/mbed-weather-platform-firmware/

Dependencies:   EthernetNetIf SDHCFileSystem I2CLEDDisp Agentbed NTPClient_NetServices mbed BMP085 HTTPClient ConfigFile I2CLCD

Committer:
okini3939
Date:
Fri Dec 10 17:15:15 2010 +0000
Revision:
0:4265d973a98f

        

Who changed what in which revision?

UserRevisionLine numberNew contents of line
okini3939 0:4265d973a98f 1 /* mbed SDFileSystem Library, for providing file access to SD cards
okini3939 0:4265d973a98f 2 * Copyright (c) 2008-2010, sford
okini3939 0:4265d973a98f 3 *
okini3939 0:4265d973a98f 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
okini3939 0:4265d973a98f 5 * of this software and associated documentation files (the "Software"), to deal
okini3939 0:4265d973a98f 6 * in the Software without restriction, including without limitation the rights
okini3939 0:4265d973a98f 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
okini3939 0:4265d973a98f 8 * copies of the Software, and to permit persons to whom the Software is
okini3939 0:4265d973a98f 9 * furnished to do so, subject to the following conditions:
okini3939 0:4265d973a98f 10 *
okini3939 0:4265d973a98f 11 * The above copyright notice and this permission notice shall be included in
okini3939 0:4265d973a98f 12 * all copies or substantial portions of the Software.
okini3939 0:4265d973a98f 13 *
okini3939 0:4265d973a98f 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
okini3939 0:4265d973a98f 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
okini3939 0:4265d973a98f 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
okini3939 0:4265d973a98f 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
okini3939 0:4265d973a98f 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
okini3939 0:4265d973a98f 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
okini3939 0:4265d973a98f 20 * THE SOFTWARE.
okini3939 0:4265d973a98f 21 */
okini3939 0:4265d973a98f 22
okini3939 0:4265d973a98f 23 /* Introduction
okini3939 0:4265d973a98f 24 * ------------
okini3939 0:4265d973a98f 25 * SD and MMC cards support a number of interfaces, but common to them all
okini3939 0:4265d973a98f 26 * is one based on SPI. This is the one I'm implmenting because it means
okini3939 0:4265d973a98f 27 * it is much more portable even though not so performant, and we already
okini3939 0:4265d973a98f 28 * have the mbed SPI Interface!
okini3939 0:4265d973a98f 29 *
okini3939 0:4265d973a98f 30 * The main reference I'm using is Chapter 7, "SPI Mode" of:
okini3939 0:4265d973a98f 31 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
okini3939 0:4265d973a98f 32 *
okini3939 0:4265d973a98f 33 * SPI Startup
okini3939 0:4265d973a98f 34 * -----------
okini3939 0:4265d973a98f 35 * The SD card powers up in SD mode. The SPI interface mode is selected by
okini3939 0:4265d973a98f 36 * asserting CS low and sending the reset command (CMD0). The card will
okini3939 0:4265d973a98f 37 * respond with a (R1) response.
okini3939 0:4265d973a98f 38 *
okini3939 0:4265d973a98f 39 * CMD8 is optionally sent to determine the voltage range supported, and
okini3939 0:4265d973a98f 40 * indirectly determine whether it is a version 1.x SD/non-SD card or
okini3939 0:4265d973a98f 41 * version 2.x. I'll just ignore this for now.
okini3939 0:4265d973a98f 42 *
okini3939 0:4265d973a98f 43 * ACMD41 is repeatedly issued to initialise the card, until "in idle"
okini3939 0:4265d973a98f 44 * (bit 0) of the R1 response goes to '0', indicating it is initialised.
okini3939 0:4265d973a98f 45 *
okini3939 0:4265d973a98f 46 * You should also indicate whether the host supports High Capicity cards,
okini3939 0:4265d973a98f 47 * and check whether the card is high capacity - i'll also ignore this
okini3939 0:4265d973a98f 48 *
okini3939 0:4265d973a98f 49 * SPI Protocol
okini3939 0:4265d973a98f 50 * ------------
okini3939 0:4265d973a98f 51 * The SD SPI protocol is based on transactions made up of 8-bit words, with
okini3939 0:4265d973a98f 52 * the host starting every bus transaction by asserting the CS signal low. The
okini3939 0:4265d973a98f 53 * card always responds to commands, data blocks and errors.
okini3939 0:4265d973a98f 54 *
okini3939 0:4265d973a98f 55 * The protocol supports a CRC, but by default it is off (except for the
okini3939 0:4265d973a98f 56 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
okini3939 0:4265d973a98f 57 * I'll leave the CRC off I think!
okini3939 0:4265d973a98f 58 *
okini3939 0:4265d973a98f 59 * Standard capacity cards have variable data block sizes, whereas High
okini3939 0:4265d973a98f 60 * Capacity cards fix the size of data block to 512 bytes. I'll therefore
okini3939 0:4265d973a98f 61 * just always use the Standard Capacity cards with a block size of 512 bytes.
okini3939 0:4265d973a98f 62 * This is set with CMD16.
okini3939 0:4265d973a98f 63 *
okini3939 0:4265d973a98f 64 * You can read and write single blocks (CMD17, CMD25) or multiple blocks
okini3939 0:4265d973a98f 65 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
okini3939 0:4265d973a98f 66 * the card gets a read command, it responds with a response token, and then
okini3939 0:4265d973a98f 67 * a data token or an error.
okini3939 0:4265d973a98f 68 *
okini3939 0:4265d973a98f 69 * SPI Command Format
okini3939 0:4265d973a98f 70 * ------------------
okini3939 0:4265d973a98f 71 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
okini3939 0:4265d973a98f 72 *
okini3939 0:4265d973a98f 73 * +---------------+------------+------------+-----------+----------+--------------+
okini3939 0:4265d973a98f 74 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
okini3939 0:4265d973a98f 75 * +---------------+------------+------------+-----------+----------+--------------+
okini3939 0:4265d973a98f 76 *
okini3939 0:4265d973a98f 77 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
okini3939 0:4265d973a98f 78 *
okini3939 0:4265d973a98f 79 * All Application Specific commands shall be preceded with APP_CMD (CMD55).
okini3939 0:4265d973a98f 80 *
okini3939 0:4265d973a98f 81 * SPI Response Format
okini3939 0:4265d973a98f 82 * -------------------
okini3939 0:4265d973a98f 83 * The main response format (R1) is a status byte (normally zero). Key flags:
okini3939 0:4265d973a98f 84 * idle - 1 if the card is in an idle state/initialising
okini3939 0:4265d973a98f 85 * cmd - 1 if an illegal command code was detected
okini3939 0:4265d973a98f 86 *
okini3939 0:4265d973a98f 87 * +-------------------------------------------------+
okini3939 0:4265d973a98f 88 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
okini3939 0:4265d973a98f 89 * +-------------------------------------------------+
okini3939 0:4265d973a98f 90 *
okini3939 0:4265d973a98f 91 * R1b is the same, except it is followed by a busy signal (zeros) until
okini3939 0:4265d973a98f 92 * the first non-zero byte when it is ready again.
okini3939 0:4265d973a98f 93 *
okini3939 0:4265d973a98f 94 * Data Response Token
okini3939 0:4265d973a98f 95 * -------------------
okini3939 0:4265d973a98f 96 * Every data block written to the card is acknowledged by a byte
okini3939 0:4265d973a98f 97 * response token
okini3939 0:4265d973a98f 98 *
okini3939 0:4265d973a98f 99 * +----------------------+
okini3939 0:4265d973a98f 100 * | xxx | 0 | status | 1 |
okini3939 0:4265d973a98f 101 * +----------------------+
okini3939 0:4265d973a98f 102 * 010 - OK!
okini3939 0:4265d973a98f 103 * 101 - CRC Error
okini3939 0:4265d973a98f 104 * 110 - Write Error
okini3939 0:4265d973a98f 105 *
okini3939 0:4265d973a98f 106 * Single Block Read and Write
okini3939 0:4265d973a98f 107 * ---------------------------
okini3939 0:4265d973a98f 108 *
okini3939 0:4265d973a98f 109 * Block transfers have a byte header, followed by the data, followed
okini3939 0:4265d973a98f 110 * by a 16-bit CRC. In our case, the data will always be 512 bytes.
okini3939 0:4265d973a98f 111 *
okini3939 0:4265d973a98f 112 * +------+---------+---------+- - - -+---------+-----------+----------+
okini3939 0:4265d973a98f 113 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
okini3939 0:4265d973a98f 114 * +------+---------+---------+- - - -+---------+-----------+----------+
okini3939 0:4265d973a98f 115 */
okini3939 0:4265d973a98f 116
okini3939 0:4265d973a98f 117 #include "SDFileSystem.h"
okini3939 0:4265d973a98f 118
okini3939 0:4265d973a98f 119 #define SD_COMMAND_TIMEOUT 5000
okini3939 0:4265d973a98f 120
okini3939 0:4265d973a98f 121 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
okini3939 0:4265d973a98f 122 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
okini3939 0:4265d973a98f 123 _cs = 1;
okini3939 0:4265d973a98f 124 }
okini3939 0:4265d973a98f 125
okini3939 0:4265d973a98f 126 #define R1_IDLE_STATE (1 << 0)
okini3939 0:4265d973a98f 127 #define R1_ERASE_RESET (1 << 1)
okini3939 0:4265d973a98f 128 #define R1_ILLEGAL_COMMAND (1 << 2)
okini3939 0:4265d973a98f 129 #define R1_COM_CRC_ERROR (1 << 3)
okini3939 0:4265d973a98f 130 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
okini3939 0:4265d973a98f 131 #define R1_ADDRESS_ERROR (1 << 5)
okini3939 0:4265d973a98f 132 #define R1_PARAMETER_ERROR (1 << 6)
okini3939 0:4265d973a98f 133
okini3939 0:4265d973a98f 134 // Types
okini3939 0:4265d973a98f 135 // - v1.x Standard Capacity
okini3939 0:4265d973a98f 136 // - v2.x Standard Capacity
okini3939 0:4265d973a98f 137 // - v2.x High Capacity
okini3939 0:4265d973a98f 138 // - Not recognised as an SD Card
okini3939 0:4265d973a98f 139
okini3939 0:4265d973a98f 140 #define SDCARD_FAIL 0
okini3939 0:4265d973a98f 141 #define SDCARD_V1 1
okini3939 0:4265d973a98f 142 #define SDCARD_V2 2
okini3939 0:4265d973a98f 143 #define SDCARD_V2HC 3
okini3939 0:4265d973a98f 144
okini3939 0:4265d973a98f 145 int SDFileSystem::initialise_card() {
okini3939 0:4265d973a98f 146 // Set to 100kHz for initialisation, and clock card with cs = 1
okini3939 0:4265d973a98f 147 _spi.frequency(100000);
okini3939 0:4265d973a98f 148 _cs = 1;
okini3939 0:4265d973a98f 149 for(int i=0; i<16; i++) {
okini3939 0:4265d973a98f 150 _spi.write(0xFF);
okini3939 0:4265d973a98f 151 }
okini3939 0:4265d973a98f 152
okini3939 0:4265d973a98f 153 // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
okini3939 0:4265d973a98f 154 if(_cmd(0, 0) != R1_IDLE_STATE) {
okini3939 0:4265d973a98f 155 fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
okini3939 0:4265d973a98f 156 return SDCARD_FAIL;
okini3939 0:4265d973a98f 157 }
okini3939 0:4265d973a98f 158
okini3939 0:4265d973a98f 159 // send CMD8 to determine whther it is ver 2.x
okini3939 0:4265d973a98f 160 int r = _cmd8();
okini3939 0:4265d973a98f 161 if(r == R1_IDLE_STATE) {
okini3939 0:4265d973a98f 162 return initialise_card_v2();
okini3939 0:4265d973a98f 163 } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
okini3939 0:4265d973a98f 164 return initialise_card_v1();
okini3939 0:4265d973a98f 165 } else {
okini3939 0:4265d973a98f 166 fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
okini3939 0:4265d973a98f 167 return SDCARD_FAIL;
okini3939 0:4265d973a98f 168 }
okini3939 0:4265d973a98f 169 }
okini3939 0:4265d973a98f 170
okini3939 0:4265d973a98f 171 int SDFileSystem::initialise_card_v1() {
okini3939 0:4265d973a98f 172 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:4265d973a98f 173 _cmd(55, 0);
okini3939 0:4265d973a98f 174 if(_cmd(41, 0) == 0) {
okini3939 0:4265d973a98f 175 return SDCARD_V1;
okini3939 0:4265d973a98f 176 }
okini3939 0:4265d973a98f 177 }
okini3939 0:4265d973a98f 178
okini3939 0:4265d973a98f 179 fprintf(stderr, "Timeout waiting for v1.x card\n");
okini3939 0:4265d973a98f 180 return SDCARD_FAIL;
okini3939 0:4265d973a98f 181 }
okini3939 0:4265d973a98f 182
okini3939 0:4265d973a98f 183 int SDFileSystem::initialise_card_v2() {
okini3939 0:4265d973a98f 184
okini3939 0:4265d973a98f 185 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:4265d973a98f 186 _cmd(55, 0);
okini3939 0:4265d973a98f 187 if(_cmd(41, 0) == 0) {
okini3939 0:4265d973a98f 188 _cmd58();
okini3939 0:4265d973a98f 189 return SDCARD_V2;
okini3939 0:4265d973a98f 190 }
okini3939 0:4265d973a98f 191 }
okini3939 0:4265d973a98f 192
okini3939 0:4265d973a98f 193 fprintf(stderr, "Timeout waiting for v2.x card\n");
okini3939 0:4265d973a98f 194 return SDCARD_FAIL;
okini3939 0:4265d973a98f 195 }
okini3939 0:4265d973a98f 196
okini3939 0:4265d973a98f 197 int SDFileSystem::disk_initialize() {
okini3939 0:4265d973a98f 198
okini3939 0:4265d973a98f 199 int i = initialise_card();
okini3939 0:4265d973a98f 200 // printf("init card = %d\n", i);
okini3939 0:4265d973a98f 201 // printf("OK\n");
okini3939 0:4265d973a98f 202
okini3939 0:4265d973a98f 203 _sectors = _sd_sectors();
okini3939 0:4265d973a98f 204
okini3939 0:4265d973a98f 205 // Set block length to 512 (CMD16)
okini3939 0:4265d973a98f 206 if(_cmd(16, 512) != 0) {
okini3939 0:4265d973a98f 207 fprintf(stderr, "Set 512-byte block timed out\n");
okini3939 0:4265d973a98f 208 return 1;
okini3939 0:4265d973a98f 209 }
okini3939 0:4265d973a98f 210
okini3939 0:4265d973a98f 211 _spi.frequency(1000000); // Set to 1MHz for data transfer
okini3939 0:4265d973a98f 212 return 0;
okini3939 0:4265d973a98f 213 }
okini3939 0:4265d973a98f 214
okini3939 0:4265d973a98f 215 int SDFileSystem::disk_write(const char *buffer, int block_number) {
okini3939 0:4265d973a98f 216 // set write address for single block (CMD24)
okini3939 0:4265d973a98f 217 if(_cmd(24, block_number * 512) != 0) {
okini3939 0:4265d973a98f 218 return 1;
okini3939 0:4265d973a98f 219 }
okini3939 0:4265d973a98f 220
okini3939 0:4265d973a98f 221 // send the data block
okini3939 0:4265d973a98f 222 _write(buffer, 512);
okini3939 0:4265d973a98f 223 return 0;
okini3939 0:4265d973a98f 224 }
okini3939 0:4265d973a98f 225
okini3939 0:4265d973a98f 226 int SDFileSystem::disk_read(char *buffer, int block_number) {
okini3939 0:4265d973a98f 227 // set read address for single block (CMD17)
okini3939 0:4265d973a98f 228 if(_cmd(17, block_number * 512) != 0) {
okini3939 0:4265d973a98f 229 return 1;
okini3939 0:4265d973a98f 230 }
okini3939 0:4265d973a98f 231
okini3939 0:4265d973a98f 232 // receive the data
okini3939 0:4265d973a98f 233 _read(buffer, 512);
okini3939 0:4265d973a98f 234 return 0;
okini3939 0:4265d973a98f 235 }
okini3939 0:4265d973a98f 236
okini3939 0:4265d973a98f 237 int SDFileSystem::disk_status() { return 0; }
okini3939 0:4265d973a98f 238 int SDFileSystem::disk_sync() { return 0; }
okini3939 0:4265d973a98f 239 int SDFileSystem::disk_sectors() { return _sectors; }
okini3939 0:4265d973a98f 240
okini3939 0:4265d973a98f 241 // PRIVATE FUNCTIONS
okini3939 0:4265d973a98f 242
okini3939 0:4265d973a98f 243 int SDFileSystem::_cmd(int cmd, int arg) {
okini3939 0:4265d973a98f 244 _cs = 0;
okini3939 0:4265d973a98f 245
okini3939 0:4265d973a98f 246 // send a command
okini3939 0:4265d973a98f 247 _spi.write(0x40 | cmd);
okini3939 0:4265d973a98f 248 _spi.write(arg >> 24);
okini3939 0:4265d973a98f 249 _spi.write(arg >> 16);
okini3939 0:4265d973a98f 250 _spi.write(arg >> 8);
okini3939 0:4265d973a98f 251 _spi.write(arg >> 0);
okini3939 0:4265d973a98f 252 _spi.write(0x95);
okini3939 0:4265d973a98f 253
okini3939 0:4265d973a98f 254 // wait for the repsonse (response[7] == 0)
okini3939 0:4265d973a98f 255 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:4265d973a98f 256 int response = _spi.write(0xFF);
okini3939 0:4265d973a98f 257 if(!(response & 0x80)) {
okini3939 0:4265d973a98f 258 _cs = 1;
okini3939 0:4265d973a98f 259 _spi.write(0xFF);
okini3939 0:4265d973a98f 260 return response;
okini3939 0:4265d973a98f 261 }
okini3939 0:4265d973a98f 262 }
okini3939 0:4265d973a98f 263 _cs = 1;
okini3939 0:4265d973a98f 264 _spi.write(0xFF);
okini3939 0:4265d973a98f 265 return -1; // timeout
okini3939 0:4265d973a98f 266 }
okini3939 0:4265d973a98f 267 int SDFileSystem::_cmdx(int cmd, int arg) {
okini3939 0:4265d973a98f 268 _cs = 0;
okini3939 0:4265d973a98f 269
okini3939 0:4265d973a98f 270 // send a command
okini3939 0:4265d973a98f 271 _spi.write(0x40 | cmd);
okini3939 0:4265d973a98f 272 _spi.write(arg >> 24);
okini3939 0:4265d973a98f 273 _spi.write(arg >> 16);
okini3939 0:4265d973a98f 274 _spi.write(arg >> 8);
okini3939 0:4265d973a98f 275 _spi.write(arg >> 0);
okini3939 0:4265d973a98f 276 _spi.write(0x95);
okini3939 0:4265d973a98f 277
okini3939 0:4265d973a98f 278 // wait for the repsonse (response[7] == 0)
okini3939 0:4265d973a98f 279 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:4265d973a98f 280 int response = _spi.write(0xFF);
okini3939 0:4265d973a98f 281 if(!(response & 0x80)) {
okini3939 0:4265d973a98f 282 return response;
okini3939 0:4265d973a98f 283 }
okini3939 0:4265d973a98f 284 }
okini3939 0:4265d973a98f 285 _cs = 1;
okini3939 0:4265d973a98f 286 _spi.write(0xFF);
okini3939 0:4265d973a98f 287 return -1; // timeout
okini3939 0:4265d973a98f 288 }
okini3939 0:4265d973a98f 289
okini3939 0:4265d973a98f 290
okini3939 0:4265d973a98f 291 int SDFileSystem::_cmd58() {
okini3939 0:4265d973a98f 292 _cs = 0;
okini3939 0:4265d973a98f 293 int arg = 0;
okini3939 0:4265d973a98f 294
okini3939 0:4265d973a98f 295 // send a command
okini3939 0:4265d973a98f 296 _spi.write(0x40 | 58);
okini3939 0:4265d973a98f 297 _spi.write(arg >> 24);
okini3939 0:4265d973a98f 298 _spi.write(arg >> 16);
okini3939 0:4265d973a98f 299 _spi.write(arg >> 8);
okini3939 0:4265d973a98f 300 _spi.write(arg >> 0);
okini3939 0:4265d973a98f 301 _spi.write(0x95);
okini3939 0:4265d973a98f 302
okini3939 0:4265d973a98f 303 // wait for the repsonse (response[7] == 0)
okini3939 0:4265d973a98f 304 for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
okini3939 0:4265d973a98f 305 int response = _spi.write(0xFF);
okini3939 0:4265d973a98f 306 if(!(response & 0x80)) {
okini3939 0:4265d973a98f 307 int ocr = _spi.write(0xFF) << 24;
okini3939 0:4265d973a98f 308 ocr |= _spi.write(0xFF) << 16;
okini3939 0:4265d973a98f 309 ocr |= _spi.write(0xFF) << 8;
okini3939 0:4265d973a98f 310 ocr |= _spi.write(0xFF) << 0;
okini3939 0:4265d973a98f 311 // printf("OCR = 0x%08X\n", ocr);
okini3939 0:4265d973a98f 312 _cs = 1;
okini3939 0:4265d973a98f 313 _spi.write(0xFF);
okini3939 0:4265d973a98f 314 return response;
okini3939 0:4265d973a98f 315 }
okini3939 0:4265d973a98f 316 }
okini3939 0:4265d973a98f 317 _cs = 1;
okini3939 0:4265d973a98f 318 _spi.write(0xFF);
okini3939 0:4265d973a98f 319 return -1; // timeout
okini3939 0:4265d973a98f 320 }
okini3939 0:4265d973a98f 321
okini3939 0:4265d973a98f 322 int SDFileSystem::_cmd8() {
okini3939 0:4265d973a98f 323 _cs = 0;
okini3939 0:4265d973a98f 324
okini3939 0:4265d973a98f 325 // send a command
okini3939 0:4265d973a98f 326 _spi.write(0x40 | 8); // CMD8
okini3939 0:4265d973a98f 327 _spi.write(0x00); // reserved
okini3939 0:4265d973a98f 328 _spi.write(0x00); // reserved
okini3939 0:4265d973a98f 329 _spi.write(0x01); // 3.3v
okini3939 0:4265d973a98f 330 _spi.write(0xAA); // check pattern
okini3939 0:4265d973a98f 331 _spi.write(0x87); // crc
okini3939 0:4265d973a98f 332
okini3939 0:4265d973a98f 333 // wait for the repsonse (response[7] == 0)
okini3939 0:4265d973a98f 334 for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
okini3939 0:4265d973a98f 335 char response[5];
okini3939 0:4265d973a98f 336 response[0] = _spi.write(0xFF);
okini3939 0:4265d973a98f 337 if(!(response[0] & 0x80)) {
okini3939 0:4265d973a98f 338 for(int j=1; j<5; j++) {
okini3939 0:4265d973a98f 339 response[i] = _spi.write(0xFF);
okini3939 0:4265d973a98f 340 }
okini3939 0:4265d973a98f 341 _cs = 1;
okini3939 0:4265d973a98f 342 _spi.write(0xFF);
okini3939 0:4265d973a98f 343 return response[0];
okini3939 0:4265d973a98f 344 }
okini3939 0:4265d973a98f 345 }
okini3939 0:4265d973a98f 346 _cs = 1;
okini3939 0:4265d973a98f 347 _spi.write(0xFF);
okini3939 0:4265d973a98f 348 return -1; // timeout
okini3939 0:4265d973a98f 349 }
okini3939 0:4265d973a98f 350
okini3939 0:4265d973a98f 351 int SDFileSystem::_read(char *buffer, int length) {
okini3939 0:4265d973a98f 352 _cs = 0;
okini3939 0:4265d973a98f 353
okini3939 0:4265d973a98f 354 // read until start byte (0xFF)
okini3939 0:4265d973a98f 355 while(_spi.write(0xFF) != 0xFE);
okini3939 0:4265d973a98f 356
okini3939 0:4265d973a98f 357 // read data
okini3939 0:4265d973a98f 358 for(int i=0; i<length; i++) {
okini3939 0:4265d973a98f 359 buffer[i] = _spi.write(0xFF);
okini3939 0:4265d973a98f 360 }
okini3939 0:4265d973a98f 361 _spi.write(0xFF); // checksum
okini3939 0:4265d973a98f 362 _spi.write(0xFF);
okini3939 0:4265d973a98f 363
okini3939 0:4265d973a98f 364 _cs = 1;
okini3939 0:4265d973a98f 365 _spi.write(0xFF);
okini3939 0:4265d973a98f 366 return 0;
okini3939 0:4265d973a98f 367 }
okini3939 0:4265d973a98f 368
okini3939 0:4265d973a98f 369 int SDFileSystem::_write(const char *buffer, int length) {
okini3939 0:4265d973a98f 370 _cs = 0;
okini3939 0:4265d973a98f 371
okini3939 0:4265d973a98f 372 // indicate start of block
okini3939 0:4265d973a98f 373 _spi.write(0xFE);
okini3939 0:4265d973a98f 374
okini3939 0:4265d973a98f 375 // write the data
okini3939 0:4265d973a98f 376 for(int i=0; i<length; i++) {
okini3939 0:4265d973a98f 377 _spi.write(buffer[i]);
okini3939 0:4265d973a98f 378 }
okini3939 0:4265d973a98f 379
okini3939 0:4265d973a98f 380 // write the checksum
okini3939 0:4265d973a98f 381 _spi.write(0xFF);
okini3939 0:4265d973a98f 382 _spi.write(0xFF);
okini3939 0:4265d973a98f 383
okini3939 0:4265d973a98f 384 // check the repsonse token
okini3939 0:4265d973a98f 385 if((_spi.write(0xFF) & 0x1F) != 0x05) {
okini3939 0:4265d973a98f 386 _cs = 1;
okini3939 0:4265d973a98f 387 _spi.write(0xFF);
okini3939 0:4265d973a98f 388 return 1;
okini3939 0:4265d973a98f 389 }
okini3939 0:4265d973a98f 390
okini3939 0:4265d973a98f 391 // wait for write to finish
okini3939 0:4265d973a98f 392 while(_spi.write(0xFF) == 0);
okini3939 0:4265d973a98f 393
okini3939 0:4265d973a98f 394 _cs = 1;
okini3939 0:4265d973a98f 395 _spi.write(0xFF);
okini3939 0:4265d973a98f 396 return 0;
okini3939 0:4265d973a98f 397 }
okini3939 0:4265d973a98f 398
okini3939 0:4265d973a98f 399 static int ext_bits(char *data, int msb, int lsb) {
okini3939 0:4265d973a98f 400 int bits = 0;
okini3939 0:4265d973a98f 401 int size = 1 + msb - lsb;
okini3939 0:4265d973a98f 402 for(int i=0; i<size; i++) {
okini3939 0:4265d973a98f 403 int position = lsb + i;
okini3939 0:4265d973a98f 404 int byte = 15 - (position >> 3);
okini3939 0:4265d973a98f 405 int bit = position & 0x7;
okini3939 0:4265d973a98f 406 int value = (data[byte] >> bit) & 1;
okini3939 0:4265d973a98f 407 bits |= value << i;
okini3939 0:4265d973a98f 408 }
okini3939 0:4265d973a98f 409 return bits;
okini3939 0:4265d973a98f 410 }
okini3939 0:4265d973a98f 411
okini3939 0:4265d973a98f 412 int SDFileSystem::_sd_sectors() {
okini3939 0:4265d973a98f 413
okini3939 0:4265d973a98f 414 // CMD9, Response R2 (R1 byte + 16-byte block read)
okini3939 0:4265d973a98f 415 if(_cmdx(9, 0) != 0) {
okini3939 0:4265d973a98f 416 fprintf(stderr, "Didn't get a response from the disk\n");
okini3939 0:4265d973a98f 417 return 0;
okini3939 0:4265d973a98f 418 }
okini3939 0:4265d973a98f 419
okini3939 0:4265d973a98f 420 char csd[16];
okini3939 0:4265d973a98f 421 if(_read(csd, 16) != 0) {
okini3939 0:4265d973a98f 422 fprintf(stderr, "Couldn't read csd response from disk\n");
okini3939 0:4265d973a98f 423 return 0;
okini3939 0:4265d973a98f 424 }
okini3939 0:4265d973a98f 425
okini3939 0:4265d973a98f 426 // csd_structure : csd[127:126]
okini3939 0:4265d973a98f 427 // c_size : csd[73:62]
okini3939 0:4265d973a98f 428 // c_size_mult : csd[49:47]
okini3939 0:4265d973a98f 429 // read_bl_len : csd[83:80] - the *maximum* read block length
okini3939 0:4265d973a98f 430
okini3939 0:4265d973a98f 431 int csd_structure = ext_bits(csd, 127, 126);
okini3939 0:4265d973a98f 432 int c_size = ext_bits(csd, 73, 62);
okini3939 0:4265d973a98f 433 int c_size_mult = ext_bits(csd, 49, 47);
okini3939 0:4265d973a98f 434 int read_bl_len = ext_bits(csd, 83, 80);
okini3939 0:4265d973a98f 435
okini3939 0:4265d973a98f 436 // printf("CSD_STRUCT = %d\n", csd_structure);
okini3939 0:4265d973a98f 437
okini3939 0:4265d973a98f 438 if(csd_structure != 0) {
okini3939 0:4265d973a98f 439 fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
okini3939 0:4265d973a98f 440 return 0;
okini3939 0:4265d973a98f 441 }
okini3939 0:4265d973a98f 442
okini3939 0:4265d973a98f 443 // memory capacity = BLOCKNR * BLOCK_LEN
okini3939 0:4265d973a98f 444 // where
okini3939 0:4265d973a98f 445 // BLOCKNR = (C_SIZE+1) * MULT
okini3939 0:4265d973a98f 446 // MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
okini3939 0:4265d973a98f 447 // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
okini3939 0:4265d973a98f 448
okini3939 0:4265d973a98f 449 int block_len = 1 << read_bl_len;
okini3939 0:4265d973a98f 450 int mult = 1 << (c_size_mult + 2);
okini3939 0:4265d973a98f 451 int blocknr = (c_size + 1) * mult;
okini3939 0:4265d973a98f 452 int capacity = blocknr * block_len;
okini3939 0:4265d973a98f 453
okini3939 0:4265d973a98f 454 int blocks = capacity / 512;
okini3939 0:4265d973a98f 455
okini3939 0:4265d973a98f 456 return blocks;
okini3939 0:4265d973a98f 457 }