Chris Styles
Simon Fords SDCard library exported without a main.cpp and mbed.lib. Import files into your own project for all the SDCard fun you can have!
SDFileSystem.cpp@0:fc0e38551beb, 2010-02-20 (annotated)
- Committer:
- chris
- Date:
- Sat Feb 20 08:17:35 2010 +0000
- Revision:
- 0:fc0e38551beb
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| chris | 0:fc0e38551beb | 1 | /* mbed Microcontroller Library - SDFileSystem |
| chris | 0:fc0e38551beb | 2 | * Copyright (c) 2008-2009, sford |
| chris | 0:fc0e38551beb | 3 | */ |
| chris | 0:fc0e38551beb | 4 | |
| chris | 0:fc0e38551beb | 5 | // VERY DRAFT CODE! Needs serious rework/refactoring |
| chris | 0:fc0e38551beb | 6 | |
| chris | 0:fc0e38551beb | 7 | /* Introduction |
| chris | 0:fc0e38551beb | 8 | * ------------ |
| chris | 0:fc0e38551beb | 9 | * SD and MMC cards support a number of interfaces, but common to them all |
| chris | 0:fc0e38551beb | 10 | * is one based on SPI. This is the one I'm implmenting because it means |
| chris | 0:fc0e38551beb | 11 | * it is much more portable even though not so performant, and we already |
| chris | 0:fc0e38551beb | 12 | * have the mbed SPI Interface! |
| chris | 0:fc0e38551beb | 13 | * |
| chris | 0:fc0e38551beb | 14 | * The main reference I'm using is Chapter 7, "SPI Mode" of: |
| chris | 0:fc0e38551beb | 15 | * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf |
| chris | 0:fc0e38551beb | 16 | * |
| chris | 0:fc0e38551beb | 17 | * SPI Startup |
| chris | 0:fc0e38551beb | 18 | * ----------- |
| chris | 0:fc0e38551beb | 19 | * The SD card powers up in SD mode. The SPI interface mode is selected by |
| chris | 0:fc0e38551beb | 20 | * asserting CS low and sending the reset command (CMD0). The card will |
| chris | 0:fc0e38551beb | 21 | * respond with a (R1) response. |
| chris | 0:fc0e38551beb | 22 | * |
| chris | 0:fc0e38551beb | 23 | * CMD8 is optionally sent to determine the voltage range supported, and |
| chris | 0:fc0e38551beb | 24 | * indirectly determine whether it is a version 1.x SD/non-SD card or |
| chris | 0:fc0e38551beb | 25 | * version 2.x. I'll just ignore this for now. |
| chris | 0:fc0e38551beb | 26 | * |
| chris | 0:fc0e38551beb | 27 | * ACMD41 is repeatedly issued to initialise the card, until "in idle" |
| chris | 0:fc0e38551beb | 28 | * (bit 0) of the R1 response goes to '0', indicating it is initialised. |
| chris | 0:fc0e38551beb | 29 | * |
| chris | 0:fc0e38551beb | 30 | * You should also indicate whether the host supports High Capicity cards, |
| chris | 0:fc0e38551beb | 31 | * and check whether the card is high capacity - i'll also ignore this |
| chris | 0:fc0e38551beb | 32 | * |
| chris | 0:fc0e38551beb | 33 | * SPI Protocol |
| chris | 0:fc0e38551beb | 34 | * ------------ |
| chris | 0:fc0e38551beb | 35 | * The SD SPI protocol is based on transactions made up of 8-bit words, with |
| chris | 0:fc0e38551beb | 36 | * the host starting every bus transaction by asserting the CS signal low. The |
| chris | 0:fc0e38551beb | 37 | * card always responds to commands, data blocks and errors. |
| chris | 0:fc0e38551beb | 38 | * |
| chris | 0:fc0e38551beb | 39 | * The protocol supports a CRC, but by default it is off (except for the |
| chris | 0:fc0e38551beb | 40 | * first reset CMD0, where the CRC can just be pre-calculated, and CMD8) |
| chris | 0:fc0e38551beb | 41 | * I'll leave the CRC off I think! |
| chris | 0:fc0e38551beb | 42 | * |
| chris | 0:fc0e38551beb | 43 | * Standard capacity cards have variable data block sizes, whereas High |
| chris | 0:fc0e38551beb | 44 | * Capacity cards fix the size of data block to 512 bytes. I'll therefore |
| chris | 0:fc0e38551beb | 45 | * just always use the Standard Capacity cards with a block size of 512 bytes. |
| chris | 0:fc0e38551beb | 46 | * This is set with CMD16. |
| chris | 0:fc0e38551beb | 47 | * |
| chris | 0:fc0e38551beb | 48 | * You can read and write single blocks (CMD17, CMD25) or multiple blocks |
| chris | 0:fc0e38551beb | 49 | * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When |
| chris | 0:fc0e38551beb | 50 | * the card gets a read command, it responds with a response token, and then |
| chris | 0:fc0e38551beb | 51 | * a data token or an error. |
| chris | 0:fc0e38551beb | 52 | * |
| chris | 0:fc0e38551beb | 53 | * SPI Command Format |
| chris | 0:fc0e38551beb | 54 | * ------------------ |
| chris | 0:fc0e38551beb | 55 | * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC. |
| chris | 0:fc0e38551beb | 56 | * |
| chris | 0:fc0e38551beb | 57 | * +---------------+------------+------------+-----------+----------+--------------+ |
| chris | 0:fc0e38551beb | 58 | * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 | |
| chris | 0:fc0e38551beb | 59 | * +---------------+------------+------------+-----------+----------+--------------+ |
| chris | 0:fc0e38551beb | 60 | * |
| chris | 0:fc0e38551beb | 61 | * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95) |
| chris | 0:fc0e38551beb | 62 | * |
| chris | 0:fc0e38551beb | 63 | * All Application Specific commands shall be preceded with APP_CMD (CMD55). |
| chris | 0:fc0e38551beb | 64 | * |
| chris | 0:fc0e38551beb | 65 | * SPI Response Format |
| chris | 0:fc0e38551beb | 66 | * ------------------- |
| chris | 0:fc0e38551beb | 67 | * The main response format (R1) is a status byte (normally zero). Key flags: |
| chris | 0:fc0e38551beb | 68 | * idle - 1 if the card is in an idle state/initialising |
| chris | 0:fc0e38551beb | 69 | * cmd - 1 if an illegal command code was detected |
| chris | 0:fc0e38551beb | 70 | * |
| chris | 0:fc0e38551beb | 71 | * +-------------------------------------------------+ |
| chris | 0:fc0e38551beb | 72 | * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle | |
| chris | 0:fc0e38551beb | 73 | * +-------------------------------------------------+ |
| chris | 0:fc0e38551beb | 74 | * |
| chris | 0:fc0e38551beb | 75 | * R1b is the same, except it is followed by a busy signal (zeros) until |
| chris | 0:fc0e38551beb | 76 | * the first non-zero byte when it is ready again. |
| chris | 0:fc0e38551beb | 77 | * |
| chris | 0:fc0e38551beb | 78 | * Data Response Token |
| chris | 0:fc0e38551beb | 79 | * ------------------- |
| chris | 0:fc0e38551beb | 80 | * Every data block written to the card is acknowledged by a byte |
| chris | 0:fc0e38551beb | 81 | * response token |
| chris | 0:fc0e38551beb | 82 | * |
| chris | 0:fc0e38551beb | 83 | * +----------------------+ |
| chris | 0:fc0e38551beb | 84 | * | xxx | 0 | status | 1 | |
| chris | 0:fc0e38551beb | 85 | * +----------------------+ |
| chris | 0:fc0e38551beb | 86 | * 010 - OK! |
| chris | 0:fc0e38551beb | 87 | * 101 - CRC Error |
| chris | 0:fc0e38551beb | 88 | * 110 - Write Error |
| chris | 0:fc0e38551beb | 89 | * |
| chris | 0:fc0e38551beb | 90 | * Single Block Read and Write |
| chris | 0:fc0e38551beb | 91 | * --------------------------- |
| chris | 0:fc0e38551beb | 92 | * |
| chris | 0:fc0e38551beb | 93 | * Block transfers have a byte header, followed by the data, followed |
| chris | 0:fc0e38551beb | 94 | * by a 16-bit CRC. In our case, the data will always be 512 bytes. |
| chris | 0:fc0e38551beb | 95 | * |
| chris | 0:fc0e38551beb | 96 | * +------+---------+---------+- - - -+---------+-----------+----------+ |
| chris | 0:fc0e38551beb | 97 | * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] | |
| chris | 0:fc0e38551beb | 98 | * +------+---------+---------+- - - -+---------+-----------+----------+ |
| chris | 0:fc0e38551beb | 99 | */ |
| chris | 0:fc0e38551beb | 100 | |
| chris | 0:fc0e38551beb | 101 | #include "SDFileSystem.h" |
| chris | 0:fc0e38551beb | 102 | |
| chris | 0:fc0e38551beb | 103 | #define SD_COMMAND_TIMEOUT 5000 |
| chris | 0:fc0e38551beb | 104 | |
| chris | 0:fc0e38551beb | 105 | SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) : |
| chris | 0:fc0e38551beb | 106 | FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) { |
| chris | 0:fc0e38551beb | 107 | _cs = 1; |
| chris | 0:fc0e38551beb | 108 | } |
| chris | 0:fc0e38551beb | 109 | |
| chris | 0:fc0e38551beb | 110 | #define R1_IDLE_STATE (1 << 0) |
| chris | 0:fc0e38551beb | 111 | #define R1_ERASE_RESET (1 << 1) |
| chris | 0:fc0e38551beb | 112 | #define R1_ILLEGAL_COMMAND (1 << 2) |
| chris | 0:fc0e38551beb | 113 | #define R1_COM_CRC_ERROR (1 << 3) |
| chris | 0:fc0e38551beb | 114 | #define R1_ERASE_SEQUENCE_ERROR (1 << 4) |
| chris | 0:fc0e38551beb | 115 | #define R1_ADDRESS_ERROR (1 << 5) |
| chris | 0:fc0e38551beb | 116 | #define R1_PARAMETER_ERROR (1 << 6) |
| chris | 0:fc0e38551beb | 117 | |
| chris | 0:fc0e38551beb | 118 | // Types |
| chris | 0:fc0e38551beb | 119 | // - v1.x Standard Capacity |
| chris | 0:fc0e38551beb | 120 | // - v2.x Standard Capacity |
| chris | 0:fc0e38551beb | 121 | // - v2.x High Capacity |
| chris | 0:fc0e38551beb | 122 | // - Not recognised as an SD Card |
| chris | 0:fc0e38551beb | 123 | |
| chris | 0:fc0e38551beb | 124 | #define SDCARD_FAIL 0 |
| chris | 0:fc0e38551beb | 125 | #define SDCARD_V1 1 |
| chris | 0:fc0e38551beb | 126 | #define SDCARD_V2 2 |
| chris | 0:fc0e38551beb | 127 | #define SDCARD_V2HC 3 |
| chris | 0:fc0e38551beb | 128 | |
| chris | 0:fc0e38551beb | 129 | int SDFileSystem::initialise_card() { |
| chris | 0:fc0e38551beb | 130 | // Set to 100kHz for initialisation, and clock card with cs = 1 |
| chris | 0:fc0e38551beb | 131 | _spi.frequency(100000); |
| chris | 0:fc0e38551beb | 132 | _cs = 1; |
| chris | 0:fc0e38551beb | 133 | for(int i=0; i<16; i++) { |
| chris | 0:fc0e38551beb | 134 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 135 | } |
| chris | 0:fc0e38551beb | 136 | |
| chris | 0:fc0e38551beb | 137 | // send CMD0, should return with all zeros except IDLE STATE set (bit 0) |
| chris | 0:fc0e38551beb | 138 | if(_cmd(0, 0) != R1_IDLE_STATE) { |
| chris | 0:fc0e38551beb | 139 | fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n"); |
| chris | 0:fc0e38551beb | 140 | return SDCARD_FAIL; |
| chris | 0:fc0e38551beb | 141 | } |
| chris | 0:fc0e38551beb | 142 | |
| chris | 0:fc0e38551beb | 143 | // send CMD8 to determine whther it is ver 2.x |
| chris | 0:fc0e38551beb | 144 | int r = _cmd8(); |
| chris | 0:fc0e38551beb | 145 | if(r == R1_IDLE_STATE) { |
| chris | 0:fc0e38551beb | 146 | return initialise_card_v2(); |
| chris | 0:fc0e38551beb | 147 | } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) { |
| chris | 0:fc0e38551beb | 148 | return initialise_card_v1(); |
| chris | 0:fc0e38551beb | 149 | } else { |
| chris | 0:fc0e38551beb | 150 | fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n"); |
| chris | 0:fc0e38551beb | 151 | return SDCARD_FAIL; |
| chris | 0:fc0e38551beb | 152 | } |
| chris | 0:fc0e38551beb | 153 | } |
| chris | 0:fc0e38551beb | 154 | |
| chris | 0:fc0e38551beb | 155 | int SDFileSystem::initialise_card_v1() { |
| chris | 0:fc0e38551beb | 156 | for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { |
| chris | 0:fc0e38551beb | 157 | _cmd(55, 0); |
| chris | 0:fc0e38551beb | 158 | if(_cmd(41, 0) == 0) { |
| chris | 0:fc0e38551beb | 159 | return SDCARD_V1; |
| chris | 0:fc0e38551beb | 160 | } |
| chris | 0:fc0e38551beb | 161 | } |
| chris | 0:fc0e38551beb | 162 | |
| chris | 0:fc0e38551beb | 163 | fprintf(stderr, "Timeout waiting for v1.x card\n"); |
| chris | 0:fc0e38551beb | 164 | return SDCARD_FAIL; |
| chris | 0:fc0e38551beb | 165 | } |
| chris | 0:fc0e38551beb | 166 | |
| chris | 0:fc0e38551beb | 167 | int SDFileSystem::initialise_card_v2() { |
| chris | 0:fc0e38551beb | 168 | |
| chris | 0:fc0e38551beb | 169 | for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { |
| chris | 0:fc0e38551beb | 170 | _cmd(55, 0); |
| chris | 0:fc0e38551beb | 171 | if(_cmd(41, 0) == 0) { |
| chris | 0:fc0e38551beb | 172 | _cmd58(); |
| chris | 0:fc0e38551beb | 173 | return SDCARD_V2; |
| chris | 0:fc0e38551beb | 174 | } |
| chris | 0:fc0e38551beb | 175 | } |
| chris | 0:fc0e38551beb | 176 | |
| chris | 0:fc0e38551beb | 177 | fprintf(stderr, "Timeout waiting for v2.x card\n"); |
| chris | 0:fc0e38551beb | 178 | return SDCARD_FAIL; |
| chris | 0:fc0e38551beb | 179 | } |
| chris | 0:fc0e38551beb | 180 | |
| chris | 0:fc0e38551beb | 181 | int SDFileSystem::disk_initialize() { |
| chris | 0:fc0e38551beb | 182 | |
| chris | 0:fc0e38551beb | 183 | int i = initialise_card(); |
| chris | 0:fc0e38551beb | 184 | // printf("init card = %d\n", i); |
| chris | 0:fc0e38551beb | 185 | // printf("OK\n"); |
| chris | 0:fc0e38551beb | 186 | |
| chris | 0:fc0e38551beb | 187 | _sectors = _sd_sectors(); |
| chris | 0:fc0e38551beb | 188 | |
| chris | 0:fc0e38551beb | 189 | // Set block length to 512 (CMD16) |
| chris | 0:fc0e38551beb | 190 | if(_cmd(16, 512) != 0) { |
| chris | 0:fc0e38551beb | 191 | fprintf(stderr, "Set 512-byte block timed out\n"); |
| chris | 0:fc0e38551beb | 192 | return 1; |
| chris | 0:fc0e38551beb | 193 | } |
| chris | 0:fc0e38551beb | 194 | |
| chris | 0:fc0e38551beb | 195 | _spi.frequency(1000000); // Set to 1MHz for data transfer |
| chris | 0:fc0e38551beb | 196 | return 0; |
| chris | 0:fc0e38551beb | 197 | } |
| chris | 0:fc0e38551beb | 198 | |
| chris | 0:fc0e38551beb | 199 | int SDFileSystem::disk_write(const char *buffer, int block_number) { |
| chris | 0:fc0e38551beb | 200 | // set write address for single block (CMD24) |
| chris | 0:fc0e38551beb | 201 | if(_cmd(24, block_number * 512) != 0) { |
| chris | 0:fc0e38551beb | 202 | return 1; |
| chris | 0:fc0e38551beb | 203 | } |
| chris | 0:fc0e38551beb | 204 | |
| chris | 0:fc0e38551beb | 205 | // send the data block |
| chris | 0:fc0e38551beb | 206 | _write(buffer, 512); |
| chris | 0:fc0e38551beb | 207 | return 0; |
| chris | 0:fc0e38551beb | 208 | } |
| chris | 0:fc0e38551beb | 209 | |
| chris | 0:fc0e38551beb | 210 | int SDFileSystem::disk_read(char *buffer, int block_number) { |
| chris | 0:fc0e38551beb | 211 | // set read address for single block (CMD17) |
| chris | 0:fc0e38551beb | 212 | if(_cmd(17, block_number * 512) != 0) { |
| chris | 0:fc0e38551beb | 213 | return 1; |
| chris | 0:fc0e38551beb | 214 | } |
| chris | 0:fc0e38551beb | 215 | |
| chris | 0:fc0e38551beb | 216 | // receive the data |
| chris | 0:fc0e38551beb | 217 | _read(buffer, 512); |
| chris | 0:fc0e38551beb | 218 | return 0; |
| chris | 0:fc0e38551beb | 219 | } |
| chris | 0:fc0e38551beb | 220 | |
| chris | 0:fc0e38551beb | 221 | int SDFileSystem::disk_status() { return 0; } |
| chris | 0:fc0e38551beb | 222 | int SDFileSystem::disk_sync() { return 0; } |
| chris | 0:fc0e38551beb | 223 | int SDFileSystem::disk_sectors() { return _sectors; } |
| chris | 0:fc0e38551beb | 224 | |
| chris | 0:fc0e38551beb | 225 | // PRIVATE FUNCTIONS |
| chris | 0:fc0e38551beb | 226 | |
| chris | 0:fc0e38551beb | 227 | int SDFileSystem::_cmd(int cmd, int arg) { |
| chris | 0:fc0e38551beb | 228 | _cs = 0; |
| chris | 0:fc0e38551beb | 229 | |
| chris | 0:fc0e38551beb | 230 | // send a command |
| chris | 0:fc0e38551beb | 231 | _spi.write(0x40 | cmd); |
| chris | 0:fc0e38551beb | 232 | _spi.write(arg >> 24); |
| chris | 0:fc0e38551beb | 233 | _spi.write(arg >> 16); |
| chris | 0:fc0e38551beb | 234 | _spi.write(arg >> 8); |
| chris | 0:fc0e38551beb | 235 | _spi.write(arg >> 0); |
| chris | 0:fc0e38551beb | 236 | _spi.write(0x95); |
| chris | 0:fc0e38551beb | 237 | |
| chris | 0:fc0e38551beb | 238 | // wait for the repsonse (response[7] == 0) |
| chris | 0:fc0e38551beb | 239 | for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { |
| chris | 0:fc0e38551beb | 240 | int response = _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 241 | if(!(response & 0x80)) { |
| chris | 0:fc0e38551beb | 242 | _cs = 1; |
| chris | 0:fc0e38551beb | 243 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 244 | return response; |
| chris | 0:fc0e38551beb | 245 | } |
| chris | 0:fc0e38551beb | 246 | } |
| chris | 0:fc0e38551beb | 247 | _cs = 1; |
| chris | 0:fc0e38551beb | 248 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 249 | return -1; // timeout |
| chris | 0:fc0e38551beb | 250 | } |
| chris | 0:fc0e38551beb | 251 | int SDFileSystem::_cmdx(int cmd, int arg) { |
| chris | 0:fc0e38551beb | 252 | _cs = 0; |
| chris | 0:fc0e38551beb | 253 | |
| chris | 0:fc0e38551beb | 254 | // send a command |
| chris | 0:fc0e38551beb | 255 | _spi.write(0x40 | cmd); |
| chris | 0:fc0e38551beb | 256 | _spi.write(arg >> 24); |
| chris | 0:fc0e38551beb | 257 | _spi.write(arg >> 16); |
| chris | 0:fc0e38551beb | 258 | _spi.write(arg >> 8); |
| chris | 0:fc0e38551beb | 259 | _spi.write(arg >> 0); |
| chris | 0:fc0e38551beb | 260 | _spi.write(0x95); |
| chris | 0:fc0e38551beb | 261 | |
| chris | 0:fc0e38551beb | 262 | // wait for the repsonse (response[7] == 0) |
| chris | 0:fc0e38551beb | 263 | for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { |
| chris | 0:fc0e38551beb | 264 | int response = _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 265 | if(!(response & 0x80)) { |
| chris | 0:fc0e38551beb | 266 | return response; |
| chris | 0:fc0e38551beb | 267 | } |
| chris | 0:fc0e38551beb | 268 | } |
| chris | 0:fc0e38551beb | 269 | _cs = 1; |
| chris | 0:fc0e38551beb | 270 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 271 | return -1; // timeout |
| chris | 0:fc0e38551beb | 272 | } |
| chris | 0:fc0e38551beb | 273 | |
| chris | 0:fc0e38551beb | 274 | |
| chris | 0:fc0e38551beb | 275 | int SDFileSystem::_cmd58() { |
| chris | 0:fc0e38551beb | 276 | _cs = 0; |
| chris | 0:fc0e38551beb | 277 | int arg = 0; |
| chris | 0:fc0e38551beb | 278 | |
| chris | 0:fc0e38551beb | 279 | // send a command |
| chris | 0:fc0e38551beb | 280 | _spi.write(0x40 | 58); |
| chris | 0:fc0e38551beb | 281 | _spi.write(arg >> 24); |
| chris | 0:fc0e38551beb | 282 | _spi.write(arg >> 16); |
| chris | 0:fc0e38551beb | 283 | _spi.write(arg >> 8); |
| chris | 0:fc0e38551beb | 284 | _spi.write(arg >> 0); |
| chris | 0:fc0e38551beb | 285 | _spi.write(0x95); |
| chris | 0:fc0e38551beb | 286 | |
| chris | 0:fc0e38551beb | 287 | // wait for the repsonse (response[7] == 0) |
| chris | 0:fc0e38551beb | 288 | for(int i=0; i<SD_COMMAND_TIMEOUT; i++) { |
| chris | 0:fc0e38551beb | 289 | int response = _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 290 | if(!(response & 0x80)) { |
| chris | 0:fc0e38551beb | 291 | int ocr = _spi.write(0xFF) << 24; |
| chris | 0:fc0e38551beb | 292 | ocr |= _spi.write(0xFF) << 16; |
| chris | 0:fc0e38551beb | 293 | ocr |= _spi.write(0xFF) << 8; |
| chris | 0:fc0e38551beb | 294 | ocr |= _spi.write(0xFF) << 0; |
| chris | 0:fc0e38551beb | 295 | // printf("OCR = 0x%08X\n", ocr); |
| chris | 0:fc0e38551beb | 296 | _cs = 1; |
| chris | 0:fc0e38551beb | 297 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 298 | return response; |
| chris | 0:fc0e38551beb | 299 | } |
| chris | 0:fc0e38551beb | 300 | } |
| chris | 0:fc0e38551beb | 301 | _cs = 1; |
| chris | 0:fc0e38551beb | 302 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 303 | return -1; // timeout |
| chris | 0:fc0e38551beb | 304 | } |
| chris | 0:fc0e38551beb | 305 | |
| chris | 0:fc0e38551beb | 306 | int SDFileSystem::_cmd8() { |
| chris | 0:fc0e38551beb | 307 | _cs = 0; |
| chris | 0:fc0e38551beb | 308 | |
| chris | 0:fc0e38551beb | 309 | // send a command |
| chris | 0:fc0e38551beb | 310 | _spi.write(0x40 | 8); // CMD8 |
| chris | 0:fc0e38551beb | 311 | _spi.write(0x00); // reserved |
| chris | 0:fc0e38551beb | 312 | _spi.write(0x00); // reserved |
| chris | 0:fc0e38551beb | 313 | _spi.write(0x01); // 3.3v |
| chris | 0:fc0e38551beb | 314 | _spi.write(0xAA); // check pattern |
| chris | 0:fc0e38551beb | 315 | _spi.write(0x87); // crc |
| chris | 0:fc0e38551beb | 316 | |
| chris | 0:fc0e38551beb | 317 | // wait for the repsonse (response[7] == 0) |
| chris | 0:fc0e38551beb | 318 | for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) { |
| chris | 0:fc0e38551beb | 319 | char response[5]; |
| chris | 0:fc0e38551beb | 320 | response[0] = _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 321 | if(!(response[0] & 0x80)) { |
| chris | 0:fc0e38551beb | 322 | for(int j=1; j<5; j++) { |
| chris | 0:fc0e38551beb | 323 | response[i] = _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 324 | } |
| chris | 0:fc0e38551beb | 325 | _cs = 1; |
| chris | 0:fc0e38551beb | 326 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 327 | return response[0]; |
| chris | 0:fc0e38551beb | 328 | } |
| chris | 0:fc0e38551beb | 329 | } |
| chris | 0:fc0e38551beb | 330 | _cs = 1; |
| chris | 0:fc0e38551beb | 331 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 332 | return -1; // timeout |
| chris | 0:fc0e38551beb | 333 | } |
| chris | 0:fc0e38551beb | 334 | |
| chris | 0:fc0e38551beb | 335 | int SDFileSystem::_read(char *buffer, int length) { |
| chris | 0:fc0e38551beb | 336 | _cs = 0; |
| chris | 0:fc0e38551beb | 337 | |
| chris | 0:fc0e38551beb | 338 | // read until start byte (0xFF) |
| chris | 0:fc0e38551beb | 339 | while(_spi.write(0xFF) != 0xFE); |
| chris | 0:fc0e38551beb | 340 | |
| chris | 0:fc0e38551beb | 341 | // read data |
| chris | 0:fc0e38551beb | 342 | for(int i=0; i<length; i++) { |
| chris | 0:fc0e38551beb | 343 | buffer[i] = _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 344 | } |
| chris | 0:fc0e38551beb | 345 | _spi.write(0xFF); // checksum |
| chris | 0:fc0e38551beb | 346 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 347 | |
| chris | 0:fc0e38551beb | 348 | _cs = 1; |
| chris | 0:fc0e38551beb | 349 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 350 | return 0; |
| chris | 0:fc0e38551beb | 351 | } |
| chris | 0:fc0e38551beb | 352 | |
| chris | 0:fc0e38551beb | 353 | int SDFileSystem::_write(const char *buffer, int length) { |
| chris | 0:fc0e38551beb | 354 | _cs = 0; |
| chris | 0:fc0e38551beb | 355 | |
| chris | 0:fc0e38551beb | 356 | // indicate start of block |
| chris | 0:fc0e38551beb | 357 | _spi.write(0xFE); |
| chris | 0:fc0e38551beb | 358 | |
| chris | 0:fc0e38551beb | 359 | // write the data |
| chris | 0:fc0e38551beb | 360 | for(int i=0; i<length; i++) { |
| chris | 0:fc0e38551beb | 361 | _spi.write(buffer[i]); |
| chris | 0:fc0e38551beb | 362 | } |
| chris | 0:fc0e38551beb | 363 | |
| chris | 0:fc0e38551beb | 364 | // write the checksum |
| chris | 0:fc0e38551beb | 365 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 366 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 367 | |
| chris | 0:fc0e38551beb | 368 | // check the repsonse token |
| chris | 0:fc0e38551beb | 369 | if((_spi.write(0xFF) & 0x1F) != 0x05) { |
| chris | 0:fc0e38551beb | 370 | _cs = 1; |
| chris | 0:fc0e38551beb | 371 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 372 | return 1; |
| chris | 0:fc0e38551beb | 373 | } |
| chris | 0:fc0e38551beb | 374 | |
| chris | 0:fc0e38551beb | 375 | // wait for write to finish |
| chris | 0:fc0e38551beb | 376 | while(_spi.write(0xFF) == 0); |
| chris | 0:fc0e38551beb | 377 | |
| chris | 0:fc0e38551beb | 378 | _cs = 1; |
| chris | 0:fc0e38551beb | 379 | _spi.write(0xFF); |
| chris | 0:fc0e38551beb | 380 | return 0; |
| chris | 0:fc0e38551beb | 381 | } |
| chris | 0:fc0e38551beb | 382 | |
| chris | 0:fc0e38551beb | 383 | static int ext_bits(char *data, int msb, int lsb) { |
| chris | 0:fc0e38551beb | 384 | int bits = 0; |
| chris | 0:fc0e38551beb | 385 | int size = 1 + msb - lsb; |
| chris | 0:fc0e38551beb | 386 | for(int i=0; i<size; i++) { |
| chris | 0:fc0e38551beb | 387 | int position = lsb + i; |
| chris | 0:fc0e38551beb | 388 | int byte = 15 - (position >> 3); |
| chris | 0:fc0e38551beb | 389 | int bit = position & 0x7; |
| chris | 0:fc0e38551beb | 390 | int value = (data[byte] >> bit) & 1; |
| chris | 0:fc0e38551beb | 391 | bits |= value << i; |
| chris | 0:fc0e38551beb | 392 | } |
| chris | 0:fc0e38551beb | 393 | return bits; |
| chris | 0:fc0e38551beb | 394 | } |
| chris | 0:fc0e38551beb | 395 | |
| chris | 0:fc0e38551beb | 396 | int SDFileSystem::_sd_sectors() { |
| chris | 0:fc0e38551beb | 397 | |
| chris | 0:fc0e38551beb | 398 | // CMD9, Response R2 (R1 byte + 16-byte block read) |
| chris | 0:fc0e38551beb | 399 | if(_cmdx(9, 0) != 0) { |
| chris | 0:fc0e38551beb | 400 | fprintf(stderr, "Didn't get a response from the disk\n"); |
| chris | 0:fc0e38551beb | 401 | return 0; |
| chris | 0:fc0e38551beb | 402 | } |
| chris | 0:fc0e38551beb | 403 | |
| chris | 0:fc0e38551beb | 404 | char csd[16]; |
| chris | 0:fc0e38551beb | 405 | if(_read(csd, 16) != 0) { |
| chris | 0:fc0e38551beb | 406 | fprintf(stderr, "Couldn't read csd response from disk\n"); |
| chris | 0:fc0e38551beb | 407 | return 0; |
| chris | 0:fc0e38551beb | 408 | } |
| chris | 0:fc0e38551beb | 409 | |
| chris | 0:fc0e38551beb | 410 | // csd_structure : csd[127:126] |
| chris | 0:fc0e38551beb | 411 | // c_size : csd[73:62] |
| chris | 0:fc0e38551beb | 412 | // c_size_mult : csd[49:47] |
| chris | 0:fc0e38551beb | 413 | // read_bl_len : csd[83:80] - the *maximum* read block length |
| chris | 0:fc0e38551beb | 414 | |
| chris | 0:fc0e38551beb | 415 | int csd_structure = ext_bits(csd, 127, 126); |
| chris | 0:fc0e38551beb | 416 | int c_size = ext_bits(csd, 73, 62); |
| chris | 0:fc0e38551beb | 417 | int c_size_mult = ext_bits(csd, 49, 47); |
| chris | 0:fc0e38551beb | 418 | int read_bl_len = ext_bits(csd, 83, 80); |
| chris | 0:fc0e38551beb | 419 | |
| chris | 0:fc0e38551beb | 420 | // printf("CSD_STRUCT = %d\n", csd_structure); |
| chris | 0:fc0e38551beb | 421 | |
| chris | 0:fc0e38551beb | 422 | if(csd_structure != 0) { |
| chris | 0:fc0e38551beb | 423 | fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n"); |
| chris | 0:fc0e38551beb | 424 | return 0; |
| chris | 0:fc0e38551beb | 425 | } |
| chris | 0:fc0e38551beb | 426 | |
| chris | 0:fc0e38551beb | 427 | // memory capacity = BLOCKNR * BLOCK_LEN |
| chris | 0:fc0e38551beb | 428 | // where |
| chris | 0:fc0e38551beb | 429 | // BLOCKNR = (C_SIZE+1) * MULT |
| chris | 0:fc0e38551beb | 430 | // MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8) |
| chris | 0:fc0e38551beb | 431 | // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12) |
| chris | 0:fc0e38551beb | 432 | |
| chris | 0:fc0e38551beb | 433 | int block_len = 1 << read_bl_len; |
| chris | 0:fc0e38551beb | 434 | int mult = 1 << (c_size_mult + 2); |
| chris | 0:fc0e38551beb | 435 | int blocknr = (c_size + 1) * mult; |
| chris | 0:fc0e38551beb | 436 | int capacity = blocknr * block_len; |
| chris | 0:fc0e38551beb | 437 | |
| chris | 0:fc0e38551beb | 438 | int blocks = capacity / 512; |
| chris | 0:fc0e38551beb | 439 | |
| chris | 0:fc0e38551beb | 440 | return blocks; |
| chris | 0:fc0e38551beb | 441 | } |