Not totally sure why this forked, but should be the same as the original SDFileSystem library
Fork of SDFileSystem by
SDFileSystem.cpp
00001 /* mbed Microcontroller Library 00002 * Copyright (c) 2006-2012 ARM Limited 00003 * 00004 * Permission is hereby granted, free of charge, to any person obtaining a copy 00005 * of this software and associated documentation files (the "Software"), to deal 00006 * in the Software without restriction, including without limitation the rights 00007 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 00008 * copies of the Software, and to permit persons to whom the Software is 00009 * furnished to do so, subject to the following conditions: 00010 * 00011 * The above copyright notice and this permission notice shall be included in 00012 * all copies or substantial portions of the Software. 00013 * 00014 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 00015 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 00016 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 00017 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 00018 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 00019 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 00020 * SOFTWARE. 00021 */ 00022 00023 /* Introduction 00024 * ------------ 00025 * SD and MMC cards support a number of interfaces, but common to them all 00026 * is one based on SPI. This is the one I'm implmenting because it means 00027 * it is much more portable even though not so performant, and we already 00028 * have the mbed SPI Interface! 00029 * 00030 * The main reference I'm using is Chapter 7, "SPI Mode" of: 00031 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf 00032 * 00033 * SPI Startup 00034 * ----------- 00035 * The SD card powers up in SD mode. The SPI interface mode is selected by 00036 * asserting CS low and sending the reset command (CMD0). The card will 00037 * respond with a (R1) response. 00038 * 00039 * CMD8 is optionally sent to determine the voltage range supported, and 00040 * indirectly determine whether it is a version 1.x SD/non-SD card or 00041 * version 2.x. I'll just ignore this for now. 00042 * 00043 * ACMD41 is repeatedly issued to initialise the card, until "in idle" 00044 * (bit 0) of the R1 response goes to '0', indicating it is initialised. 00045 * 00046 * You should also indicate whether the host supports High Capicity cards, 00047 * and check whether the card is high capacity - i'll also ignore this 00048 * 00049 * SPI Protocol 00050 * ------------ 00051 * The SD SPI protocol is based on transactions made up of 8-bit words, with 00052 * the host starting every bus transaction by asserting the CS signal low. The 00053 * card always responds to commands, data blocks and errors. 00054 * 00055 * The protocol supports a CRC, but by default it is off (except for the 00056 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8) 00057 * I'll leave the CRC off I think! 00058 * 00059 * Standard capacity cards have variable data block sizes, whereas High 00060 * Capacity cards fix the size of data block to 512 bytes. I'll therefore 00061 * just always use the Standard Capacity cards with a block size of 512 bytes. 00062 * This is set with CMD16. 00063 * 00064 * You can read and write single blocks (CMD17, CMD25) or multiple blocks 00065 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When 00066 * the card gets a read command, it responds with a response token, and then 00067 * a data token or an error. 00068 * 00069 * SPI Command Format 00070 * ------------------ 00071 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC. 00072 * 00073 * +---------------+------------+------------+-----------+----------+--------------+ 00074 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 | 00075 * +---------------+------------+------------+-----------+----------+--------------+ 00076 * 00077 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95) 00078 * 00079 * All Application Specific commands shall be preceded with APP_CMD (CMD55). 00080 * 00081 * SPI Response Format 00082 * ------------------- 00083 * The main response format (R1) is a status byte (normally zero). Key flags: 00084 * idle - 1 if the card is in an idle state/initialising 00085 * cmd - 1 if an illegal command code was detected 00086 * 00087 * +-------------------------------------------------+ 00088 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle | 00089 * +-------------------------------------------------+ 00090 * 00091 * R1b is the same, except it is followed by a busy signal (zeros) until 00092 * the first non-zero byte when it is ready again. 00093 * 00094 * Data Response Token 00095 * ------------------- 00096 * Every data block written to the card is acknowledged by a byte 00097 * response token 00098 * 00099 * +----------------------+ 00100 * | xxx | 0 | status | 1 | 00101 * +----------------------+ 00102 * 010 - OK! 00103 * 101 - CRC Error 00104 * 110 - Write Error 00105 * 00106 * Single Block Read and Write 00107 * --------------------------- 00108 * 00109 * Block transfers have a byte header, followed by the data, followed 00110 * by a 16-bit CRC. In our case, the data will always be 512 bytes. 00111 * 00112 * +------+---------+---------+- - - -+---------+-----------+----------+ 00113 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] | 00114 * +------+---------+---------+- - - -+---------+-----------+----------+ 00115 */ 00116 #include "SDFileSystem.h" 00117 #include "mbed_debug.h" 00118 00119 #define SD_COMMAND_TIMEOUT 5000 00120 00121 #define SD_DBG 0 00122 00123 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) : 00124 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) { 00125 _cs = 1; 00126 } 00127 00128 #define R1_IDLE_STATE (1 << 0) 00129 #define R1_ERASE_RESET (1 << 1) 00130 #define R1_ILLEGAL_COMMAND (1 << 2) 00131 #define R1_COM_CRC_ERROR (1 << 3) 00132 #define R1_ERASE_SEQUENCE_ERROR (1 << 4) 00133 #define R1_ADDRESS_ERROR (1 << 5) 00134 #define R1_PARAMETER_ERROR (1 << 6) 00135 00136 // Types 00137 #define SDCARD_FAIL 0 //!< v1.x Standard Capacity 00138 #define SDCARD_V1 1 //!< v2.x Standard Capacity 00139 #define SDCARD_V2 2 //!< v2.x High Capacity 00140 #define SDCARD_V2HC 3 //!< Not recognised as an SD Card 00141 00142 int SDFileSystem::initialise_card() { 00143 // Set to 100kHz for initialisation, and clock card with cs = 1 00144 _spi.frequency(100000); 00145 _cs = 1; 00146 for (int i = 0; i < 16; i++) { 00147 _spi.write(0xFF); 00148 } 00149 00150 // send CMD0, should return with all zeros except IDLE STATE set (bit 0) 00151 if (_cmd(0, 0) != R1_IDLE_STATE) { 00152 debug("No disk, or could not put SD card in to SPI idle state\n"); 00153 return SDCARD_FAIL; 00154 } 00155 00156 // send CMD8 to determine whther it is ver 2.x 00157 int r = _cmd8(); 00158 if (r == R1_IDLE_STATE) { 00159 return initialise_card_v2(); 00160 } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) { 00161 return initialise_card_v1(); 00162 } else { 00163 debug("Not in idle state after sending CMD8 (not an SD card?)\n"); 00164 return SDCARD_FAIL; 00165 } 00166 } 00167 00168 int SDFileSystem::initialise_card_v1() { 00169 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) { 00170 _cmd(55, 0); 00171 if (_cmd(41, 0) == 0) { 00172 cdv = 512; 00173 debug_if(SD_DBG, "\n\rInit: SEDCARD_V1\n\r"); 00174 return SDCARD_V1; 00175 } 00176 } 00177 00178 debug("Timeout waiting for v1.x card\n"); 00179 return SDCARD_FAIL; 00180 } 00181 00182 int SDFileSystem::initialise_card_v2() { 00183 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) { 00184 wait_ms(50); 00185 _cmd58(); 00186 _cmd(55, 0); 00187 if (_cmd(41, 0x40000000) == 0) { 00188 _cmd58(); 00189 debug_if(SD_DBG, "\n\rInit: SDCARD_V2\n\r"); 00190 cdv = 1; 00191 return SDCARD_V2; 00192 } 00193 } 00194 00195 debug("Timeout waiting for v2.x card\n"); 00196 return SDCARD_FAIL; 00197 } 00198 00199 int SDFileSystem::disk_initialize() { 00200 int i = initialise_card(); 00201 debug_if(SD_DBG, "init card = %d\n", i); 00202 _sectors = _sd_sectors(); 00203 00204 // Set block length to 512 (CMD16) 00205 if (_cmd(16, 512) != 0) { 00206 debug("Set 512-byte block timed out\n"); 00207 return 1; 00208 } 00209 00210 _spi.frequency(1000000); // Set to 1MHz for data transfer 00211 return 0; 00212 } 00213 00214 int SDFileSystem::disk_write(const uint8_t *buffer, uint64_t block_number, uint8_t count) { 00215 while (count--) { 00216 // set write address for single block (CMD24) 00217 if (_cmd(24, block_number * cdv) != 0) { 00218 return 1; 00219 } 00220 00221 // send the data block 00222 _write(buffer, 512); 00223 buffer+=512; 00224 block_number++; 00225 } 00226 return 0; 00227 } 00228 00229 int SDFileSystem::disk_read(uint8_t *buffer, uint64_t block_number,uint8_t count) { 00230 while (count--) { 00231 // set read address for single block (CMD17) 00232 if (_cmd(17, block_number * cdv) != 0) { 00233 return 1; 00234 } 00235 00236 // receive the data 00237 _read(buffer, 512); 00238 buffer+=512; 00239 block_number++; 00240 } 00241 return 0; 00242 } 00243 00244 int SDFileSystem::disk_status() { return 0; } 00245 int SDFileSystem::disk_sync() { return 0; } 00246 uint64_t SDFileSystem::disk_sectors() { return _sectors; } 00247 00248 00249 // PRIVATE FUNCTIONS 00250 int SDFileSystem::_cmd(int cmd, int arg) { 00251 _cs = 0; 00252 00253 // send a command 00254 _spi.write(0x40 | cmd); 00255 _spi.write(arg >> 24); 00256 _spi.write(arg >> 16); 00257 _spi.write(arg >> 8); 00258 _spi.write(arg >> 0); 00259 _spi.write(0x95); 00260 00261 // wait for the repsonse (response[7] == 0) 00262 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) { 00263 int response = _spi.write(0xFF); 00264 if (!(response & 0x80)) { 00265 _cs = 1; 00266 _spi.write(0xFF); 00267 return response; 00268 } 00269 } 00270 _cs = 1; 00271 _spi.write(0xFF); 00272 return -1; // timeout 00273 } 00274 int SDFileSystem::_cmdx(int cmd, int arg) { 00275 _cs = 0; 00276 00277 // send a command 00278 _spi.write(0x40 | cmd); 00279 _spi.write(arg >> 24); 00280 _spi.write(arg >> 16); 00281 _spi.write(arg >> 8); 00282 _spi.write(arg >> 0); 00283 _spi.write(0x95); 00284 00285 // wait for the repsonse (response[7] == 0) 00286 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) { 00287 int response = _spi.write(0xFF); 00288 if (!(response & 0x80)) { 00289 return response; 00290 } 00291 } 00292 _cs = 1; 00293 _spi.write(0xFF); 00294 return -1; // timeout 00295 } 00296 00297 00298 int SDFileSystem::_cmd58() { 00299 _cs = 0; 00300 int arg = 0; 00301 00302 // send a command 00303 _spi.write(0x40 | 58); 00304 _spi.write(arg >> 24); 00305 _spi.write(arg >> 16); 00306 _spi.write(arg >> 8); 00307 _spi.write(arg >> 0); 00308 _spi.write(0x95); 00309 00310 // wait for the repsonse (response[7] == 0) 00311 for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) { 00312 int response = _spi.write(0xFF); 00313 if (!(response & 0x80)) { 00314 int ocr = _spi.write(0xFF) << 24; 00315 ocr |= _spi.write(0xFF) << 16; 00316 ocr |= _spi.write(0xFF) << 8; 00317 ocr |= _spi.write(0xFF) << 0; 00318 _cs = 1; 00319 _spi.write(0xFF); 00320 return response; 00321 } 00322 } 00323 _cs = 1; 00324 _spi.write(0xFF); 00325 return -1; // timeout 00326 } 00327 00328 int SDFileSystem::_cmd8() { 00329 _cs = 0; 00330 00331 // send a command 00332 _spi.write(0x40 | 8); // CMD8 00333 _spi.write(0x00); // reserved 00334 _spi.write(0x00); // reserved 00335 _spi.write(0x01); // 3.3v 00336 _spi.write(0xAA); // check pattern 00337 _spi.write(0x87); // crc 00338 00339 // wait for the repsonse (response[7] == 0) 00340 for (int i = 0; i < SD_COMMAND_TIMEOUT * 1000; i++) { 00341 char response[5]; 00342 response[0] = _spi.write(0xFF); 00343 if (!(response[0] & 0x80)) { 00344 for (int j = 1; j < 5; j++) { 00345 response[i] = _spi.write(0xFF); 00346 } 00347 _cs = 1; 00348 _spi.write(0xFF); 00349 return response[0]; 00350 } 00351 } 00352 _cs = 1; 00353 _spi.write(0xFF); 00354 return -1; // timeout 00355 } 00356 00357 int SDFileSystem::_read(uint8_t *buffer, uint32_t length) { 00358 _cs = 0; 00359 00360 // read until start byte (0xFF) 00361 while (_spi.write(0xFF) != 0xFE); 00362 00363 // read data 00364 for (int i = 0; i < length; i++) { 00365 buffer[i] = _spi.write(0xFF); 00366 } 00367 _spi.write(0xFF); // checksum 00368 _spi.write(0xFF); 00369 00370 _cs = 1; 00371 _spi.write(0xFF); 00372 return 0; 00373 } 00374 00375 int SDFileSystem::_write(const uint8_t*buffer, uint32_t length) { 00376 _cs = 0; 00377 00378 // indicate start of block 00379 _spi.write(0xFE); 00380 00381 // write the data 00382 for (int i = 0; i < length; i++) { 00383 _spi.write(buffer[i]); 00384 } 00385 00386 // write the checksum 00387 _spi.write(0xFF); 00388 _spi.write(0xFF); 00389 00390 // check the response token 00391 if ((_spi.write(0xFF) & 0x1F) != 0x05) { 00392 _cs = 1; 00393 _spi.write(0xFF); 00394 return 1; 00395 } 00396 00397 // wait for write to finish 00398 while (_spi.write(0xFF) == 0); 00399 00400 _cs = 1; 00401 _spi.write(0xFF); 00402 return 0; 00403 } 00404 00405 static uint32_t ext_bits(unsigned char *data, int msb, int lsb) { 00406 uint32_t bits = 0; 00407 uint32_t size = 1 + msb - lsb; 00408 for (int i = 0; i < size; i++) { 00409 uint32_t position = lsb + i; 00410 uint32_t byte = 15 - (position >> 3); 00411 uint32_t bit = position & 0x7; 00412 uint32_t value = (data[byte] >> bit) & 1; 00413 bits |= value << i; 00414 } 00415 return bits; 00416 } 00417 00418 uint64_t SDFileSystem::_sd_sectors() { 00419 uint32_t c_size, c_size_mult, read_bl_len; 00420 uint32_t block_len, mult, blocknr, capacity; 00421 uint32_t hc_c_size; 00422 uint64_t blocks; 00423 00424 // CMD9, Response R2 (R1 byte + 16-byte block read) 00425 if (_cmdx(9, 0) != 0) { 00426 debug("Didn't get a response from the disk\n"); 00427 return 0; 00428 } 00429 00430 uint8_t csd[16]; 00431 if (_read(csd, 16) != 0) { 00432 debug("Couldn't read csd response from disk\n"); 00433 return 0; 00434 } 00435 00436 // csd_structure : csd[127:126] 00437 // c_size : csd[73:62] 00438 // c_size_mult : csd[49:47] 00439 // read_bl_len : csd[83:80] - the *maximum* read block length 00440 00441 int csd_structure = ext_bits(csd, 127, 126); 00442 00443 switch (csd_structure) { 00444 case 0: 00445 cdv = 512; 00446 c_size = ext_bits(csd, 73, 62); 00447 c_size_mult = ext_bits(csd, 49, 47); 00448 read_bl_len = ext_bits(csd, 83, 80); 00449 00450 block_len = 1 << read_bl_len; 00451 mult = 1 << (c_size_mult + 2); 00452 blocknr = (c_size + 1) * mult; 00453 capacity = blocknr * block_len; 00454 blocks = capacity / 512; 00455 debug_if(SD_DBG, "\n\rSDCard\n\rc_size: %d \n\rcapacity: %ld \n\rsectors: %lld\n\r", c_size, capacity, blocks); 00456 break; 00457 00458 case 1: 00459 cdv = 1; 00460 hc_c_size = ext_bits(csd, 63, 48); 00461 blocks = (hc_c_size+1)*1024; 00462 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); 00463 break; 00464 00465 default: 00466 debug("CSD struct unsupported\r\n"); 00467 return 0; 00468 }; 00469 return blocks; 00470 }
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