David Wilson
SD Card test
Embed:
(wiki syntax)
Show/hide line numbers
SDFileSystem.cpp
00001 /* mbed Microcontroller Library - SDFileSystem 00002 * Copyright (c) 2008-2009, sford 00003 */ 00004 00005 // VERY DRAFT CODE! Needs serious rework/refactoring 00006 00007 /* Introduction 00008 * ------------ 00009 * SD and MMC cards support a number of interfaces, but common to them all 00010 * is one based on SPI. This is the one I'm implmenting because it means 00011 * it is much more portable even though not so performant, and we already 00012 * have the mbed SPI Interface! 00013 * 00014 * The main reference I'm using is Chapter 7, "SPI Mode" of: 00015 * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf 00016 * 00017 * SPI Startup 00018 * ----------- 00019 * The SD card powers up in SD mode. The SPI interface mode is selected by 00020 * asserting CS low and sending the reset command (CMD0). The card will 00021 * respond with a (R1) response. 00022 * 00023 * CMD8 is optionally sent to determine the voltage range supported, and 00024 * indirectly determine whether it is a version 1.x SD/non-SD card or 00025 * version 2.x. I'll just ignore this for now. 00026 * 00027 * ACMD41 is repeatedly issued to initialise the card, until "in idle" 00028 * (bit 0) of the R1 response goes to '0', indicating it is initialised. 00029 * 00030 * You should also indicate whether the host supports High Capicity cards, 00031 * and check whether the card is high capacity - i'll also ignore this 00032 * 00033 * SPI Protocol 00034 * ------------ 00035 * The SD SPI protocol is based on transactions made up of 8-bit words, with 00036 * the host starting every bus transaction by asserting the CS signal low. The 00037 * card always responds to commands, data blocks and errors. 00038 * 00039 * The protocol supports a CRC, but by default it is off (except for the 00040 * first reset CMD0, where the CRC can just be pre-calculated, and CMD8) 00041 * I'll leave the CRC off I think! 00042 * 00043 * Standard capacity cards have variable data block sizes, whereas High 00044 * Capacity cards fix the size of data block to 512 bytes. I'll therefore 00045 * just always use the Standard Capacity cards with a block size of 512 bytes. 00046 * This is set with CMD16. 00047 * 00048 * You can read and write single blocks (CMD17, CMD25) or multiple blocks 00049 * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When 00050 * the card gets a read command, it responds with a response token, and then 00051 * a data token or an error. 00052 * 00053 * SPI Command Format 00054 * ------------------ 00055 * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC. 00056 * 00057 * +---------------+------------+------------+-----------+----------+--------------+ 00058 * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 | 00059 * +---------------+------------+------------+-----------+----------+--------------+ 00060 * 00061 * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95) 00062 * 00063 * All Application Specific commands shall be preceded with APP_CMD (CMD55). 00064 * 00065 * SPI Response Format 00066 * ------------------- 00067 * The main response format (R1) is a status byte (normally zero). Key flags: 00068 * idle - 1 if the card is in an idle state/initialising 00069 * cmd - 1 if an illegal command code was detected 00070 * 00071 * +-------------------------------------------------+ 00072 * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle | 00073 * +-------------------------------------------------+ 00074 * 00075 * R1b is the same, except it is followed by a busy signal (zeros) until 00076 * the first non-zero byte when it is ready again. 00077 * 00078 * Data Response Token 00079 * ------------------- 00080 * Every data block written to the card is acknowledged by a byte 00081 * response token 00082 * 00083 * +----------------------+ 00084 * | xxx | 0 | status | 1 | 00085 * +----------------------+ 00086 * 010 - OK! 00087 * 101 - CRC Error 00088 * 110 - Write Error 00089 * 00090 * Single Block Read and Write 00091 * --------------------------- 00092 * 00093 * Block transfers have a byte header, followed by the data, followed 00094 * by a 16-bit CRC. In our case, the data will always be 512 bytes. 00095 * 00096 * +------+---------+---------+- - - -+---------+-----------+----------+ 00097 * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] | 00098 * +------+---------+---------+- - - -+---------+-----------+----------+ 00099 */ 00100 00101 #include "SDFileSystem.h" 00102 00103 #define SD_COMMAND_TIMEOUT 500000 00104 00105 SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) : 00106 FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) { 00107 _cs = 1; 00108 } 00109 00110 #define R1_IDLE_STATE (1 << 0) 00111 #define R1_ERASE_RESET (1 << 1) 00112 #define R1_ILLEGAL_COMMAND (1 << 2) 00113 #define R1_COM_CRC_ERROR (1 << 3) 00114 #define R1_ERASE_SEQUENCE_ERROR (1 << 4) 00115 #define R1_ADDRESS_ERROR (1 << 5) 00116 #define R1_PARAMETER_ERROR (1 << 6) 00117 00118 // Types 00119 // - v1.x Standard Capacity 00120 // - v2.x Standard Capacity 00121 // - v2.x High Capacity 00122 // - Not recognised as an SD Card 00123 00124 #define SDCARD_FAIL 0 00125 #define SDCARD_V1 1 00126 #define SDCARD_V2 2 00127 #define SDCARD_V2HC 3 00128 00129 int SDFileSystem::initialise_card() { 00130 fprintf(stderr, "\r\ninitialise_card\r\n"); 00131 // Set to 100kHz for initialisation, and clock card with cs = 1 00132 _spi.frequency(100000); 00133 _cs = 1; 00134 for (int i=0; i<16; i++) { 00135 _spi.write(0xFF); 00136 } 00137 00138 // send CMD0, should return with all zeros except IDLE STATE set (bit 0) 00139 if (_cmd(0, 0) != R1_IDLE_STATE) { 00140 fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n"); 00141 return SDCARD_FAIL; 00142 } 00143 00144 // send CMD8 to determine whther it is ver 2.x 00145 int r = _cmd8(); 00146 if (r == R1_IDLE_STATE) { 00147 return initialise_card_v2(); 00148 } else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) { 00149 return initialise_card_v1(); 00150 } else { 00151 fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n"); 00152 return SDCARD_FAIL; 00153 } 00154 } 00155 00156 int SDFileSystem::initialise_card_v1() { 00157 for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { 00158 _cmd(55, 0); 00159 if (_cmd(41, 0) == 0) { 00160 return SDCARD_V1; 00161 } 00162 } 00163 00164 fprintf(stderr, "Timeout waiting for v1.x card\n"); 00165 return SDCARD_FAIL; 00166 } 00167 00168 int SDFileSystem::initialise_card_v2() { 00169 fprintf(stderr, "\r\ninitialise_card_v2\r\n"); 00170 for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { 00171 _cmd(55, 0); 00172 // if(_cmd(41, 0) == 0) { 00173 if (_cmd41() == 0) { 00174 fprintf(stderr, "\r\ncmd41 returns idle - now initialised. Send cmd58\r\n"); 00175 _cmd58(); 00176 return SDCARD_V2; 00177 } 00178 } 00179 00180 fprintf(stderr, "Timeout waiting for v2.x card\r\n"); 00181 return SDCARD_FAIL; 00182 } 00183 00184 int SDFileSystem::disk_initialize() { 00185 00186 int i = initialise_card(); 00187 printf("init card = %d\r\n", i); 00188 // printf("OK\n"); 00189 00190 _sectors = _sd_sectors(); 00191 00192 // Set block length to 512 (CMD16) 00193 if (_cmd(16, 512) != 0) { 00194 fprintf(stderr, "Set 512-byte block timed out\r\n"); 00195 return 1; 00196 } 00197 00198 _spi.frequency(1000000); // Set to 1MHz for data transfer 00199 return 0; 00200 } 00201 00202 int SDFileSystem::disk_write(const char *buffer, int block_number) { 00203 // set write address for single block (CMD24) 00204 if (_cmd(24, block_number * 512) != 0) { 00205 return 1; 00206 } 00207 00208 // send the data block 00209 _write(buffer, 512); 00210 return 0; 00211 } 00212 00213 int SDFileSystem::disk_read(char *buffer, int block_number) { 00214 // set read address for single block (CMD17) 00215 if (_cmd(17, block_number * 512) != 0) { 00216 return 1; 00217 } 00218 00219 // receive the data 00220 _read(buffer, 512); 00221 return 0; 00222 } 00223 00224 int SDFileSystem::disk_status() { 00225 return 0; 00226 } 00227 int SDFileSystem::disk_sync() { 00228 return 0; 00229 } 00230 int SDFileSystem::disk_sectors() { 00231 return _sectors; 00232 } 00233 00234 // PRIVATE FUNCTIONS 00235 00236 int SDFileSystem::_cmd(int cmd, int arg) { 00237 _cs = 0; 00238 00239 // send a command 00240 _spi.write(0x40 | cmd); 00241 _spi.write(arg >> 24); 00242 _spi.write(arg >> 16); 00243 _spi.write(arg >> 8); 00244 _spi.write(arg >> 0); 00245 _spi.write(0x95); 00246 00247 // wait for the repsonse (response[7] == 0) 00248 for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { 00249 int response = _spi.write(0xFF); 00250 if (!(response & 0x80)) { 00251 _cs = 1; 00252 _spi.write(0xFF); 00253 return response; 00254 } 00255 } 00256 _cs = 1; 00257 _spi.write(0xFF); 00258 return -1; // timeout 00259 } 00260 int SDFileSystem::_cmdx(int cmd, int arg) { 00261 _cs = 0; 00262 00263 // send a command 00264 _spi.write(0x40 | cmd); 00265 _spi.write(arg >> 24); 00266 _spi.write(arg >> 16); 00267 _spi.write(arg >> 8); 00268 _spi.write(arg >> 0); 00269 _spi.write(0x95); 00270 00271 // wait for the repsonse (response[7] == 0) 00272 for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { 00273 int response = _spi.write(0xFF); 00274 if (!(response & 0x80)) { 00275 return response; 00276 } 00277 } 00278 _cs = 1; 00279 _spi.write(0xFF); 00280 return -1; // timeout 00281 } 00282 00283 int SDFileSystem::_cmd41() { 00284 fprintf(stderr, "Issuing cmd41\r\n"); 00285 00286 _cs = 0; 00287 int arg = 0; 00288 00289 // send a command 00290 _spi.write(0x40 | 41); 00291 _spi.write(arg >> 24); 00292 _spi.write(arg >> 16); 00293 _spi.write(arg >> 8); 00294 _spi.write(arg >> 0); 00295 _spi.write(0x95); 00296 00297 union 00298 { 00299 unsigned int v; // register value 00300 struct CSD_REGISTER f; // register fields 00301 } csd; 00302 00303 int i; 00304 for (i=0; i<SD_COMMAND_TIMEOUT; i++) { 00305 int response = _spi.write(0xFF); 00306 fprintf(stderr, "cmd41 response=0x%08X\r\n", response); 00307 if (!(response & 0x80)) { 00308 csd.v = _spi.write(0xFF) << 24; 00309 csd.v |= _spi.write(0xFF) << 16; 00310 csd.v |= _spi.write(0xFF) << 8; 00311 csd.v |= _spi.write(0xFF) << 0; 00312 // _spi.write(0xFF); 00313 00314 fprintf(stderr, "cmd41 ocr=0x%08X\r\n", csd); 00315 00316 int test = csd.v; 00317 if (test & (1UL << 31)) 00318 fprintf(stderr, "Bit 31 = ON - Therefore - Card Powered up csd=0x%08X\r\n", csd); 00319 00320 // card_power_up_http://www.cs.cf.ac.uk/Dave/C/node13.html 00321 // if (csd_reg->card_power_up_status == 1) { 00322 if (csd.f.card_power_up_status == 1) { 00323 fprintf(stderr, "Card Powered up\r\n"); 00324 00325 if (csd.f.card_capacity_status == 1) { 00326 fprintf(stderr, "High Capacity Card\r\n"); 00327 } 00328 00329 _cs = 1; 00330 _spi.write(0xFF); 00331 return 0; 00332 } 00333 } 00334 } 00335 _cs = 1; 00336 _spi.write(0xFF); 00337 fprintf(stderr, "cmd41 timeout - exit with -1 i=%d, csd=0x%08X\r\n", i, csd); 00338 return -1; // timeout 00339 } 00340 00341 int SDFileSystem::_cmd58() { 00342 _cs = 0; 00343 int arg = 0; 00344 00345 // send a command 00346 _spi.write(0x40 | 58); 00347 _spi.write(arg >> 24); 00348 _spi.write(arg >> 16); 00349 _spi.write(arg >> 8); 00350 _spi.write(arg >> 0); 00351 _spi.write(0x95); 00352 00353 // wait for the repsonse (response[7] == 0) 00354 for (int i=0; i<SD_COMMAND_TIMEOUT; i++) { 00355 int response = _spi.write(0xFF); 00356 if (!(response & 0x80)) { 00357 int ocr = _spi.write(0xFF) << 24; 00358 ocr |= _spi.write(0xFF) << 16; 00359 ocr |= _spi.write(0xFF) << 8; 00360 ocr |= _spi.write(0xFF) << 0; 00361 // printf("OCR = 0x%08X\n", ocr); 00362 _cs = 1; 00363 _spi.write(0xFF); 00364 return response; 00365 } 00366 } 00367 _cs = 1; 00368 _spi.write(0xFF); 00369 return -1; // timeout 00370 } 00371 00372 int SDFileSystem::_cmd8() { 00373 fprintf(stderr, "Issuing cmd8\r\n"); 00374 _cs = 0; 00375 00376 // send a command 00377 _spi.write(0x40 | 8); // CMD8 00378 _spi.write(0x00); // reserved 00379 _spi.write(0x00); // reserved 00380 _spi.write(0x01); // 3.3v 00381 _spi.write(0xAA); // check pattern 00382 _spi.write(0x87); // crc 00383 00384 // wait for the repsonse (response[7] == 0) 00385 for (int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) { 00386 char response[5]; 00387 response[0] = _spi.write(0xFF); 00388 if (!(response[0] & 0x80)) { 00389 for (int j=1; j<5; j++) { 00390 response[i] = _spi.write(0xFF); 00391 fprintf(stderr, " %x,", response[i]); 00392 } 00393 fprintf(stderr, "\r\n"); 00394 _cs = 1; 00395 _spi.write(0xFF); 00396 return response[0]; 00397 } 00398 } 00399 _cs = 1; 00400 _spi.write(0xFF); 00401 return -1; // timeout 00402 } 00403 00404 int SDFileSystem::_read(char *buffer, int length) { 00405 _cs = 0; 00406 00407 // read until start byte (0xFF) 00408 while (_spi.write(0xFF) != 0xFE); 00409 00410 // read data 00411 for (int i=0; i<length; i++) { 00412 buffer[i] = _spi.write(0xFF); 00413 } 00414 _spi.write(0xFF); // checksum 00415 _spi.write(0xFF); 00416 00417 _cs = 1; 00418 _spi.write(0xFF); 00419 return 0; 00420 } 00421 00422 int SDFileSystem::_write(const char *buffer, int length) { 00423 _cs = 0; 00424 00425 // indicate start of block 00426 _spi.write(0xFE); 00427 00428 // write the data 00429 for (int i=0; i<length; i++) { 00430 _spi.write(buffer[i]); 00431 } 00432 00433 // write the checksum 00434 _spi.write(0xFF); 00435 _spi.write(0xFF); 00436 00437 // check the repsonse token 00438 if ((_spi.write(0xFF) & 0x1F) != 0x05) { 00439 _cs = 1; 00440 _spi.write(0xFF); 00441 return 1; 00442 } 00443 00444 // wait for write to finish 00445 while (_spi.write(0xFF) == 0); 00446 00447 _cs = 1; 00448 _spi.write(0xFF); 00449 return 0; 00450 } 00451 00452 static int ext_bits(char *data, int msb, int lsb) { 00453 int bits = 0; 00454 int size = 1 + msb - lsb; 00455 for (int i=0; i<size; i++) { 00456 int position = lsb + i; 00457 int byte = 15 - (position >> 3); 00458 int bit = position & 0x7; 00459 int value = (data[byte] >> bit) & 1; 00460 bits |= value << i; 00461 } 00462 return bits; 00463 } 00464 00465 int SDFileSystem::_sd_sectors() { 00466 00467 // CMD9, Response R2 (R1 byte + 16-byte block read) 00468 if (_cmdx(9, 0) != 0) { 00469 fprintf(stderr, "Didn't get a response from the disk\n"); 00470 return 0; 00471 } 00472 00473 char csd[16]; 00474 if (_read(csd, 16) != 0) { 00475 fprintf(stderr, "Couldn't read csd response from disk\n"); 00476 return 0; 00477 } 00478 00479 // csd_structure : csd[127:126] 00480 // c_size : csd[73:62] 00481 // c_size_mult : csd[49:47] 00482 // read_bl_len : csd[83:80] - the *maximum* read block length 00483 00484 int csd_structure = ext_bits(csd, 127, 126); 00485 int c_size = ext_bits(csd, 73, 62); 00486 int c_size_mult = ext_bits(csd, 49, 47); 00487 int read_bl_len = ext_bits(csd, 83, 80); 00488 00489 // printf("CSD_STRUCT = %d\n", csd_structure); 00490 00491 if (csd_structure != 0) { 00492 fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n"); 00493 return 0; 00494 } 00495 00496 // memory capacity = BLOCKNR * BLOCK_LEN 00497 // where 00498 // BLOCKNR = (C_SIZE+1) * MULT 00499 // MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8) 00500 // BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12) 00501 00502 int block_len = 1 << read_bl_len; 00503 int mult = 1 << (c_size_mult + 2); 00504 int blocknr = (c_size + 1) * mult; 00505 int capacity = blocknr * block_len; 00506 00507 int blocks = capacity / 512; 00508 00509 return blocks; 00510 }
Generated on Wed Jul 13 2022 03:35:30 by
1.7.2