SDCard.cpp

00001 /* mbed SDFileSystem Library, for providing file access to SD cards
00002  * Copyright (c) 2008-2010, sford
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
00020  * THE SOFTWARE.
00021  *
00022  *
00023  * This version significantly altered by Michael Moon and is (c) 2012
00024  */
00025 
00026 /* Introduction
00027  * ------------
00028  * SD and MMC cards support a number of interfaces, but common to them all
00029  * is one based on SPI. This is the one I'm implmenting because it means
00030  * it is much more portable even though not so performant, and we already
00031  * have the mbed SPI Interface!
00032  *
00033  * The main reference I'm using is Chapter 7, "SPI Mode" of:
00034  *  http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
00035  *
00036  * SPI Startup
00037  * -----------
00038  * The SD card powers up in SD mode. The SPI interface mode is selected by
00039  * asserting CS low and sending the reset command (CMD0). The card will
00040  * respond with a (R1) response.
00041  *
00042  * CMD8 is optionally sent to determine the voltage range supported, and
00043  * indirectly determine whether it is a version 1.x SD/non-SD card or
00044  * version 2.x. I'll just ignore this for now.
00045  *
00046  * ACMD41 is repeatedly issued to initialise the card, until "in idle"
00047  * (bit 0) of the R1 response goes to '0', indicating it is initialised.
00048  *
00049  * You should also indicate whether the host supports High Capicity cards,
00050  * and check whether the card is high capacity - i'll also ignore this
00051  *
00052  * SPI Protocol
00053  * ------------
00054  * The SD SPI protocol is based on transactions made up of 8-bit words, with
00055  * the host starting every bus transaction by asserting the CS signal low. The
00056  * card always responds to commands, data blocks and errors.
00057  *
00058  * The protocol supports a CRC, but by default it is off (except for the
00059  * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
00060  * I'll leave the CRC off I think!
00061  *
00062  * Standard capacity cards have variable data block sizes, whereas High
00063  * Capacity cards fix the size of data block to 512 bytes. I'll therefore
00064  * just always use the Standard Capacity cards with a block size of 512 bytes.
00065  * This is set with CMD16.
00066  *
00067  * You can read and write single blocks (CMD17, CMD25) or multiple blocks
00068  * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
00069  * the card gets a read command, it responds with a response token, and then
00070  * a data token or an error.
00071  *
00072  * SPI Command Format
00073  * ------------------
00074  * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
00075  *
00076  * +---------------+------------+------------+-----------+----------+--------------+
00077  * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
00078  * +---------------+------------+------------+-----------+----------+--------------+
00079  *
00080  * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
00081  *
00082  * All Application Specific commands shall be preceded with APP_CMD (CMD55).
00083  *
00084  * SPI Response Format
00085  * -------------------
00086  * The main response format (R1) is a status byte (normally zero). Key flags:
00087  *  idle - 1 if the card is in an idle state/initialising
00088  *  cmd  - 1 if an illegal command code was detected
00089  *
00090  *    +-------------------------------------------------+
00091  * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
00092  *    +-------------------------------------------------+
00093  *
00094  * R1b is the same, except it is followed by a busy signal (zeros) until
00095  * the first non-zero byte when it is ready again.
00096  *
00097  * Data Response Token
00098  * -------------------
00099  * Every data block written to the card is acknowledged by a byte
00100  * response token
00101  *
00102  * +----------------------+
00103  * | xxx | 0 | status | 1 |
00104  * +----------------------+
00105  *              010 - OK!
00106  *              101 - CRC Error
00107  *              110 - Write Error
00108  *
00109  * Single Block Read and Write
00110  * ---------------------------
00111  *
00112  * Block transfers have a byte header, followed by the data, followed
00113  * by a 16-bit CRC. In our case, the data will always be 512 bytes.
00114  *
00115  * +------+---------+---------+- -  - -+---------+-----------+----------+
00116  * | 0xFE | data[0] | data[1] |        | data[n] | crc[15:8] | crc[7:0] |
00117  * +------+---------+---------+- -  - -+---------+-----------+----------+
00118  */
00119 
00120 #include <stdio.h>
00121 #include <stdlib.h>
00122 
00123 #include "SDCard.h"
00124 
00125 static const uint8_t OXFF = 0xFF;
00126 
00127 #define SD_COMMAND_TIMEOUT 5000
00128 
00129 SDCard::SDCard(PinName mosi, PinName miso, PinName sclk, PinName cs) :
00130   _spi(mosi, miso, sclk), _cs(cs) {
00131     _cs.output();
00132     _cs = 1;
00133     busyflag = false;
00134     _sectors = 0;
00135 }
00136 
00137 #define R1_IDLE_STATE           (1 << 0)
00138 #define R1_ERASE_RESET          (1 << 1)
00139 #define R1_ILLEGAL_COMMAND      (1 << 2)
00140 #define R1_COM_CRC_ERROR        (1 << 3)
00141 #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
00142 #define R1_ADDRESS_ERROR        (1 << 5)
00143 #define R1_PARAMETER_ERROR      (1 << 6)
00144 
00145 // Types
00146 //  - v1.x Standard Capacity
00147 //  - v2.x Standard Capacity
00148 //  - v2.x High Capacity
00149 //  - Not recognised as an SD Card
00150 
00151 // #define SDCARD_FAIL 0
00152 // #define SDCARD_V1   1
00153 // #define SDCARD_V2   2
00154 // #define SDCARD_V2HC 3
00155 
00156 #define BUSY_FLAG_MULTIREAD          1
00157 #define BUSY_FLAG_MULTIWRITE         2
00158 #define BUSY_FLAG_ENDREAD            4
00159 #define BUSY_FLAG_ENDWRITE           8
00160 #define BUSY_FLAG_WAITNOTBUSY       (1<<31)
00161 
00162 #define SDCMD_GO_IDLE_STATE          0
00163 #define SDCMD_ALL_SEND_CID           2
00164 #define SDCMD_SEND_RELATIVE_ADDR     3
00165 #define SDCMD_SET_DSR                4
00166 #define SDCMD_SELECT_CARD            7
00167 #define SDCMD_SEND_IF_COND           8
00168 #define SDCMD_SEND_CSD               9
00169 #define SDCMD_SEND_CID              10
00170 #define SDCMD_STOP_TRANSMISSION     12
00171 #define SDCMD_SEND_STATUS           13
00172 #define SDCMD_GO_INACTIVE_STATE     15
00173 #define SDCMD_SET_BLOCKLEN          16
00174 #define SDCMD_READ_SINGLE_BLOCK     17
00175 #define SDCMD_READ_MULTIPLE_BLOCK   18
00176 #define SDCMD_WRITE_BLOCK           24
00177 #define SDCMD_WRITE_MULTIPLE_BLOCK  25
00178 #define SDCMD_PROGRAM_CSD           27
00179 #define SDCMD_SET_WRITE_PROT        28
00180 #define SDCMD_CLR_WRITE_PROT        29
00181 #define SDCMD_SEND_WRITE_PROT       30
00182 #define SDCMD_ERASE_WR_BLOCK_START  32
00183 #define SDCMD_ERASE_WR_BLK_END      33
00184 #define SDCMD_ERASE                 38
00185 #define SDCMD_LOCK_UNLOCK           42
00186 #define SDCMD_APP_CMD               55
00187 #define SDCMD_GEN_CMD               56
00188 
00189 #define SD_ACMD_SET_BUS_WIDTH            6
00190 #define SD_ACMD_SD_STATUS               13
00191 #define SD_ACMD_SEND_NUM_WR_BLOCKS      22
00192 #define SD_ACMD_SET_WR_BLK_ERASE_COUNT  23
00193 #define SD_ACMD_SD_SEND_OP_COND         41
00194 #define SD_ACMD_SET_CLR_CARD_DETECT     42
00195 #define SD_ACMD_SEND_CSR                51
00196 
00197 #define SD_CARD_HIGH_CAPACITY           (1UL<<30)
00198 
00199 #define BLOCK2ADDR(block)   (((cardtype == SDCARD_V1) || (cardtype == SDCARD_V2))?(block << 9):((cardtype == SDCARD_V2HC)?(block):0))
00200 
00201 SDCard::CARD_TYPE SDCard::initialise_card() {
00202     // Set to 25kHz for initialisation, and clock card with cs = 1
00203     _spi.frequency(25000);
00204     _cs = 1;
00205 
00206     for(int i=0; i<24; i++) {
00207         _spi.write(0xFF);
00208     }
00209 
00210     // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
00211     if(_cmd(SDCMD_GO_IDLE_STATE, 0) != R1_IDLE_STATE) {
00212         fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
00213         return cardtype = SDCARD_FAIL;
00214     }
00215 
00216     // send CMD8 to determine whther it is ver 2.x
00217     int r = _cmd8();
00218     if(r == R1_IDLE_STATE) {
00219         return initialise_card_v2();
00220     } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
00221         return initialise_card_v1();
00222     } else {
00223         fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
00224         return cardtype = SDCARD_FAIL;
00225     }
00226 }
00227 
00228 SDCard::CARD_TYPE SDCard::initialise_card_v1() {
00229     for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
00230         _cmd(SDCMD_APP_CMD, 0);
00231         if(_cmd(SD_ACMD_SD_SEND_OP_COND, 0) == 0) {
00232             return cardtype = SDCARD_V1;
00233         }
00234     }
00235 
00236     fprintf(stderr, "Timeout waiting for v1.x card\n");
00237     return SDCARD_FAIL;
00238 }
00239 
00240 SDCard::CARD_TYPE SDCard::initialise_card_v2() {
00241 
00242     for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
00243         _cmd(SDCMD_APP_CMD, 0);
00244         if(_cmd(SD_ACMD_SD_SEND_OP_COND, SD_CARD_HIGH_CAPACITY) == 0) {
00245             uint32_t ocr;
00246             _cmd58(&ocr);
00247             if (ocr & SD_CARD_HIGH_CAPACITY)
00248                 return cardtype = SDCARD_V2HC;
00249             else
00250                 return cardtype = SDCARD_V2;
00251         }
00252     }
00253 
00254     fprintf(stderr, "Timeout waiting for v2.x card\n");
00255     return cardtype = SDCARD_FAIL;
00256 }
00257 
00258 int SDCard::disk_initialize()
00259 {
00260     busyflag = true;
00261 
00262     _sectors = 0;
00263 
00264     CARD_TYPE i = initialise_card();
00265 
00266     if (i == SDCARD_FAIL) {
00267         busyflag = false;
00268         return 1;
00269     }
00270 
00271     _sectors = _sd_sectors();
00272 
00273     // Set block length to 512 (CMD16)
00274     if(_cmd(SDCMD_SET_BLOCKLEN, 512) != 0) {
00275         fprintf(stderr, "Set 512-byte block timed out\n");
00276         busyflag = false;
00277         return 1;
00278     }
00279 
00280     _spi.frequency(2500000); // Set to 2.5MHz for data transfer
00281 
00282     busyflag = false;
00283 
00284     return 0;
00285 }
00286 
00287 int SDCard::disk_write(const char *buffer, uint32_t block_number)
00288 {
00289     if (busyflag)
00290         return 0;
00291 
00292     busyflag = true;
00293 
00294     if (cardtype == SDCARD_FAIL)
00295         return -1;
00296     // set write address for single block (CMD24)
00297     if(_cmd(SDCMD_WRITE_BLOCK, BLOCK2ADDR(block_number)) != 0) {
00298         return 1;
00299     }
00300 
00301     // send the data block
00302     _write(buffer, 512);
00303 
00304     busyflag = false;
00305 
00306     return 0;
00307 }
00308 
00309 int SDCard::disk_read(char *buffer, uint32_t block_number)
00310 {
00311     if (busyflag)
00312         return 0;
00313 
00314     busyflag = true;
00315 
00316     if (cardtype == SDCARD_FAIL)
00317         return -1;
00318     // set read address for single block (CMD17)
00319     if(_cmd(SDCMD_READ_SINGLE_BLOCK, BLOCK2ADDR(block_number)) != 0) {
00320         return 1;
00321     }
00322 
00323     // receive the data
00324     _read(buffer, 512);
00325 
00326     busyflag = false;
00327 
00328     return 0;
00329 }
00330 
00331 int SDCard::disk_status() { return (_sectors > 0)?0:1; }
00332 int SDCard::disk_sync() {
00333     // TODO: wait for DMA, wait for card not busy
00334     return 0;
00335 }
00336 uint32_t SDCard::disk_sectors() { return _sectors; }
00337 uint64_t SDCard::disk_size() { return ((uint64_t) _sectors) << 9; }
00338 uint32_t SDCard::disk_blocksize() { return (1<<9); }
00339 bool SDCard::disk_canDMA() { return false; }
00340 
00341 SDCard::CARD_TYPE SDCard::card_type()
00342 {
00343     return cardtype;
00344 }
00345 
00346 // PRIVATE FUNCTIONS
00347 
00348 int SDCard::_cmd(int cmd, uint32_t arg) {
00349     _cs = 0;
00350 
00351     // send a command
00352     _spi.write(0x40 | cmd);
00353     _spi.write(arg >> 24);
00354     _spi.write(arg >> 16);
00355     _spi.write(arg >> 8);
00356     _spi.write(arg >> 0);
00357     _spi.write(0x95);
00358 
00359     // wait for the repsonse (response[7] == 0)
00360     for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
00361         int response = _spi.write(0xFF);
00362         if(!(response & 0x80)) {
00363             _cs = 1;
00364             _spi.write(0xFF);
00365             return response;
00366         }
00367     }
00368     _cs = 1;
00369     _spi.write(0xFF);
00370     return -1; // timeout
00371 }
00372 int SDCard::_cmdx(int cmd, uint32_t arg) {
00373     _cs = 0;
00374 
00375     // send a command
00376     _spi.write(0x40 | cmd);
00377     _spi.write(arg >> 24);
00378     _spi.write(arg >> 16);
00379     _spi.write(arg >> 8);
00380     _spi.write(arg >> 0);
00381     _spi.write(0x95);
00382 
00383     // wait for the repsonse (response[7] == 0)
00384     for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
00385         int response = _spi.write(0xFF);
00386         if(!(response & 0x80)) {
00387             return response;
00388         }
00389     }
00390     _cs = 1;
00391     _spi.write(0xFF);
00392     return -1; // timeout
00393 }
00394 
00395 
00396 int SDCard::_cmd58(uint32_t *ocr) {
00397     _cs = 0;
00398     int arg = 0;
00399 
00400     // send a command
00401     _spi.write(0x40 | 58);
00402     _spi.write(arg >> 24);
00403     _spi.write(arg >> 16);
00404     _spi.write(arg >> 8);
00405     _spi.write(arg >> 0);
00406     _spi.write(0x95);
00407 
00408     // wait for the repsonse (response[7] == 0)
00409     for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
00410         int response = _spi.write(0xFF);
00411         if(!(response & 0x80)) {
00412             *ocr = _spi.write(0xFF) << 24;
00413             *ocr |= _spi.write(0xFF) << 16;
00414             *ocr |= _spi.write(0xFF) << 8;
00415             *ocr |= _spi.write(0xFF) << 0;
00416 //            printf("OCR = 0x%08X\n", ocr);
00417             _cs = 1;
00418             _spi.write(0xFF);
00419             return response;
00420         }
00421     }
00422     _cs = 1;
00423     _spi.write(0xFF);
00424     return -1; // timeout
00425 }
00426 
00427 int SDCard::_cmd8() {
00428     _cs = 0;
00429 
00430     // send a command
00431     _spi.write(0x40 | SDCMD_SEND_IF_COND); // CMD8
00432     _spi.write(0x00);     // reserved
00433     _spi.write(0x00);     // reserved
00434     _spi.write(0x01);     // 3.3v
00435     _spi.write(0xAA);     // check pattern
00436     _spi.write(0x87);     // crc
00437 
00438     // wait for the repsonse (response[7] == 0)
00439     for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
00440         char response[5];
00441         response[0] = _spi.write(0xFF);
00442         if(!(response[0] & 0x80)) {
00443                 for(int j=1; j<5; j++) {
00444                     response[i] = _spi.write(0xFF);
00445                 }
00446                 _cs = 1;
00447                 _spi.write(0xFF);
00448                 return response[0];
00449         }
00450     }
00451     _cs = 1;
00452     _spi.write(0xFF);
00453     return -1; // timeout
00454 }
00455 
00456 int SDCard::_read(char *buffer, int length) {
00457     _cs = 0;
00458 
00459     // read until start byte (0xFF)
00460     while(_spi.write(0xFF) != 0xFE);
00461 //     uint8_t r;
00462 //     while((r = _spi.write(0xFF)) != 0xFE)
00463 //     {
00464 //         iprintf("0x%02X ", r);
00465 //         for (volatile uint32_t j = 262144; j; j--);
00466 //     }
00467 //
00468 //     iprintf("Got start byte, reading data\n");
00469 
00470     // read data
00471     for(int i=0; i<length; i++) {
00472         buffer[i] = _spi.write(0xFF);
00473     }
00474     _spi.write(0xFF); // checksum
00475     _spi.write(0xFF);
00476 
00477     _cs = 1;
00478     _spi.write(0xFF);
00479     return 0;
00480 }
00481 
00482 int SDCard::_write(const char *buffer, int length) {
00483     _cs = 0;
00484 
00485     // indicate start of block
00486     _spi.write(0xFE);
00487 
00488     // write the data
00489     for(int i=0; i<length; i++) {
00490         _spi.write(buffer[i]);
00491     }
00492 
00493     // write the checksum
00494     _spi.write(0xFF);
00495     _spi.write(0xFF);
00496 
00497     // check the repsonse token
00498     if((_spi.write(0xFF) & 0x1F) != 0x05) {
00499         _cs = 1;
00500         _spi.write(0xFF);
00501         return 1;
00502     }
00503 
00504     // wait for write to finish
00505     while(_spi.write(0xFF) == 0);
00506 
00507     _cs = 1;
00508     _spi.write(0xFF);
00509     return 0;
00510 }
00511 
00512 static int ext_bits(char *data, int msb, int lsb) {
00513     int bits = 0;
00514     int size = 1 + msb - lsb;
00515     for(int i=0; i<size; i++) {
00516         int position = lsb + i;
00517         int byte = 15 - (position >> 3);
00518         int bit = position & 0x7;
00519         int value = (data[byte] >> bit) & 1;
00520         bits |= value << i;
00521     }
00522     return bits;
00523 }
00524 
00525 uint32_t SDCard::_sd_sectors() {
00526 
00527     // CMD9, Response R2 (R1 byte + 16-byte block read)
00528     if(_cmdx(SDCMD_SEND_CSD, 0) != 0) {
00529         fprintf(stderr, "Didn't get a response from the disk\n");
00530         return 0;
00531     }
00532 
00533     char csd[16];
00534     if(_read(csd, 16) != 0) {
00535         fprintf(stderr, "Couldn't read csd response from disk\n");
00536         return 0;
00537     }
00538 
00539     // csd_structure : csd[127:126]
00540     // c_size        : csd[73:62]
00541     // c_size_mult   : csd[49:47]
00542     // read_bl_len   : csd[83:80] - the *maximum* read block length
00543 
00544     int csd_structure = ext_bits(csd, 127, 126);
00545 
00546     if (csd_structure == 0)
00547     {
00548         if (cardtype == SDCARD_V2HC)
00549         {
00550             fprintf(stderr, "SDHC card with regular SD descriptor!\n");
00551             return 0;
00552         }
00553         uint32_t c_size = ext_bits(csd, 73, 62);
00554         uint32_t c_size_mult = ext_bits(csd, 49, 47);
00555         uint32_t read_bl_len = ext_bits(csd, 83, 80);
00556 
00557         uint32_t block_len = 1 << read_bl_len;
00558         uint32_t mult = 1 << (c_size_mult + 2);
00559         uint32_t blocknr = (c_size + 1) * mult;
00560 
00561         if (block_len >= 512)
00562             return blocknr * (block_len >> 9);
00563         else
00564             return (blocknr * block_len) >> 9;
00565     }
00566     else if (csd_structure == 1)
00567     {
00568         if (cardtype != SDCARD_V2HC)
00569         {
00570             fprintf(stderr, "SD V1 or V2 card with SDHC descriptor!\n");
00571             return 0;
00572         }
00573         uint32_t c_size = ext_bits(csd, 69, 48);
00574         uint32_t blocknr = (c_size + 1) * 1024;
00575 
00576         return blocknr;
00577     }
00578     fprintf(stderr, "This disk tastes funny! (%d) I only know about type 0 or 1 CSD structures\n", csd_structure);
00579     return 0;
00580 }
00581 
00582 bool SDCard::busy()
00583 {
00584     return busyflag;
00585 }