Diff: SDFileSystem.cpp

Revision:

1:9dcd70c32180

Parent:

0:1596b8644523

Child:

2:71b1999a8ea5

--- a/SDFileSystem.cpp	Mon Nov 19 04:44:11 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,441 +0,0 @@
-/* mbed Microcontroller Library - SDFileSystem
- * Copyright (c) 2008-2009, sford
- */
- 
-// VERY DRAFT CODE! Needs serious rework/refactoring 
- 
-/* Introduction
- * ------------
- * SD and MMC cards support a number of interfaces, but common to them all
- * is one based on SPI. This is the one I'm implmenting because it means
- * it is much more portable even though not so performant, and we already 
- * have the mbed SPI Interface!
- *
- * The main reference I'm using is Chapter 7, "SPI Mode" of: 
- *  http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
- *
- * SPI Startup
- * -----------
- * The SD card powers up in SD mode. The SPI interface mode is selected by
- * asserting CS low and sending the reset command (CMD0). The card will 
- * respond with a (R1) response.
- *
- * CMD8 is optionally sent to determine the voltage range supported, and 
- * indirectly determine whether it is a version 1.x SD/non-SD card or 
- * version 2.x. I'll just ignore this for now.
- *
- * ACMD41 is repeatedly issued to initialise the card, until "in idle"
- * (bit 0) of the R1 response goes to '0', indicating it is initialised.
- *
- * You should also indicate whether the host supports High Capicity cards,
- * and check whether the card is high capacity - i'll also ignore this
- *
- * SPI Protocol
- * ------------
- * The SD SPI protocol is based on transactions made up of 8-bit words, with
- * the host starting every bus transaction by asserting the CS signal low. The
- * card always responds to commands, data blocks and errors.
- * 
- * The protocol supports a CRC, but by default it is off (except for the 
- * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
- * I'll leave the CRC off I think! 
- * 
- * Standard capacity cards have variable data block sizes, whereas High 
- * Capacity cards fix the size of data block to 512 bytes. I'll therefore
- * just always use the Standard Capacity cards with a block size of 512 bytes.
- * This is set with CMD16.
- *
- * You can read and write single blocks (CMD17, CMD25) or multiple blocks 
- * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
- * the card gets a read command, it responds with a response token, and then 
- * a data token or an error.
- * 
- * SPI Command Format
- * ------------------
- * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
- *
- * +---------------+------------+------------+-----------+----------+--------------+
- * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
- * +---------------+------------+------------+-----------+----------+--------------+
- *
- * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
- *
- * All Application Specific commands shall be preceded with APP_CMD (CMD55).
- *
- * SPI Response Format
- * -------------------
- * The main response format (R1) is a status byte (normally zero). Key flags:
- *  idle - 1 if the card is in an idle state/initialising 
- *  cmd  - 1 if an illegal command code was detected
- *
- *    +-------------------------------------------------+
- * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
- *    +-------------------------------------------------+
- *
- * R1b is the same, except it is followed by a busy signal (zeros) until
- * the first non-zero byte when it is ready again.
- *
- * Data Response Token
- * -------------------
- * Every data block written to the card is acknowledged by a byte 
- * response token
- *
- * +----------------------+
- * | xxx | 0 | status | 1 |
- * +----------------------+
- *              010 - OK!
- *              101 - CRC Error
- *              110 - Write Error
- *
- * Single Block Read and Write
- * ---------------------------
- *
- * Block transfers have a byte header, followed by the data, followed
- * by a 16-bit CRC. In our case, the data will always be 512 bytes.
- *  
- * +------+---------+---------+- -  - -+---------+-----------+----------+
- * | 0xFE | data[0] | data[1] |        | data[n] | crc[15:8] | crc[7:0] | 
- * +------+---------+---------+- -  - -+---------+-----------+----------+
- */
- 
-#include "SDFileSystem.h"
-
-#define SD_COMMAND_TIMEOUT 5000
-
-SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
-  FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
-      _cs = 1; 
-}
-
-#define R1_IDLE_STATE           (1 << 0)
-#define R1_ERASE_RESET          (1 << 1)
-#define R1_ILLEGAL_COMMAND      (1 << 2)
-#define R1_COM_CRC_ERROR        (1 << 3)
-#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
-#define R1_ADDRESS_ERROR        (1 << 5)
-#define R1_PARAMETER_ERROR      (1 << 6)
-
-// Types
-//  - v1.x Standard Capacity
-//  - v2.x Standard Capacity
-//  - v2.x High Capacity
-//  - Not recognised as an SD Card
-
-#define SDCARD_FAIL 0
-#define SDCARD_V1   1
-#define SDCARD_V2   2
-#define SDCARD_V2HC 3
-
-int SDFileSystem::initialise_card() {
-    // Set to 100kHz for initialisation, and clock card with cs = 1
-    _spi.frequency(100000); 
-    _cs = 1;
-    for(int i=0; i<16; i++) {   
-        _spi.write(0xFF);
-    }
-
-    // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
-    if(_cmd(0, 0) != R1_IDLE_STATE) { 
-        fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
-        return SDCARD_FAIL;
-    }
-
-    // send CMD8 to determine whther it is ver 2.x
-    int r = _cmd8();
-    if(r == R1_IDLE_STATE) {
-        return initialise_card_v2();
-    } else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
-        return initialise_card_v1();
-    } else {
-        fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
-        return SDCARD_FAIL;
-    }
-}
-
-int SDFileSystem::initialise_card_v1() {
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        _cmd(55, 0); 
-        if(_cmd(41, 0) == 0) { 
-            return SDCARD_V1;
-        }
-    }
-
-    fprintf(stderr, "Timeout waiting for v1.x card\n");
-    return SDCARD_FAIL;
-}
-
-int SDFileSystem::initialise_card_v2() {
-    
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        _cmd(55, 0); 
-        if(_cmd(41, 0) == 0) { 
-            _cmd58();
-            return SDCARD_V2;
-        }
-    }
-
-    fprintf(stderr, "Timeout waiting for v2.x card\n");
-    return SDCARD_FAIL;
-}
-
-int SDFileSystem::disk_initialize() {
-
-    int i = initialise_card();
-//    printf("init card = %d\n", i);
-//    printf("OK\n");
-
-    _sectors = _sd_sectors();
-
-    // Set block length to 512 (CMD16)
-    if(_cmd(16, 512) != 0) {
-        fprintf(stderr, "Set 512-byte block timed out\n");
-        return 1;
-    }
-        
-    _spi.frequency(1000000); // Set to 1MHz for data transfer
-    return 0;
-}
-
-int SDFileSystem::disk_write(const char *buffer, int block_number) {
-    // set write address for single block (CMD24)
-    if(_cmd(24, block_number * 512) != 0) {
-        return 1;
-    }
-
-    // send the data block
-    _write(buffer, 512);    
-    return 0;    
-}
-
-int SDFileSystem::disk_read(char *buffer, int block_number) {        
-    // set read address for single block (CMD17)
-    if(_cmd(17, block_number * 512) != 0) {
-        return 1;
-    }
-    
-    // receive the data
-    _read(buffer, 512);
-    return 0;
-}
-
-int SDFileSystem::disk_status() { return 0; }
-int SDFileSystem::disk_sync() { return 0; }
-int SDFileSystem::disk_sectors() { return _sectors; }
-
-// PRIVATE FUNCTIONS
-
-int SDFileSystem::_cmd(int cmd, int arg) {
-    _cs = 0; 
-
-    // send a command
-    _spi.write(0x40 | cmd);
-    _spi.write(arg >> 24);
-    _spi.write(arg >> 16);
-    _spi.write(arg >> 8);
-    _spi.write(arg >> 0);
-    _spi.write(0x95);
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        int response = _spi.write(0xFF);
-        if(!(response & 0x80)) {
-            _cs = 1;
-            _spi.write(0xFF);
-            return response;
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-int SDFileSystem::_cmdx(int cmd, int arg) {
-    _cs = 0; 
-
-    // send a command
-    _spi.write(0x40 | cmd);
-    _spi.write(arg >> 24);
-    _spi.write(arg >> 16);
-    _spi.write(arg >> 8);
-    _spi.write(arg >> 0);
-    _spi.write(0x95);
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        int response = _spi.write(0xFF);
-        if(!(response & 0x80)) {
-            return response;
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-
-
-int SDFileSystem::_cmd58() {
-    _cs = 0; 
-    int arg = 0;
-    
-    // send a command
-    _spi.write(0x40 | 58);
-    _spi.write(arg >> 24);
-    _spi.write(arg >> 16);
-    _spi.write(arg >> 8);
-    _spi.write(arg >> 0);
-    _spi.write(0x95);
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
-        int response = _spi.write(0xFF);
-        if(!(response & 0x80)) {
-            int ocr = _spi.write(0xFF) << 24;
-            ocr |= _spi.write(0xFF) << 16;
-            ocr |= _spi.write(0xFF) << 8;
-            ocr |= _spi.write(0xFF) << 0;
-//            printf("OCR = 0x%08X\n", ocr);
-            _cs = 1;
-            _spi.write(0xFF);
-            return response;
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-
-int SDFileSystem::_cmd8() {
-    _cs = 0; 
-    
-    // send a command
-    _spi.write(0x40 | 8); // CMD8
-    _spi.write(0x00);     // reserved
-    _spi.write(0x00);     // reserved
-    _spi.write(0x01);     // 3.3v
-    _spi.write(0xAA);     // check pattern
-    _spi.write(0x87);     // crc
-
-    // wait for the repsonse (response[7] == 0)
-    for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
-        char response[5];
-        response[0] = _spi.write(0xFF);
-        if(!(response[0] & 0x80)) {
-                for(int j=1; j<5; j++) {
-                    response[i] = _spi.write(0xFF);
-                }
-                _cs = 1;
-                _spi.write(0xFF);
-                return response[0];
-        }
-    }
-    _cs = 1;
-    _spi.write(0xFF);
-    return -1; // timeout
-}
-
-int SDFileSystem::_read(char *buffer, int length) {
-    _cs = 0;
-
-    // read until start byte (0xFF)
-    while(_spi.write(0xFF) != 0xFE);
-
-    // read data
-    for(int i=0; i<length; i++) {
-        buffer[i] = _spi.write(0xFF);
-    }
-    _spi.write(0xFF); // checksum
-    _spi.write(0xFF);
-
-    _cs = 1;    
-    _spi.write(0xFF);
-    return 0;
-}
-
-int SDFileSystem::_write(const char *buffer, int length) {
-    _cs = 0;
-    
-    // indicate start of block
-    _spi.write(0xFE);
-    
-    // write the data
-    for(int i=0; i<length; i++) {
-        _spi.write(buffer[i]);
-    }
-    
-    // write the checksum
-    _spi.write(0xFF); 
-    _spi.write(0xFF);
-
-    // check the repsonse token
-    if((_spi.write(0xFF) & 0x1F) != 0x05) {
-        _cs = 1;
-        _spi.write(0xFF);        
-        return 1;
-    }
-
-    // wait for write to finish
-    while(_spi.write(0xFF) == 0);
-
-    _cs = 1; 
-    _spi.write(0xFF);
-    return 0;
-}
-
-static int ext_bits(char *data, int msb, int lsb) {
-    int bits = 0;
-    int size = 1 + msb - lsb; 
-    for(int i=0; i<size; i++) {
-        int position = lsb + i;
-        int byte = 15 - (position >> 3);
-        int bit = position & 0x7;
-        int value = (data[byte] >> bit) & 1;
-        bits |= value << i;
-    }
-    return bits;
-}
-
-int SDFileSystem::_sd_sectors() {
-
-    // CMD9, Response R2 (R1 byte + 16-byte block read)
-    if(_cmdx(9, 0) != 0) {
-        fprintf(stderr, "Didn't get a response from the disk\n");
-        return 0;
-    }
-    
-    char csd[16];    
-    if(_read(csd, 16) != 0) {
-        fprintf(stderr, "Couldn't read csd response from disk\n");
-        return 0;
-    }
-
-    // csd_structure : csd[127:126]
-    // c_size        : csd[73:62]
-    // c_size_mult   : csd[49:47]
-    // read_bl_len   : csd[83:80] - the *maximum* read block length
-
-    int csd_structure = ext_bits(csd, 127, 126);
-    int c_size = ext_bits(csd, 73, 62);
-    int c_size_mult = ext_bits(csd, 49, 47);
-    int read_bl_len = ext_bits(csd, 83, 80);
-
-//    printf("CSD_STRUCT = %d\n", csd_structure);
-    
-    if(csd_structure != 0) {
-        fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
-        return 0;
-    }
-             
-    // memory capacity = BLOCKNR * BLOCK_LEN
-    // where
-    //  BLOCKNR = (C_SIZE+1) * MULT
-    //  MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
-    //  BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)         
-                            
-    int block_len = 1 << read_bl_len;
-    int mult = 1 << (c_size_mult + 2);
-    int blocknr = (c_size + 1) * mult;
-    int capacity = blocknr * block_len;
-        
-    int blocks = capacity / 512;
-        
-    return blocks;
-}