Sergeh Vartanian
Final Report
Fork of
ecu_reader
by 
Sukkin Pang
Diff: SDFileSystem.cpp
- Revision:
- 6:dae9630af6e3
- Parent:
- 5:46a6a3e36e05
--- a/SDFileSystem.cpp Tue Aug 28 13:16:46 2012 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,457 +0,0 @@
-/* mbed SDFileSystem Library, for providing file access to SD cards
- * Copyright (c) 2008-2010, sford
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-/* 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;
-}