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/* mbed Microcontroller Library - SDFileSystem
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* Copyright (c) 2008-2009, sford
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*/
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// VERY DRAFT CODE! Needs serious rework/refactoring
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/* Introduction
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* ------------
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* SD and MMC cards support a number of interfaces, but common to them all
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* is one based on SPI. This is the one I'm implmenting because it means
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* it is much more portable even though not so performant, and we already
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* have the mbed SPI Interface!
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*
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* The main reference I'm using is Chapter 7, "SPI Mode" of:
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* http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
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*
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* SPI Startup
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* -----------
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* The SD card powers up in SD mode. The SPI interface mode is selected by
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* asserting CS low and sending the reset command (CMD0). The card will
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* respond with a (R1) response.
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*
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* CMD8 is optionally sent to determine the voltage range supported, and
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* indirectly determine whether it is a version 1.x SD/non-SD card or
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* version 2.x. I'll just ignore this for now.
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*
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* ACMD41 is repeatedly issued to initialise the card, until "in idle"
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* (bit 0) of the R1 response goes to '0', indicating it is initialised.
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*
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* You should also indicate whether the host supports High Capicity cards,
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* and check whether the card is high capacity - i'll also ignore this
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*
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* SPI Protocol
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* ------------
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* The SD SPI protocol is based on transactions made up of 8-bit words, with
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* the host starting every bus transaction by asserting the CS signal low. The
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* card always responds to commands, data blocks and errors.
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*
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* The protocol supports a CRC, but by default it is off (except for the
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* first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
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* I'll leave the CRC off I think!
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*
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* Standard capacity cards have variable data block sizes, whereas High
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* Capacity cards fix the size of data block to 512 bytes. I'll therefore
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* just always use the Standard Capacity cards with a block size of 512 bytes.
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* This is set with CMD16.
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*
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* You can read and write single blocks (CMD17, CMD25) or multiple blocks
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* (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
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* the card gets a read command, it responds with a response token, and then
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* a data token or an error.
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*
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* SPI Command Format
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* ------------------
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* Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
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*
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* +---------------+------------+------------+-----------+----------+--------------+
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* | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
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* +---------------+------------+------------+-----------+----------+--------------+
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*
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* As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
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*
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* All Application Specific commands shall be preceded with APP_CMD (CMD55).
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*
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* SPI Response Format
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* -------------------
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* The main response format (R1) is a status byte (normally zero). Key flags:
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* idle - 1 if the card is in an idle state/initialising
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* cmd - 1 if an illegal command code was detected
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*
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* +-------------------------------------------------+
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* R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
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* +-------------------------------------------------+
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*
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* R1b is the same, except it is followed by a busy signal (zeros) until
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* the first non-zero byte when it is ready again.
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*
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* Data Response Token
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* -------------------
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* Every data block written to the card is acknowledged by a byte
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* response token
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*
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* +----------------------+
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* | xxx | 0 | status | 1 |
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* +----------------------+
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* 010 - OK!
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* 101 - CRC Error
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* 110 - Write Error
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*
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* Single Block Read and Write
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* ---------------------------
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*
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* Block transfers have a byte header, followed by the data, followed
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* by a 16-bit CRC. In our case, the data will always be 512 bytes.
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*
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* +------+---------+---------+- - - -+---------+-----------+----------+
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* | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
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* +------+---------+---------+- - - -+---------+-----------+----------+
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*/
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#include "SDFileSystem.h"
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#define SD_COMMAND_TIMEOUT 5000
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SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
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FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
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_cs = 1;
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}
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#define R1_IDLE_STATE (1 << 0)
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#define R1_ERASE_RESET (1 << 1)
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#define R1_ILLEGAL_COMMAND (1 << 2)
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#define R1_COM_CRC_ERROR (1 << 3)
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#define R1_ERASE_SEQUENCE_ERROR (1 << 4)
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#define R1_ADDRESS_ERROR (1 << 5)
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#define R1_PARAMETER_ERROR (1 << 6)
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// Types
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// - v1.x Standard Capacity
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// - v2.x Standard Capacity
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// - v2.x High Capacity
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// - Not recognised as an SD Card
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#define SDCARD_FAIL 0
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#define SDCARD_V1 1
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#define SDCARD_V2 2
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#define SDCARD_V2HC 3
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int SDFileSystem::initialise_card() {
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// Set to 100kHz for initialisation, and clock card with cs = 1
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_spi.frequency(100000);
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_cs = 1;
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for(int i=0; i<16; i++) {
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_spi.write(0xFF);
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}
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// send CMD0, should return with all zeros except IDLE STATE set (bit 0)
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if(_cmd(0, 0) != R1_IDLE_STATE) {
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fprintf(stderr, "No disk, or could not put SD card in to SPI idle state\n");
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return SDCARD_FAIL;
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}
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// send CMD8 to determine whther it is ver 2.x
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int r = _cmd8();
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if(r == R1_IDLE_STATE) {
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return initialise_card_v2();
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} else if(r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
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return initialise_card_v1();
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} else {
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fprintf(stderr, "Not in idle state after sending CMD8 (not an SD card?)\n");
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return SDCARD_FAIL;
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}
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}
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int SDFileSystem::initialise_card_v1() {
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for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
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_cmd(55, 0);
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158
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if(_cmd(41, 0) == 0) {
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return SDCARD_V1;
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160
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}
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}
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162
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fprintf(stderr, "Timeout waiting for v1.x card\n");
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return SDCARD_FAIL;
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165
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}
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166
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int SDFileSystem::initialise_card_v2() {
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168
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169
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for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
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_cmd(55, 0);
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171
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if(_cmd(41, 0) == 0) {
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_cmd58();
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return SDCARD_V2;
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174
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}
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}
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176
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3:68ef62208d4d
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fprintf(stderr, "Timeout waiting for v2.x card\n");
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return SDCARD_FAIL;
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179
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}
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180
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181
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int SDFileSystem::disk_initialize() {
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int i = initialise_card();
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// printf("init card = %d\n", i);
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// printf("OK\n");
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186
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187
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_sectors = _sd_sectors();
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188
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1:2dec995d53f8
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// Set block length to 512 (CMD16)
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if(_cmd(16, 512) != 0) {
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fprintf(stderr, "Set 512-byte block timed out\n");
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return 1;
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}
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194
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_spi.frequency(1000000); // Set to 1MHz for data transfer
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return 0;
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197
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}
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198
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int SDFileSystem::disk_write(const char *buffer, int block_number) {
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1:2dec995d53f8
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200
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// set write address for single block (CMD24)
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1:2dec995d53f8
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201
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if(_cmd(24, block_number * 512) != 0) {
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1:2dec995d53f8
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202
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return 1;
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1:2dec995d53f8
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203
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}
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1:2dec995d53f8
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204
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1:2dec995d53f8
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205
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// send the data block
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1:2dec995d53f8
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206
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_write(buffer, 512);
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207
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return 0;
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1:2dec995d53f8
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208
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}
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209
|
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210
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int SDFileSystem::disk_read(char *buffer, int block_number) {
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simon |
1:2dec995d53f8
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211
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// set read address for single block (CMD17)
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simon |
1:2dec995d53f8
|
212
|
if(_cmd(17, block_number * 512) != 0) {
|
simon |
1:2dec995d53f8
|
213
|
return 1;
|
simon |
1:2dec995d53f8
|
214
|
}
|
simon |
1:2dec995d53f8
|
215
|
|
simon |
1:2dec995d53f8
|
216
|
// receive the data
|
simon |
1:2dec995d53f8
|
217
|
_read(buffer, 512);
|
simon |
1:2dec995d53f8
|
218
|
return 0;
|
simon |
1:2dec995d53f8
|
219
|
}
|
simon |
1:2dec995d53f8
|
220
|
|
simon |
1:2dec995d53f8
|
221
|
int SDFileSystem::disk_status() { return 0; }
|
simon |
1:2dec995d53f8
|
222
|
int SDFileSystem::disk_sync() { return 0; }
|
simon |
1:2dec995d53f8
|
223
|
int SDFileSystem::disk_sectors() { return _sectors; }
|
simon |
1:2dec995d53f8
|
224
|
|
simon |
1:2dec995d53f8
|
225
|
// PRIVATE FUNCTIONS
|
simon |
1:2dec995d53f8
|
226
|
|
simon |
1:2dec995d53f8
|
227
|
int SDFileSystem::_cmd(int cmd, int arg) {
|
simon |
1:2dec995d53f8
|
228
|
_cs = 0;
|
simon |
1:2dec995d53f8
|
229
|
|
simon |
1:2dec995d53f8
|
230
|
// send a command
|
simon |
1:2dec995d53f8
|
231
|
_spi.write(0x40 | cmd);
|
simon |
1:2dec995d53f8
|
232
|
_spi.write(arg >> 24);
|
simon |
1:2dec995d53f8
|
233
|
_spi.write(arg >> 16);
|
simon |
1:2dec995d53f8
|
234
|
_spi.write(arg >> 8);
|
simon |
1:2dec995d53f8
|
235
|
_spi.write(arg >> 0);
|
simon |
1:2dec995d53f8
|
236
|
_spi.write(0x95);
|
simon |
1:2dec995d53f8
|
237
|
|
simon |
1:2dec995d53f8
|
238
|
// wait for the repsonse (response[7] == 0)
|
simon |
1:2dec995d53f8
|
239
|
for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
|
simon |
1:2dec995d53f8
|
240
|
int response = _spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
241
|
if(!(response & 0x80)) {
|
simon |
1:2dec995d53f8
|
242
|
_cs = 1;
|
simon |
1:2dec995d53f8
|
243
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
244
|
return response;
|
simon |
1:2dec995d53f8
|
245
|
}
|
simon |
1:2dec995d53f8
|
246
|
}
|
simon |
1:2dec995d53f8
|
247
|
_cs = 1;
|
simon |
1:2dec995d53f8
|
248
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
249
|
return -1; // timeout
|
simon |
1:2dec995d53f8
|
250
|
}
|
simon |
3:68ef62208d4d
|
251
|
int SDFileSystem::_cmdx(int cmd, int arg) {
|
simon |
3:68ef62208d4d
|
252
|
_cs = 0;
|
simon |
3:68ef62208d4d
|
253
|
|
simon |
3:68ef62208d4d
|
254
|
// send a command
|
simon |
3:68ef62208d4d
|
255
|
_spi.write(0x40 | cmd);
|
simon |
3:68ef62208d4d
|
256
|
_spi.write(arg >> 24);
|
simon |
3:68ef62208d4d
|
257
|
_spi.write(arg >> 16);
|
simon |
3:68ef62208d4d
|
258
|
_spi.write(arg >> 8);
|
simon |
3:68ef62208d4d
|
259
|
_spi.write(arg >> 0);
|
simon |
3:68ef62208d4d
|
260
|
_spi.write(0x95);
|
simon |
3:68ef62208d4d
|
261
|
|
simon |
3:68ef62208d4d
|
262
|
// wait for the repsonse (response[7] == 0)
|
simon |
3:68ef62208d4d
|
263
|
for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
|
simon |
3:68ef62208d4d
|
264
|
int response = _spi.write(0xFF);
|
simon |
3:68ef62208d4d
|
265
|
if(!(response & 0x80)) {
|
simon |
3:68ef62208d4d
|
266
|
return response;
|
simon |
3:68ef62208d4d
|
267
|
}
|
simon |
3:68ef62208d4d
|
268
|
}
|
simon |
3:68ef62208d4d
|
269
|
_cs = 1;
|
simon |
3:68ef62208d4d
|
270
|
_spi.write(0xFF);
|
simon |
3:68ef62208d4d
|
271
|
return -1; // timeout
|
simon |
3:68ef62208d4d
|
272
|
}
|
simon |
3:68ef62208d4d
|
273
|
|
simon |
3:68ef62208d4d
|
274
|
|
simon |
3:68ef62208d4d
|
275
|
int SDFileSystem::_cmd58() {
|
simon |
3:68ef62208d4d
|
276
|
_cs = 0;
|
simon |
3:68ef62208d4d
|
277
|
int arg = 0;
|
simon |
3:68ef62208d4d
|
278
|
|
simon |
3:68ef62208d4d
|
279
|
// send a command
|
simon |
3:68ef62208d4d
|
280
|
_spi.write(0x40 | 58);
|
simon |
3:68ef62208d4d
|
281
|
_spi.write(arg >> 24);
|
simon |
3:68ef62208d4d
|
282
|
_spi.write(arg >> 16);
|
simon |
3:68ef62208d4d
|
283
|
_spi.write(arg >> 8);
|
simon |
3:68ef62208d4d
|
284
|
_spi.write(arg >> 0);
|
simon |
3:68ef62208d4d
|
285
|
_spi.write(0x95);
|
simon |
3:68ef62208d4d
|
286
|
|
simon |
3:68ef62208d4d
|
287
|
// wait for the repsonse (response[7] == 0)
|
simon |
3:68ef62208d4d
|
288
|
for(int i=0; i<SD_COMMAND_TIMEOUT; i++) {
|
simon |
3:68ef62208d4d
|
289
|
int response = _spi.write(0xFF);
|
simon |
3:68ef62208d4d
|
290
|
if(!(response & 0x80)) {
|
simon |
3:68ef62208d4d
|
291
|
int ocr = _spi.write(0xFF) << 24;
|
simon |
3:68ef62208d4d
|
292
|
ocr |= _spi.write(0xFF) << 16;
|
simon |
3:68ef62208d4d
|
293
|
ocr |= _spi.write(0xFF) << 8;
|
simon |
3:68ef62208d4d
|
294
|
ocr |= _spi.write(0xFF) << 0;
|
simon |
3:68ef62208d4d
|
295
|
// printf("OCR = 0x%08X\n", ocr);
|
simon |
3:68ef62208d4d
|
296
|
_cs = 1;
|
simon |
3:68ef62208d4d
|
297
|
_spi.write(0xFF);
|
simon |
3:68ef62208d4d
|
298
|
return response;
|
simon |
3:68ef62208d4d
|
299
|
}
|
simon |
3:68ef62208d4d
|
300
|
}
|
simon |
3:68ef62208d4d
|
301
|
_cs = 1;
|
simon |
3:68ef62208d4d
|
302
|
_spi.write(0xFF);
|
simon |
3:68ef62208d4d
|
303
|
return -1; // timeout
|
simon |
3:68ef62208d4d
|
304
|
}
|
simon |
1:2dec995d53f8
|
305
|
|
simon |
2:849162a1207f
|
306
|
int SDFileSystem::_cmd8() {
|
simon |
2:849162a1207f
|
307
|
_cs = 0;
|
simon |
2:849162a1207f
|
308
|
|
simon |
2:849162a1207f
|
309
|
// send a command
|
simon |
2:849162a1207f
|
310
|
_spi.write(0x40 | 8); // CMD8
|
simon |
2:849162a1207f
|
311
|
_spi.write(0x00); // reserved
|
simon |
2:849162a1207f
|
312
|
_spi.write(0x00); // reserved
|
simon |
2:849162a1207f
|
313
|
_spi.write(0x01); // 3.3v
|
simon |
2:849162a1207f
|
314
|
_spi.write(0xAA); // check pattern
|
simon |
2:849162a1207f
|
315
|
_spi.write(0x87); // crc
|
simon |
2:849162a1207f
|
316
|
|
simon |
2:849162a1207f
|
317
|
// wait for the repsonse (response[7] == 0)
|
simon |
2:849162a1207f
|
318
|
for(int i=0; i<SD_COMMAND_TIMEOUT * 1000; i++) {
|
simon |
2:849162a1207f
|
319
|
char response[5];
|
simon |
2:849162a1207f
|
320
|
response[0] = _spi.write(0xFF);
|
simon |
2:849162a1207f
|
321
|
if(!(response[0] & 0x80)) {
|
simon |
2:849162a1207f
|
322
|
for(int j=1; j<5; j++) {
|
simon |
2:849162a1207f
|
323
|
response[i] = _spi.write(0xFF);
|
simon |
2:849162a1207f
|
324
|
}
|
simon |
2:849162a1207f
|
325
|
_cs = 1;
|
simon |
2:849162a1207f
|
326
|
_spi.write(0xFF);
|
simon |
2:849162a1207f
|
327
|
return response[0];
|
simon |
2:849162a1207f
|
328
|
}
|
simon |
2:849162a1207f
|
329
|
}
|
simon |
2:849162a1207f
|
330
|
_cs = 1;
|
simon |
2:849162a1207f
|
331
|
_spi.write(0xFF);
|
simon |
2:849162a1207f
|
332
|
return -1; // timeout
|
simon |
2:849162a1207f
|
333
|
}
|
simon |
2:849162a1207f
|
334
|
|
simon |
1:2dec995d53f8
|
335
|
int SDFileSystem::_read(char *buffer, int length) {
|
simon |
1:2dec995d53f8
|
336
|
_cs = 0;
|
simon |
1:2dec995d53f8
|
337
|
|
simon |
1:2dec995d53f8
|
338
|
// read until start byte (0xFF)
|
simon |
1:2dec995d53f8
|
339
|
while(_spi.write(0xFF) != 0xFE);
|
simon |
1:2dec995d53f8
|
340
|
|
simon |
1:2dec995d53f8
|
341
|
// read data
|
simon |
1:2dec995d53f8
|
342
|
for(int i=0; i<length; i++) {
|
simon |
1:2dec995d53f8
|
343
|
buffer[i] = _spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
344
|
}
|
simon |
1:2dec995d53f8
|
345
|
_spi.write(0xFF); // checksum
|
simon |
1:2dec995d53f8
|
346
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
347
|
|
simon |
1:2dec995d53f8
|
348
|
_cs = 1;
|
simon |
1:2dec995d53f8
|
349
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
350
|
return 0;
|
simon |
1:2dec995d53f8
|
351
|
}
|
simon |
1:2dec995d53f8
|
352
|
|
simon |
1:2dec995d53f8
|
353
|
int SDFileSystem::_write(const char *buffer, int length) {
|
simon |
1:2dec995d53f8
|
354
|
_cs = 0;
|
simon |
1:2dec995d53f8
|
355
|
|
simon |
1:2dec995d53f8
|
356
|
// indicate start of block
|
simon |
1:2dec995d53f8
|
357
|
_spi.write(0xFE);
|
simon |
1:2dec995d53f8
|
358
|
|
simon |
1:2dec995d53f8
|
359
|
// write the data
|
simon |
1:2dec995d53f8
|
360
|
for(int i=0; i<length; i++) {
|
simon |
1:2dec995d53f8
|
361
|
_spi.write(buffer[i]);
|
simon |
1:2dec995d53f8
|
362
|
}
|
simon |
1:2dec995d53f8
|
363
|
|
simon |
1:2dec995d53f8
|
364
|
// write the checksum
|
simon |
1:2dec995d53f8
|
365
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
366
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
367
|
|
simon |
1:2dec995d53f8
|
368
|
// check the repsonse token
|
simon |
1:2dec995d53f8
|
369
|
if((_spi.write(0xFF) & 0x1F) != 0x05) {
|
simon |
1:2dec995d53f8
|
370
|
_cs = 1;
|
simon |
1:2dec995d53f8
|
371
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
372
|
return 1;
|
simon |
1:2dec995d53f8
|
373
|
}
|
simon |
1:2dec995d53f8
|
374
|
|
simon |
1:2dec995d53f8
|
375
|
// wait for write to finish
|
simon |
1:2dec995d53f8
|
376
|
while(_spi.write(0xFF) == 0);
|
simon |
1:2dec995d53f8
|
377
|
|
simon |
1:2dec995d53f8
|
378
|
_cs = 1;
|
simon |
1:2dec995d53f8
|
379
|
_spi.write(0xFF);
|
simon |
1:2dec995d53f8
|
380
|
return 0;
|
simon |
1:2dec995d53f8
|
381
|
}
|
simon |
1:2dec995d53f8
|
382
|
|
simon |
1:2dec995d53f8
|
383
|
static int ext_bits(char *data, int msb, int lsb) {
|
simon |
1:2dec995d53f8
|
384
|
int bits = 0;
|
simon |
1:2dec995d53f8
|
385
|
int size = 1 + msb - lsb;
|
simon |
1:2dec995d53f8
|
386
|
for(int i=0; i<size; i++) {
|
simon |
1:2dec995d53f8
|
387
|
int position = lsb + i;
|
simon |
1:2dec995d53f8
|
388
|
int byte = 15 - (position >> 3);
|
simon |
1:2dec995d53f8
|
389
|
int bit = position & 0x7;
|
simon |
1:2dec995d53f8
|
390
|
int value = (data[byte] >> bit) & 1;
|
simon |
1:2dec995d53f8
|
391
|
bits |= value << i;
|
simon |
1:2dec995d53f8
|
392
|
}
|
simon |
1:2dec995d53f8
|
393
|
return bits;
|
simon |
1:2dec995d53f8
|
394
|
}
|
simon |
1:2dec995d53f8
|
395
|
|
simon |
1:2dec995d53f8
|
396
|
int SDFileSystem::_sd_sectors() {
|
simon |
1:2dec995d53f8
|
397
|
|
simon |
1:2dec995d53f8
|
398
|
// CMD9, Response R2 (R1 byte + 16-byte block read)
|
simon |
3:68ef62208d4d
|
399
|
if(_cmdx(9, 0) != 0) {
|
simon |
1:2dec995d53f8
|
400
|
fprintf(stderr, "Didn't get a response from the disk\n");
|
simon |
1:2dec995d53f8
|
401
|
return 0;
|
simon |
1:2dec995d53f8
|
402
|
}
|
simon |
1:2dec995d53f8
|
403
|
|
simon |
1:2dec995d53f8
|
404
|
char csd[16];
|
simon |
1:2dec995d53f8
|
405
|
if(_read(csd, 16) != 0) {
|
simon |
1:2dec995d53f8
|
406
|
fprintf(stderr, "Couldn't read csd response from disk\n");
|
simon |
1:2dec995d53f8
|
407
|
return 0;
|
simon |
1:2dec995d53f8
|
408
|
}
|
simon |
1:2dec995d53f8
|
409
|
|
simon |
1:2dec995d53f8
|
410
|
// csd_structure : csd[127:126]
|
simon |
1:2dec995d53f8
|
411
|
// c_size : csd[73:62]
|
simon |
1:2dec995d53f8
|
412
|
// c_size_mult : csd[49:47]
|
simon |
3:68ef62208d4d
|
413
|
// read_bl_len : csd[83:80] - the *maximum* read block length
|
simon |
1:2dec995d53f8
|
414
|
|
simon |
1:2dec995d53f8
|
415
|
int csd_structure = ext_bits(csd, 127, 126);
|
simon |
1:2dec995d53f8
|
416
|
int c_size = ext_bits(csd, 73, 62);
|
simon |
1:2dec995d53f8
|
417
|
int c_size_mult = ext_bits(csd, 49, 47);
|
simon |
1:2dec995d53f8
|
418
|
int read_bl_len = ext_bits(csd, 83, 80);
|
simon |
3:68ef62208d4d
|
419
|
|
simon |
3:68ef62208d4d
|
420
|
// printf("CSD_STRUCT = %d\n", csd_structure);
|
simon |
1:2dec995d53f8
|
421
|
|
simon |
1:2dec995d53f8
|
422
|
if(csd_structure != 0) {
|
simon |
3:68ef62208d4d
|
423
|
fprintf(stderr, "This disk tastes funny! I only know about type 0 CSD structures\n");
|
simon |
1:2dec995d53f8
|
424
|
return 0;
|
simon |
1:2dec995d53f8
|
425
|
}
|
simon |
3:68ef62208d4d
|
426
|
|
simon |
3:68ef62208d4d
|
427
|
// memory capacity = BLOCKNR * BLOCK_LEN
|
simon |
3:68ef62208d4d
|
428
|
// where
|
simon |
3:68ef62208d4d
|
429
|
// BLOCKNR = (C_SIZE+1) * MULT
|
simon |
3:68ef62208d4d
|
430
|
// MULT = 2^(C_SIZE_MULT+2) (C_SIZE_MULT < 8)
|
simon |
3:68ef62208d4d
|
431
|
// BLOCK_LEN = 2^READ_BL_LEN, (READ_BL_LEN < 12)
|
simon |
1:2dec995d53f8
|
432
|
|
simon |
3:68ef62208d4d
|
433
|
int block_len = 1 << read_bl_len;
|
simon |
3:68ef62208d4d
|
434
|
int mult = 1 << (c_size_mult + 2);
|
simon |
3:68ef62208d4d
|
435
|
int blocknr = (c_size + 1) * mult;
|
simon |
3:68ef62208d4d
|
436
|
int capacity = blocknr * block_len;
|
simon |
3:68ef62208d4d
|
437
|
|
simon |
3:68ef62208d4d
|
438
|
int blocks = capacity / 512;
|
simon |
3:68ef62208d4d
|
439
|
|
simon |
1:2dec995d53f8
|
440
|
return blocks;
|
simon |
1:2dec995d53f8
|
441
|
}
|