1 | /* mbed Microcontroller Library
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2 | * Copyright (c) 2006-2012 ARM Limited
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3 | *
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4 | * Permission is hereby granted, free of charge, to any person obtaining a copy
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5 | * of this software and associated documentation files (the "Software"), to deal
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6 | * in the Software without restriction, including without limitation the rights
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7 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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8 | * copies of the Software, and to permit persons to whom the Software is
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9 | * furnished to do so, subject to the following conditions:
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10 | *
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11 | * The above copyright notice and this permission notice shall be included in
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12 | * all copies or substantial portions of the Software.
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13 | *
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14 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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15 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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16 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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17 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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18 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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19 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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20 | * SOFTWARE.
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21 | */
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22 |
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23 | /* Introduction
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24 | * ------------
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25 | * SD and MMC cards support a number of interfaces, but common to them all
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26 | * is one based on SPI. This is the one I'm implmenting because it means
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27 | * it is much more portable even though not so performant, and we already
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28 | * have the mbed SPI Interface!
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29 | *
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30 | * The main reference I'm using is Chapter 7, "SPI Mode" of:
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31 | * http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf
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32 | *
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33 | * SPI Startup
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34 | * -----------
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35 | * The SD card powers up in SD mode. The SPI interface mode is selected by
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36 | * asserting CS low and sending the reset command (CMD0). The card will
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37 | * respond with a (R1) response.
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38 | *
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39 | * CMD8 is optionally sent to determine the voltage range supported, and
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40 | * indirectly determine whether it is a version 1.x SD/non-SD card or
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41 | * version 2.x. I'll just ignore this for now.
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42 | *
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43 | * ACMD41 is repeatedly issued to initialise the card, until "in idle"
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44 | * (bit 0) of the R1 response goes to '0', indicating it is initialised.
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45 | *
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46 | * You should also indicate whether the host supports High Capicity cards,
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47 | * and check whether the card is high capacity - i'll also ignore this
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48 | *
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49 | * SPI Protocol
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50 | * ------------
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51 | * The SD SPI protocol is based on transactions made up of 8-bit words, with
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52 | * the host starting every bus transaction by asserting the CS signal low. The
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53 | * card always responds to commands, data blocks and errors.
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54 | *
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55 | * The protocol supports a CRC, but by default it is off (except for the
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56 | * first reset CMD0, where the CRC can just be pre-calculated, and CMD8)
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57 | * I'll leave the CRC off I think!
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58 | *
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59 | * Standard capacity cards have variable data block sizes, whereas High
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60 | * Capacity cards fix the size of data block to 512 bytes. I'll therefore
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61 | * just always use the Standard Capacity cards with a block size of 512 bytes.
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62 | * This is set with CMD16.
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63 | *
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64 | * You can read and write single blocks (CMD17, CMD25) or multiple blocks
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65 | * (CMD18, CMD25). For simplicity, I'll just use single block accesses. When
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66 | * the card gets a read command, it responds with a response token, and then
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67 | * a data token or an error.
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68 | *
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69 | * SPI Command Format
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70 | * ------------------
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71 | * Commands are 6-bytes long, containing the command, 32-bit argument, and CRC.
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72 | *
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73 | * +---------------+------------+------------+-----------+----------+--------------+
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74 | * | 01 | cmd[5:0] | arg[31:24] | arg[23:16] | arg[15:8] | arg[7:0] | crc[6:0] | 1 |
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75 | * +---------------+------------+------------+-----------+----------+--------------+
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76 | *
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77 | * As I'm not using CRC, I can fix that byte to what is needed for CMD0 (0x95)
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78 | *
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79 | * All Application Specific commands shall be preceded with APP_CMD (CMD55).
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80 | *
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81 | * SPI Response Format
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82 | * -------------------
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83 | * The main response format (R1) is a status byte (normally zero). Key flags:
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84 | * idle - 1 if the card is in an idle state/initialising
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85 | * cmd - 1 if an illegal command code was detected
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86 | *
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87 | * +-------------------------------------------------+
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88 | * R1 | 0 | arg | addr | seq | crc | cmd | erase | idle |
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89 | * +-------------------------------------------------+
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90 | *
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91 | * R1b is the same, except it is followed by a busy signal (zeros) until
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92 | * the first non-zero byte when it is ready again.
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93 | *
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94 | * Data Response Token
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95 | * -------------------
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96 | * Every data block written to the card is acknowledged by a byte
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97 | * response token
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98 | *
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99 | * +----------------------+
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100 | * | xxx | 0 | status | 1 |
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101 | * +----------------------+
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102 | * 010 - OK!
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103 | * 101 - CRC Error
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104 | * 110 - Write Error
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105 | *
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106 | * Single Block Read and Write
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107 | * ---------------------------
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108 | *
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109 | * Block transfers have a byte header, followed by the data, followed
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110 | * by a 16-bit CRC. In our case, the data will always be 512 bytes.
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111 | *
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112 | * +------+---------+---------+- - - -+---------+-----------+----------+
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113 | * | 0xFE | data[0] | data[1] | | data[n] | crc[15:8] | crc[7:0] |
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114 | * +------+---------+---------+- - - -+---------+-----------+----------+
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115 | */
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116 | #include "sdfs.h"
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117 | //#include "mbed_debug.h"
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118 | #include "wait_api.h"
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119 |
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120 | #define debug(str, ...)
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121 | #define debug_if(cond, strt, ...) if(cond){ debug(str, __ARGS__); }
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122 |
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123 | static int sdfs_initialise_card_v1(sdfs_t *obj);
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124 | static int sdfs_initialise_card_v2(sdfs_t *obj);
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125 | static int sdfs__cmd(sdfs_t *obj, int cmd, int arg);
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126 | static int sdfs__cmd8(sdfs_t *obj);
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127 | static int sdfs__cmd58(sdfs_t *obj);
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128 | static uint64_t sdfs__sd_sectors(sdfs_t *obj);
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129 | static int sdfs__write(sdfs_t *obj, const uint8_t*buffer, uint32_t length);
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130 | static int sdfs__read(sdfs_t *obj, uint8_t *buffer, uint32_t length);
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131 |
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132 | #define SD_COMMAND_TIMEOUT 5000
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133 |
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134 | #define SD_DBG 0
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135 |
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136 | sdfs_init(sdfs_t *obj, PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name)
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137 | {
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138 | obj->name = name;
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139 | spi_init(&obj->_spi, mosi, miso, sclk, NC);
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140 | gpio_init_out(&obj->_cs, cs);
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141 | gpio_write(&obj->_cs, 1);
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142 |
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143 | // Set default to 100kHz for initialisation and 1MHz for data transfer
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144 | obj->_init_sck = 100000;
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145 | obj->_transfer_sck = 1000000;
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146 | }
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147 |
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148 | #define R1_IDLE_STATE (1 << 0)
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149 | #define R1_ERASE_RESET (1 << 1)
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150 | #define R1_ILLEGAL_COMMAND (1 << 2)
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151 | #define R1_COM_CRC_ERROR (1 << 3)
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152 | #define R1_ERASE_SEQUENCE_ERROR (1 << 4)
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153 | #define R1_ADDRESS_ERROR (1 << 5)
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154 | #define R1_PARAMETER_ERROR (1 << 6)
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155 |
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156 | // Types
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157 | #define SDCARD_FAIL 0 //!< v1.x Standard Capacity
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158 | #define SDCARD_V1 1 //!< v2.x Standard Capacity
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159 | #define SDCARD_V2 2 //!< v2.x High Capacity
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160 | #define SDCARD_V2HC 3 //!< Not recognised as an SD Card
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161 |
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162 | int sdfs_initialise_card(sdfs_t *obj)
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163 | {
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164 | spi_format(&obj->_spi, 8, 0, 0);
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165 | // Set to 100kHz for initialisation, and clock card with cs = 1
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166 | spi_frequency(&obj->_spi, obj->_init_sck);
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167 | gpio_write(&obj->_cs, 1);
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168 | for (int i = 0; i < 16; i++) {
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169 | spi_master_write(&obj->_spi, 0xFF);
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170 | }
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171 |
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172 | // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
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173 | if (sdfs__cmd(obj, 0, 0) != R1_IDLE_STATE) {
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174 | debug("No disk, or could not put SD card in to SPI idle state\n");
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175 | return SDCARD_FAIL;
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176 | }
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177 |
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178 | // send CMD8 to determine whther it is ver 2.x
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179 | int r = sdfs__cmd8(obj);
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180 | if (r == R1_IDLE_STATE) {
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181 | return sdfs_initialise_card_v2(obj);
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182 | }
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183 | else if (r == (R1_IDLE_STATE | R1_ILLEGAL_COMMAND)) {
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184 | return sdfs_initialise_card_v1(obj);
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185 | }
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186 | else {
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187 | debug("Not in idle state after sending CMD8 (not an SD card?)\n");
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188 | return SDCARD_FAIL;
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189 | }
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190 | }
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191 |
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192 | static int sdfs_initialise_card_v1(sdfs_t *obj)
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193 | {
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194 | for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
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195 | sdfs__cmd(obj, 55, 0);
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196 | if (sdfs__cmd(obj, 41, 0) == 0) {
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197 | obj->cdv = 512;
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198 | debug_if(SD_DBG, "\n\rInit: SEDCARD_V1\n\r");
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199 | return SDCARD_V1;
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200 | }
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201 | }
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202 |
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203 | debug("Timeout waiting for v1.x card\n");
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204 | return SDCARD_FAIL;
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205 | }
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206 |
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207 | static int sdfs_initialise_card_v2(sdfs_t *obj)
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208 | {
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209 | for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
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210 | wait_ms(50);
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211 | sdfs__cmd58(obj);
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212 | sdfs__cmd(obj, 55, 0);
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213 | if (sdfs__cmd(obj, 41, 0x40000000) == 0) {
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214 | sdfs__cmd58(obj);
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215 | debug_if(SD_DBG, "\n\rInit: SDCARD_V2\n\r");
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216 | obj->cdv = 1;
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217 | return SDCARD_V2;
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218 | }
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219 | }
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220 |
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221 | debug("Timeout waiting for v2.x card\n");
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222 | return SDCARD_FAIL;
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223 | }
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224 |
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225 | int sdfs_initialize(sdfs_t *obj)
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226 | {
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227 | obj->_is_initialized = sdfs_initialise_card(obj);
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228 | if (obj->_is_initialized == 0) {
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229 | debug("Fail to initialize card\n");
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230 | return 1;
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231 | }
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232 | debug_if(SD_DBG, "init card = %d\n", obj->_is_initialized);
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233 | obj->_sectors = sdfs__sd_sectors(obj);
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234 |
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235 | // Set block length to 512 (CMD16)
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236 | if (sdfs__cmd(obj, 16, 512) != 0) {
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237 | debug("Set 512-byte block timed out\n");
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238 | return 1;
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239 | }
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240 |
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241 | // Set SCK for data transfer
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242 | spi_frequency(&obj->_spi, obj->_transfer_sck);
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243 | return 0;
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244 | }
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245 |
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246 | int sdfs_write(sdfs_t *obj, const uint8_t *buffer, uint32_t block_number, uint32_t count)
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247 | {
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248 | if (!obj->_is_initialized) {
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249 | return -1;
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250 | }
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251 |
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252 | for (uint32_t b = block_number; b < block_number + count; b++) {
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253 | // set write address for single block (CMD24)
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254 | if (sdfs__cmd(obj, 24, b * obj->cdv) != 0) {
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255 | return 1;
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256 | }
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257 |
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258 | // send the data block
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259 | sdfs__write(obj, buffer, 512);
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260 | buffer += 512;
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261 | }
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262 |
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263 | return 0;
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264 | }
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265 |
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266 | int sdfs_read(sdfs_t *obj, uint8_t *buffer, uint32_t block_number, uint32_t count)
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267 | {
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268 | if (!obj->_is_initialized) {
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269 | return -1;
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270 | }
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271 |
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272 | for (uint32_t b = block_number; b < block_number + count; b++) {
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273 | // set read address for single block (CMD17)
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274 | if (sdfs__cmd(obj, 17, b * obj->cdv) != 0) {
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275 | return 1;
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276 | }
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277 |
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278 | // receive the data
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279 | sdfs__read(obj, buffer, 512);
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280 | buffer += 512;
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281 | }
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282 |
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283 | return 0;
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284 | }
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285 |
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286 | int sdfs_status(sdfs_t *obj)
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287 | {
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288 | // FATFileSystem::disk_status() returns 0 when initialized
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289 | if (obj->_is_initialized) {
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290 | return 0;
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291 | }
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292 | else {
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293 | return 1;
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294 | }
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295 | }
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296 | int sdfs_sync(sdfs_t *obj) { return 0; }
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297 | uint64_t sdfs_sectors(sdfs_t *obj) { return obj->_sectors; }
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298 |
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299 |
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300 | // PRIVATE FUNCTIONS
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301 | static int sdfs__cmd(sdfs_t *obj, int cmd, int arg)
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302 | {
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303 | gpio_write(&obj->_cs, 0);
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304 |
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305 | // send a command
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306 | spi_master_write(&obj->_spi, 0x40 | cmd);
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307 | spi_master_write(&obj->_spi, arg >> 24);
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308 | spi_master_write(&obj->_spi, arg >> 16);
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309 | spi_master_write(&obj->_spi, arg >> 8);
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310 | spi_master_write(&obj->_spi, arg >> 0);
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311 | spi_master_write(&obj->_spi, 0x95);
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312 |
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313 | // wait for the repsonse (response[7] == 0)
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314 | for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
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315 | int response = spi_master_write(&obj->_spi, 0xFF);
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316 | if (!(response & 0x80)) {
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317 | gpio_write(&obj->_cs, 1);
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318 | spi_master_write(&obj->_spi, 0xFF);
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319 | return response;
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320 | }
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321 | }
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322 | gpio_write(&obj->_cs, 1);
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323 | spi_master_write(&obj->_spi, 0xFF);
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324 | return -1; // timeout
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325 | }
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326 |
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327 | int sdfs__cmdx(sdfs_t *obj, int cmd, int arg)
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328 | {
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329 | gpio_write(&obj->_cs, 0);
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330 |
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331 | // send a command
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332 | spi_master_write(&obj->_spi, 0x40 | cmd);
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333 | spi_master_write(&obj->_spi, arg >> 24);
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334 | spi_master_write(&obj->_spi, arg >> 16);
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335 | spi_master_write(&obj->_spi, arg >> 8);
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336 | spi_master_write(&obj->_spi, arg >> 0);
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337 | spi_master_write(&obj->_spi, 0x95);
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338 |
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339 | // wait for the repsonse (response[7] == 0)
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340 | for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
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341 | int response = spi_master_write(&obj->_spi, 0xFF);
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342 | if (!(response & 0x80)) {
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343 | return response;
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344 | }
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345 | }
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346 | gpio_write(&obj->_cs, 1);
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347 | spi_master_write(&obj->_spi, 0xFF);
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348 | return -1; // timeout
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349 | }
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350 |
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351 | static int sdfs__cmd58(sdfs_t *obj)
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352 | {
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353 | gpio_write(&obj->_cs, 0);
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354 | int arg = 0;
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355 |
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356 | // send a command
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357 | spi_master_write(&obj->_spi, 0x40 | 58);
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358 | spi_master_write(&obj->_spi, arg >> 24);
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359 | spi_master_write(&obj->_spi, arg >> 16);
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360 | spi_master_write(&obj->_spi, arg >> 8);
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361 | spi_master_write(&obj->_spi, arg >> 0);
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362 | spi_master_write(&obj->_spi, 0x95);
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363 |
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364 | // wait for the repsonse (response[7] == 0)
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365 | for (int i = 0; i < SD_COMMAND_TIMEOUT; i++) {
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366 | int response = spi_master_write(&obj->_spi, 0xFF);
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367 | if (!(response & 0x80)) {
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368 | int ocr = spi_master_write(&obj->_spi, 0xFF) << 24;
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369 | ocr |= spi_master_write(&obj->_spi, 0xFF) << 16;
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370 | ocr |= spi_master_write(&obj->_spi, 0xFF) << 8;
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371 | ocr |= spi_master_write(&obj->_spi, 0xFF) << 0;
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372 | gpio_write(&obj->_cs, 1);
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373 | spi_master_write(&obj->_spi, 0xFF);
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374 | return response;
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375 | }
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376 | }
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377 | gpio_write(&obj->_cs, 1);
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378 | spi_master_write(&obj->_spi, 0xFF);
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379 | return -1; // timeout
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380 | }
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381 |
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382 | static int sdfs__cmd8(sdfs_t *obj)
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383 | {
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384 | gpio_write(&obj->_cs, 0);
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385 |
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386 | // send a command
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387 | spi_master_write(&obj->_spi, 0x40 | 8); // CMD8
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388 | spi_master_write(&obj->_spi, 0x00); // reserved
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389 | spi_master_write(&obj->_spi, 0x00); // reserved
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390 | spi_master_write(&obj->_spi, 0x01); // 3.3v
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391 | spi_master_write(&obj->_spi, 0xAA); // check pattern
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392 | spi_master_write(&obj->_spi, 0x87); // crc
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393 |
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394 | // wait for the repsonse (response[7] == 0)
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395 | for (int i = 0; i < SD_COMMAND_TIMEOUT * 1000; i++) {
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396 | char response[5];
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397 | response[0] = spi_master_write(&obj->_spi, 0xFF);
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398 | if (!(response[0] & 0x80)) {
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399 | for (int j = 1; j < 5; j++) {
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400 | response[i] = spi_master_write(&obj->_spi, 0xFF);
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401 | }
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402 | gpio_write(&obj->_cs, 1);
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403 | spi_master_write(&obj->_spi, 0xFF);
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404 | return response[0];
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405 | }
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406 | }
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407 | gpio_write(&obj->_cs, 1);
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408 | spi_master_write(&obj->_spi, 0xFF);
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409 | return -1; // timeout
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410 | }
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411 |
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412 | static int sdfs__read(sdfs_t *obj, uint8_t *buffer, uint32_t length)
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413 | {
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414 | gpio_write(&obj->_cs, 0);
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415 |
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416 | // read until start byte (0xFF)
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417 | while (spi_master_write(&obj->_spi, 0xFF) != 0xFE);
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418 |
|
---|
419 | // read data
|
---|
420 | for (int i = 0; i < length; i++) {
|
---|
421 | buffer[i] = spi_master_write(&obj->_spi, 0xFF);
|
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422 | }
|
---|
423 | spi_master_write(&obj->_spi, 0xFF); // checksum
|
---|
424 | spi_master_write(&obj->_spi, 0xFF);
|
---|
425 |
|
---|
426 | gpio_write(&obj->_cs, 1);
|
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427 | spi_master_write(&obj->_spi, 0xFF);
|
---|
428 | return 0;
|
---|
429 | }
|
---|
430 |
|
---|
431 | static int sdfs__write(sdfs_t *obj, const uint8_t*buffer, uint32_t length)
|
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432 | {
|
---|
433 | gpio_write(&obj->_cs, 0);
|
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434 |
|
---|
435 | // indicate start of block
|
---|
436 | spi_master_write(&obj->_spi, 0xFE);
|
---|
437 |
|
---|
438 | // write the data
|
---|
439 | for (int i = 0; i < length; i++) {
|
---|
440 | spi_master_write(&obj->_spi, buffer[i]);
|
---|
441 | }
|
---|
442 |
|
---|
443 | // write the checksum
|
---|
444 | spi_master_write(&obj->_spi, 0xFF);
|
---|
445 | spi_master_write(&obj->_spi, 0xFF);
|
---|
446 |
|
---|
447 | // check the response token
|
---|
448 | if ((spi_master_write(&obj->_spi, 0xFF) & 0x1F) != 0x05) {
|
---|
449 | gpio_write(&obj->_cs, 1);
|
---|
450 | spi_master_write(&obj->_spi, 0xFF);
|
---|
451 | return 1;
|
---|
452 | }
|
---|
453 |
|
---|
454 | // wait for write to finish
|
---|
455 | while (spi_master_write(&obj->_spi, 0xFF) == 0);
|
---|
456 |
|
---|
457 | gpio_write(&obj->_cs, 1);
|
---|
458 | spi_master_write(&obj->_spi, 0xFF);
|
---|
459 | return 0;
|
---|
460 | }
|
---|
461 |
|
---|
462 | static uint32_t sdfs_ext_bits(sdfs_t *obj, unsigned char *data, int msb, int lsb)
|
---|
463 | {
|
---|
464 | uint32_t bits = 0;
|
---|
465 | uint32_t size = 1 + msb - lsb;
|
---|
466 | for (uint32_t i = 0; i < size; i++) {
|
---|
467 | uint32_t position = lsb + i;
|
---|
468 | uint32_t byte = 15 - (position >> 3);
|
---|
469 | uint32_t bit = position & 0x7;
|
---|
470 | uint32_t value = (data[byte] >> bit) & 1;
|
---|
471 | bits |= value << i;
|
---|
472 | }
|
---|
473 | return bits;
|
---|
474 | }
|
---|
475 |
|
---|
476 | static uint64_t sdfs__sd_sectors(sdfs_t *obj)
|
---|
477 | {
|
---|
478 | uint32_t c_size, c_size_mult, read_bl_len;
|
---|
479 | uint32_t block_len, mult, blocknr, capacity;
|
---|
480 | uint32_t hc_c_size;
|
---|
481 | uint64_t blocks;
|
---|
482 |
|
---|
483 | // CMD9, Response R2 (R1 byte + 16-byte block read)
|
---|
484 | if (sdfs__cmdx(obj, 9, 0) != 0) {
|
---|
485 | debug("Didn't get a response from the disk\n");
|
---|
486 | return 0;
|
---|
487 | }
|
---|
488 |
|
---|
489 | uint8_t csd[16];
|
---|
490 | if (sdfs__read(obj, csd, 16) != 0) {
|
---|
491 | debug("Couldn't read csd response from disk\n");
|
---|
492 | return 0;
|
---|
493 | }
|
---|
494 |
|
---|
495 | // csd_structure : csd[127:126]
|
---|
496 | // c_size : csd[73:62]
|
---|
497 | // c_size_mult : csd[49:47]
|
---|
498 | // read_bl_len : csd[83:80] - the *maximum* read block length
|
---|
499 |
|
---|
500 | int csd_structure = sdfs_ext_bits(obj, csd, 127, 126);
|
---|
501 |
|
---|
502 | switch (csd_structure) {
|
---|
503 | case 0:
|
---|
504 | obj->cdv = 512;
|
---|
505 | c_size = sdfs_ext_bits(obj, csd, 73, 62);
|
---|
506 | c_size_mult = sdfs_ext_bits(obj, csd, 49, 47);
|
---|
507 | read_bl_len = sdfs_ext_bits(obj, csd, 83, 80);
|
---|
508 |
|
---|
509 | block_len = 1 << read_bl_len;
|
---|
510 | mult = 1 << (c_size_mult + 2);
|
---|
511 | blocknr = (c_size + 1) * mult;
|
---|
512 | capacity = blocknr * block_len;
|
---|
513 | blocks = capacity / 512;
|
---|
514 | debug_if(SD_DBG, "\n\rSDCard\n\rc_size: %d \n\rcapacity: %ld \n\rsectors: %lld\n\r", c_size, capacity, blocks);
|
---|
515 | break;
|
---|
516 |
|
---|
517 | case 1:
|
---|
518 | obj->cdv = 1;
|
---|
519 | hc_c_size = sdfs_ext_bits(obj, csd, 63, 48);
|
---|
520 | blocks = (hc_c_size + 1) * 1024;
|
---|
521 | debug_if(SD_DBG, "\n\rSDHC Card \n\rhc_c_size: %d\n\rcapacity: %lld \n\rsectors: %lld\n\r", hc_c_size, blocks * 512, blocks);
|
---|
522 | break;
|
---|
523 |
|
---|
524 | default:
|
---|
525 | debug("CSD struct unsupported\r\n");
|
---|
526 | return 0;
|
---|
527 | };
|
---|
528 | return blocks;
|
---|
529 | }
|
---|