| Line | Branch | Decision | Exec | Source |
|---|---|---|---|---|
| 1 | /** | |||
| 2 | * @file i2c_bb.cpp | |||
| 3 | * @brief Bit-banged I2C driver | |||
| 4 | * | |||
| 5 | * @date February 6, 2020 | |||
| 6 | * @author Matthew Kennedy, (c) 2020 | |||
| 7 | */ | |||
| 8 | ||||
| 9 | #include "pch.h" | |||
| 10 | ||||
| 11 | #include "i2c_bb.h" | |||
| 12 | ||||
| 13 | 46 | void BitbangI2c::sda_high() { | ||
| 14 | #if EFI_PROD_CODE | |||
| 15 | palSetPad(m_sdaPort, m_sdaPin); | |||
| 16 | #endif | |||
| 17 | 46 | } | ||
| 18 | ||||
| 19 | 30 | void BitbangI2c::sda_low() { | ||
| 20 | #if EFI_PROD_CODE | |||
| 21 | palClearPad(m_sdaPort, m_sdaPin); | |||
| 22 | #endif | |||
| 23 | 30 | } | ||
| 24 | ||||
| 25 | 82 | void BitbangI2c::scl_high() { | ||
| 26 | #if EFI_PROD_CODE | |||
| 27 | palSetPad(m_sclPort, m_sclPin); | |||
| 28 | #endif | |||
| 29 | 82 | } | ||
| 30 | ||||
| 31 | 80 | void BitbangI2c::scl_low() { | ||
| 32 | #if EFI_PROD_CODE | |||
| 33 | palClearPad(m_sclPort, m_sclPin); | |||
| 34 | #endif | |||
| 35 | 80 | } | ||
| 36 | ||||
| 37 | 2 | bool BitbangI2c::init(brain_pin_e scl, brain_pin_e sda) { | ||
| 38 | #if EFI_PROD_CODE | |||
| 39 | if (m_sdaPort) { | |||
| 40 | return false; | |||
| 41 | } | |||
| 42 | ||||
| 43 | if (!isBrainPinValid(scl) || !isBrainPinValid(sda)) { | |||
| 44 | return false; | |||
| 45 | } | |||
| 46 | ||||
| 47 | efiSetPadMode("i2c", scl, PAL_MODE_OUTPUT_OPENDRAIN); //PAL_STM32_OTYPE_OPENDRAIN | |||
| 48 | efiSetPadMode("i2c", sda, PAL_MODE_OUTPUT_OPENDRAIN); | |||
| 49 | ||||
| 50 | m_sclPort = getHwPort("i2c", scl); | |||
| 51 | m_sclPin = getHwPin("i2c", scl); | |||
| 52 | ||||
| 53 | m_sdaPort = getHwPort("i2c", sda); | |||
| 54 | m_sdaPin = getHwPin("i2c", sda); | |||
| 55 | #endif | |||
| 56 | ||||
| 57 | // Both lines idle high | |||
| 58 | 2 | scl_high(); | ||
| 59 | 2 | sda_high(); | ||
| 60 | ||||
| 61 | 2 | return true; | ||
| 62 | } | |||
| 63 | ||||
| 64 | ✗ | void BitbangI2c::deinit() { | ||
| 65 | #if EFI_PROD_CODE | |||
| 66 | if (m_sclPort) { | |||
| 67 | gpio_pin_markUnused(m_sclPort, m_sclPin); | |||
| 68 | m_sclPort = NULL; | |||
| 69 | } | |||
| 70 | if (m_sdaPort) { | |||
| 71 | gpio_pin_markUnused(m_sdaPort, m_sdaPin); | |||
| 72 | m_sdaPort = NULL; | |||
| 73 | } | |||
| 74 | #endif | |||
| 75 | ✗ | } | ||
| 76 | ||||
| 77 | 4 | void BitbangI2c::start() { | ||
| 78 | // Start with both lines high (bus idle) | |||
| 79 | 4 | sda_high(); | ||
| 80 | 4 | waitQuarterBit(); | ||
| 81 | 4 | scl_high(); | ||
| 82 | 4 | waitQuarterBit(); | ||
| 83 | ||||
| 84 | // SDA goes low while SCL is high | |||
| 85 | 4 | sda_low(); | ||
| 86 | 4 | waitQuarterBit(); | ||
| 87 | 4 | scl_low(); | ||
| 88 | 4 | waitQuarterBit(); | ||
| 89 | 4 | } | ||
| 90 | ||||
| 91 | 4 | void BitbangI2c::stop() { | ||
| 92 | 4 | scl_low(); | ||
| 93 | 4 | waitQuarterBit(); | ||
| 94 | 4 | sda_low(); | ||
| 95 | 4 | waitQuarterBit(); | ||
| 96 | 4 | scl_high(); | ||
| 97 | 4 | waitQuarterBit(); | ||
| 98 | // SDA goes high while SCL is high | |||
| 99 | 4 | sda_high(); | ||
| 100 | 4 | } | ||
| 101 | ||||
| 102 | 50 | void BitbangI2c::sendBit(bool val) { | ||
| 103 | 50 | waitQuarterBit(); | ||
| 104 | ||||
| 105 | // Write the bit (write while SCL is low) | |||
| 106 |
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50 | if (val) { |
| 107 | 28 | sda_high(); | ||
| 108 | } else { | |||
| 109 | 22 | sda_low(); | ||
| 110 | } | |||
| 111 | ||||
| 112 | // Data setup time (~100ns min) | |||
| 113 | 50 | waitQuarterBit(); | ||
| 114 | ||||
| 115 | // Strobe the clock | |||
| 116 | 50 | scl_high(); | ||
| 117 | 50 | waitQuarterBit(); | ||
| 118 | 50 | scl_low(); | ||
| 119 | 50 | waitQuarterBit(); | ||
| 120 | 50 | } | ||
| 121 | ||||
| 122 | 22 | bool BitbangI2c::readBit() { | ||
| 123 | 22 | waitQuarterBit(); | ||
| 124 | ||||
| 125 | 22 | scl_high(); | ||
| 126 | ||||
| 127 | 22 | waitQuarterBit(); | ||
| 128 | 22 | waitQuarterBit(); | ||
| 129 | ||||
| 130 | #if EFI_PROD_CODE | |||
| 131 | // Read just before we set the clock low (ie, as late as possible) | |||
| 132 | bool val = palReadPad(m_sdaPort, m_sdaPin); | |||
| 133 | #else | |||
| 134 | 22 | bool val = false; | ||
| 135 | #endif | |||
| 136 | ||||
| 137 | 22 | scl_low(); | ||
| 138 | 22 | waitQuarterBit(); | ||
| 139 | ||||
| 140 | 22 | return val; | ||
| 141 | } | |||
| 142 | ||||
| 143 | 6 | bool BitbangI2c::writeByte(uint8_t data) { | ||
| 144 | // write out 8 data bits | |||
| 145 |
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54 | for (size_t i = 0; i < 8; i++) { |
| 146 | // Send the MSB | |||
| 147 | 48 | sendBit((data & 0x80) != 0); | ||
| 148 | ||||
| 149 | 48 | data = data << 1; | ||
| 150 | } | |||
| 151 | ||||
| 152 | // Force a release of the data line so the slave can ACK | |||
| 153 | 6 | sda_high(); | ||
| 154 | ||||
| 155 | // Read the ack bit | |||
| 156 | 6 | bool ackBit = readBit(); | ||
| 157 | ||||
| 158 | // 0 -> ack | |||
| 159 | // 1 -> nack | |||
| 160 | 6 | return !ackBit; | ||
| 161 | } | |||
| 162 | ||||
| 163 | 2 | uint8_t BitbangI2c::readByte(bool ack) { | ||
| 164 | 2 | uint8_t result = 0; | ||
| 165 | ||||
| 166 | // Read in 8 data bits | |||
| 167 |
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18 | for (size_t i = 0; i < 8; i++) { |
| 168 | 16 | result = result << 1; | ||
| 169 | ||||
| 170 |
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16 | result |= readBit() ? 1 : 0; | |
| 171 | } | |||
| 172 | ||||
| 173 | // 0 -> ack | |||
| 174 | // 1 -> nack | |||
| 175 | 2 | sendBit(!ack); | ||
| 176 | ||||
| 177 | // release SDA | |||
| 178 | 2 | sda_high(); | ||
| 179 | ||||
| 180 | 2 | return result; | ||
| 181 | } | |||
| 182 | ||||
| 183 | 316 | void BitbangI2c::waitQuarterBit() { | ||
| 184 | // This yields a bitrate of about 320khz on a 168MHz F4 | |||
| 185 |
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9796 | for (size_t i = 0; i < 30; i++) { |
| 186 | 9480 | __asm__ volatile ("nop"); | ||
| 187 | } | |||
| 188 | 316 | } | ||
| 189 | ||||
| 190 | 2 | void BitbangI2c::write(uint8_t addr, const uint8_t* writeData, size_t writeSize) { | ||
| 191 | 2 | start(); | ||
| 192 | ||||
| 193 | // Address + write | |||
| 194 | 2 | writeByte(addr << 1 | 0); | ||
| 195 | ||||
| 196 | // Write outbound bytes | |||
| 197 |
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4 | for (size_t i = 0; i < writeSize; i++) { |
| 198 | 2 | writeByte(writeData[i]); | ||
| 199 | } | |||
| 200 | ||||
| 201 | 2 | stop(); | ||
| 202 | 2 | } | ||
| 203 | ||||
| 204 | 2 | void BitbangI2c::writeRead(uint8_t addr, const uint8_t* writeData, size_t writeSize, uint8_t* readData, size_t readSize) { | ||
| 205 | 2 | write(addr, writeData, writeSize); | ||
| 206 | ||||
| 207 | 2 | read(addr, readData, readSize); | ||
| 208 | 2 | } | ||
| 209 | ||||
| 210 | 2 | void BitbangI2c::read(uint8_t addr, uint8_t* readData, size_t readSize) { | ||
| 211 | 2 | start(); | ||
| 212 | ||||
| 213 | // Address + read | |||
| 214 | 2 | writeByte(addr << 1 | 1); | ||
| 215 | ||||
| 216 |
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2 | for (size_t i = 0; i < readSize - 1; i++) { |
| 217 | // All but the last byte send ACK to indicate we're still reading | |||
| 218 | ✗ | readData[i] = readByte(true); | ||
| 219 | } | |||
| 220 | ||||
| 221 | // last byte sends NAK to indicate we're done reading | |||
| 222 | 2 | readData[readSize - 1] = readByte(false); | ||
| 223 | ||||
| 224 | 2 | stop(); | ||
| 225 | 2 | } | ||
| 226 | ||||
| 227 | 2 | uint8_t BitbangI2c::readRegister(uint8_t addr, uint8_t reg) { | ||
| 228 | 2 | uint8_t retval; | ||
| 229 | ||||
| 230 |
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2 | writeRead(addr, ®, 1, &retval, 1); | |
| 231 | ||||
| 232 | 2 | return retval; | ||
| 233 | } | |||
| 234 | ||||
| 235 | ✗ | void BitbangI2c::writeRegister(uint8_t addr, uint8_t reg, uint8_t val) { | ||
| 236 | ✗ | uint8_t buf[2]; | ||
| 237 | ✗ | buf[0] = reg; | ||
| 238 | ✗ | buf[1] = val; | ||
| 239 | ||||
| 240 | ✗ | write(addr, buf, 2); | ||
| 241 | ✗ | } | ||
| 242 |