Richard Parker
HMC6352 Library
HMC6352.cpp@2:dc4867624d5a, 2010-04-29 (annotated)
- Committer:
- richardparker
- Date:
- Thu Apr 29 19:26:30 2010 +0000
- Revision:
- 2:dc4867624d5a
- Parent:
- 1:1f500fa755c8
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| richardparker | 0:78e66010e47b | 1 | // Copyright 2009 Richard Parker |
| richardparker | 0:78e66010e47b | 2 | |
| richardparker | 0:78e66010e47b | 3 | #include "mbed.h" |
| richardparker | 0:78e66010e47b | 4 | #include "HMC6352.h" |
| richardparker | 0:78e66010e47b | 5 | |
| richardparker | 0:78e66010e47b | 6 | // Misc defines. |
| richardparker | 0:78e66010e47b | 7 | #define HMC6352_DEFAULT_ADDRESS 0x42 |
| richardparker | 0:78e66010e47b | 8 | |
| richardparker | 0:78e66010e47b | 9 | // Masks. |
| richardparker | 0:78e66010e47b | 10 | #define HMC6352_OP_MODE_MASK 0x03 |
| richardparker | 0:78e66010e47b | 11 | #define HMC6352_OP_FREQ_MASK 0x60 |
| richardparker | 0:78e66010e47b | 12 | #define HMC6352_OP_AUTO_MASK 0x10 |
| richardparker | 0:78e66010e47b | 13 | |
| richardparker | 0:78e66010e47b | 14 | // Register addresses. |
| richardparker | 0:78e66010e47b | 15 | #define HMC6352_ADDRESS_ADDRESS 0x00 |
| richardparker | 0:78e66010e47b | 16 | #define HMC6352_XO_MSB_ADDRESS 0x01 |
| richardparker | 0:78e66010e47b | 17 | #define HMC6352_XO_LSB_ADDRESS 0x02 |
| richardparker | 0:78e66010e47b | 18 | #define HMC6352_YO_MSB_ADDRESS 0x03 |
| richardparker | 0:78e66010e47b | 19 | #define HMC6352_YO_LSB_ADDRESS 0x04 |
| richardparker | 0:78e66010e47b | 20 | #define HMC6352_TIME_DELAY_ADDRESS 0x05 |
| richardparker | 0:78e66010e47b | 21 | #define HMC6352_SUMMING_ADDRESS 0x06 |
| richardparker | 0:78e66010e47b | 22 | #define HMC6352_VERSION_ADDRESS 0x07 |
| richardparker | 0:78e66010e47b | 23 | #define HMC6352_OPERATION_ADDRESS 0x08 |
| richardparker | 0:78e66010e47b | 24 | |
| richardparker | 0:78e66010e47b | 25 | #define HMC6352_OUTPUT_REGISTER 0x4E |
| richardparker | 0:78e66010e47b | 26 | #define HMC6352_OPERATION_REGISTER 0x74 |
| richardparker | 0:78e66010e47b | 27 | |
| richardparker | 0:78e66010e47b | 28 | // Commands for HMC6352. |
| richardparker | 0:78e66010e47b | 29 | #define HMC6352_WRITE_EEPROM 0x77 // 'w' |
| richardparker | 0:78e66010e47b | 30 | #define HMC6352_READ_EEPROM 0x72 // 'r' |
| richardparker | 0:78e66010e47b | 31 | #define HMC6352_WRITE_RAM 0x47 // 'G' |
| richardparker | 0:78e66010e47b | 32 | #define HMC6352_READ_RAM 0x67 // 'g' |
| richardparker | 0:78e66010e47b | 33 | #define HMC6352_WAKE_UP 0x57 // 'W' |
| richardparker | 0:78e66010e47b | 34 | #define HMC6352_SLEEP 0x53 // 'S' |
| richardparker | 0:78e66010e47b | 35 | #define HMC6352_RESET 0x4F // 'O' |
| richardparker | 0:78e66010e47b | 36 | #define HMC6352_START_CAL 0x43 // 'C' |
| richardparker | 0:78e66010e47b | 37 | #define HMC6352_END_CAL 0x45 // 'E' |
| richardparker | 0:78e66010e47b | 38 | #define HMC6352_SAVE_OPERATION 0x4C // 'L' |
| richardparker | 0:78e66010e47b | 39 | #define HMC6352_RETRIEVE_HEADING 0x41 // 'A' |
| richardparker | 0:78e66010e47b | 40 | |
| richardparker | 0:78e66010e47b | 41 | HMC6352::HMC6352(PinName sda, PinName scl) |
| richardparker | 0:78e66010e47b | 42 | : _i2c(sda, scl), |
| richardparker | 0:78e66010e47b | 43 | _address(HMC6352_DEFAULT_ADDRESS) |
| richardparker | 0:78e66010e47b | 44 | { |
| richardparker | 0:78e66010e47b | 45 | // Set the frequency of the transfers in Hz for HMC6352 is 100000 Hz. |
| richardparker | 0:78e66010e47b | 46 | _i2c.frequency(100000); |
| richardparker | 0:78e66010e47b | 47 | } |
| richardparker | 0:78e66010e47b | 48 | |
| richardparker | 0:78e66010e47b | 49 | HMC6352::~HMC6352() |
| richardparker | 0:78e66010e47b | 50 | { |
| richardparker | 0:78e66010e47b | 51 | } |
| richardparker | 0:78e66010e47b | 52 | |
| richardparker | 0:78e66010e47b | 53 | char HMC6352::getVersion() |
| richardparker | 0:78e66010e47b | 54 | { |
| richardparker | 0:78e66010e47b | 55 | // Read the version number of the chip will be above 0x00 if it |
| richardparker | 0:78e66010e47b | 56 | // is a production chip. |
| richardparker | 0:78e66010e47b | 57 | _readFromMemory(HMC6352_VERSION_ADDRESS, true); |
| richardparker | 0:78e66010e47b | 58 | return _buffer[0]; |
| richardparker | 0:78e66010e47b | 59 | } |
| richardparker | 0:78e66010e47b | 60 | |
| richardparker | 0:78e66010e47b | 61 | void HMC6352::setVersion(const char version) |
| richardparker | 0:78e66010e47b | 62 | { |
| richardparker | 0:78e66010e47b | 63 | // Write the version number to the chip. |
| richardparker | 0:78e66010e47b | 64 | _writeToMemory(HMC6352_VERSION_ADDRESS, version, true); |
| richardparker | 0:78e66010e47b | 65 | } |
| richardparker | 0:78e66010e47b | 66 | |
| richardparker | 0:78e66010e47b | 67 | char HMC6352::getTimeDelay() |
| richardparker | 0:78e66010e47b | 68 | { |
| richardparker | 0:78e66010e47b | 69 | // Read the time delay |
| richardparker | 0:78e66010e47b | 70 | _readFromMemory(HMC6352_TIME_DELAY_ADDRESS, true); |
| richardparker | 0:78e66010e47b | 71 | return _buffer[0]; |
| richardparker | 0:78e66010e47b | 72 | } |
| richardparker | 0:78e66010e47b | 73 | |
| richardparker | 0:78e66010e47b | 74 | void HMC6352::setTimeDelay(const char delay) |
| richardparker | 0:78e66010e47b | 75 | { |
| richardparker | 0:78e66010e47b | 76 | // Write the time delay to the chip. |
| richardparker | 0:78e66010e47b | 77 | _writeToMemory(HMC6352_TIME_DELAY_ADDRESS, delay, true); |
| richardparker | 0:78e66010e47b | 78 | } |
| richardparker | 0:78e66010e47b | 79 | |
| richardparker | 0:78e66010e47b | 80 | char HMC6352::getSumming() |
| richardparker | 0:78e66010e47b | 81 | { |
| richardparker | 0:78e66010e47b | 82 | // Read the number of summing samples. |
| richardparker | 0:78e66010e47b | 83 | _readFromMemory(HMC6352_SUMMING_ADDRESS, true); |
| richardparker | 0:78e66010e47b | 84 | return _buffer[0]; |
| richardparker | 0:78e66010e47b | 85 | } |
| richardparker | 0:78e66010e47b | 86 | |
| richardparker | 0:78e66010e47b | 87 | void HMC6352::setSumming(const char samples) |
| richardparker | 0:78e66010e47b | 88 | { |
| richardparker | 0:78e66010e47b | 89 | // Write the number of summing samples to the chip. |
| richardparker | 0:78e66010e47b | 90 | _writeToMemory(HMC6352_SUMMING_ADDRESS, samples, true); |
| richardparker | 0:78e66010e47b | 91 | } |
| richardparker | 0:78e66010e47b | 92 | |
| richardparker | 0:78e66010e47b | 93 | float HMC6352::getHeading() |
| richardparker | 0:78e66010e47b | 94 | { |
| richardparker | 0:78e66010e47b | 95 | // Send the retrieve heading command. |
| richardparker | 0:78e66010e47b | 96 | _buffer[0] = HMC6352_RETRIEVE_HEADING; |
| richardparker | 0:78e66010e47b | 97 | _i2c.write(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 98 | // Retrieve takes 6000us. |
| richardparker | 0:78e66010e47b | 99 | wait_us(6000); |
| richardparker | 0:78e66010e47b | 100 | |
| richardparker | 0:78e66010e47b | 101 | // As soon as the rerieve command has been sent read the result read |
| richardparker | 0:78e66010e47b | 102 | // commands only return 2 bytes. |
| richardparker | 0:78e66010e47b | 103 | _clearBuffer(); |
| richardparker | 0:78e66010e47b | 104 | _i2c.read(this->address(), _buffer, 2); |
| richardparker | 0:78e66010e47b | 105 | |
| richardparker | 0:78e66010e47b | 106 | return _bufferToHeading(); |
| richardparker | 0:78e66010e47b | 107 | } |
| richardparker | 0:78e66010e47b | 108 | |
| richardparker | 0:78e66010e47b | 109 | HMC6352::Mode HMC6352::getMode() |
| richardparker | 0:78e66010e47b | 110 | { |
| richardparker | 0:78e66010e47b | 111 | // Read the operation mode. |
| richardparker | 0:78e66010e47b | 112 | _readFromMemory(HMC6352_OPERATION_REGISTER, false); |
| richardparker | 0:78e66010e47b | 113 | |
| richardparker | 0:78e66010e47b | 114 | // Buffer now contains the op mode register, mask to get values. |
| richardparker | 0:78e66010e47b | 115 | int opmode = _buffer[0]; |
| richardparker | 0:78e66010e47b | 116 | opmode = opmode & HMC6352_OP_MODE_MASK; |
| richardparker | 0:78e66010e47b | 117 | |
| richardparker | 0:78e66010e47b | 118 | // Convert the value into the mode. |
| richardparker | 0:78e66010e47b | 119 | switch (opmode) |
| richardparker | 0:78e66010e47b | 120 | { |
| richardparker | 0:78e66010e47b | 121 | case 0x0: |
| richardparker | 0:78e66010e47b | 122 | return HMC6352::Standby; |
| richardparker | 0:78e66010e47b | 123 | case 0x1: |
| richardparker | 0:78e66010e47b | 124 | return HMC6352::Query; |
| richardparker | 0:78e66010e47b | 125 | case 0x2: |
| richardparker | 0:78e66010e47b | 126 | return HMC6352::Continuous; |
| richardparker | 0:78e66010e47b | 127 | default: |
| richardparker | 0:78e66010e47b | 128 | return HMC6352::None; |
| richardparker | 0:78e66010e47b | 129 | } |
| richardparker | 0:78e66010e47b | 130 | } |
| richardparker | 0:78e66010e47b | 131 | |
| richardparker | 0:78e66010e47b | 132 | void HMC6352::setMode(HMC6352::Mode mode) |
| richardparker | 0:78e66010e47b | 133 | { |
| richardparker | 0:78e66010e47b | 134 | _readFromMemory(HMC6352_OPERATION_REGISTER, false); |
| richardparker | 0:78e66010e47b | 135 | |
| richardparker | 0:78e66010e47b | 136 | switch (mode) |
| richardparker | 0:78e66010e47b | 137 | { |
| richardparker | 0:78e66010e47b | 138 | case HMC6352::Standby: |
| richardparker | 0:78e66010e47b | 139 | _writeToMemory(HMC6352_OPERATION_REGISTER, (_buffer[0] & 0xFC) | 0x0, false); |
| richardparker | 0:78e66010e47b | 140 | break; |
| richardparker | 0:78e66010e47b | 141 | case HMC6352::Query: |
| richardparker | 0:78e66010e47b | 142 | _writeToMemory(HMC6352_OPERATION_REGISTER, (_buffer[0] & 0xFC) | 0x1, false); |
| richardparker | 0:78e66010e47b | 143 | break; |
| richardparker | 0:78e66010e47b | 144 | case HMC6352::Continuous: |
| richardparker | 0:78e66010e47b | 145 | _writeToMemory(HMC6352_OPERATION_REGISTER, (_buffer[0] & 0xFC) | 0x2, false); |
| richardparker | 0:78e66010e47b | 146 | break; |
| richardparker | 0:78e66010e47b | 147 | default: |
| richardparker | 0:78e66010e47b | 148 | return; |
| richardparker | 0:78e66010e47b | 149 | } |
| richardparker | 0:78e66010e47b | 150 | } |
| richardparker | 0:78e66010e47b | 151 | |
| richardparker | 0:78e66010e47b | 152 | HMC6352::Output HMC6352::getOutput() |
| richardparker | 0:78e66010e47b | 153 | { |
| richardparker | 0:78e66010e47b | 154 | // Read the output mode from RAM |
| richardparker | 0:78e66010e47b | 155 | _readFromMemory(HMC6352_OUTPUT_REGISTER, false); |
| richardparker | 0:78e66010e47b | 156 | |
| richardparker | 0:78e66010e47b | 157 | // Buffer now contains the output register. |
| richardparker | 0:78e66010e47b | 158 | int output = _buffer[0]; |
| richardparker | 0:78e66010e47b | 159 | |
| richardparker | 0:78e66010e47b | 160 | // Convert the value into the mode. |
| richardparker | 0:78e66010e47b | 161 | switch (output) |
| richardparker | 0:78e66010e47b | 162 | { |
| richardparker | 0:78e66010e47b | 163 | case 0x0: |
| richardparker | 0:78e66010e47b | 164 | return HMC6352::Heading; |
| richardparker | 0:78e66010e47b | 165 | case 0x1: |
| richardparker | 0:78e66010e47b | 166 | return HMC6352::RawX; |
| richardparker | 0:78e66010e47b | 167 | case 0x2: |
| richardparker | 0:78e66010e47b | 168 | return HMC6352::RawY; |
| richardparker | 0:78e66010e47b | 169 | case 0x3: |
| richardparker | 0:78e66010e47b | 170 | return HMC6352::X; |
| richardparker | 0:78e66010e47b | 171 | case 0x4: |
| richardparker | 0:78e66010e47b | 172 | return HMC6352::Y; |
| richardparker | 0:78e66010e47b | 173 | default: |
| richardparker | 0:78e66010e47b | 174 | return HMC6352::Unknown; |
| richardparker | 0:78e66010e47b | 175 | } |
| richardparker | 0:78e66010e47b | 176 | } |
| richardparker | 0:78e66010e47b | 177 | |
| richardparker | 0:78e66010e47b | 178 | void HMC6352::setOutput(HMC6352::Output output) |
| richardparker | 0:78e66010e47b | 179 | { |
| richardparker | 0:78e66010e47b | 180 | switch (output) |
| richardparker | 0:78e66010e47b | 181 | { |
| richardparker | 0:78e66010e47b | 182 | case HMC6352::Heading: |
| richardparker | 0:78e66010e47b | 183 | _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x0, false); |
| richardparker | 0:78e66010e47b | 184 | break; |
| richardparker | 0:78e66010e47b | 185 | case HMC6352::RawX: |
| richardparker | 0:78e66010e47b | 186 | _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x1, false); |
| richardparker | 0:78e66010e47b | 187 | break; |
| richardparker | 0:78e66010e47b | 188 | case HMC6352::RawY: |
| richardparker | 0:78e66010e47b | 189 | _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x2, false); |
| richardparker | 0:78e66010e47b | 190 | break; |
| richardparker | 0:78e66010e47b | 191 | case HMC6352::X: |
| richardparker | 0:78e66010e47b | 192 | _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x3, false); |
| richardparker | 0:78e66010e47b | 193 | break; |
| richardparker | 0:78e66010e47b | 194 | case HMC6352::Y: |
| richardparker | 0:78e66010e47b | 195 | _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x4, false); |
| richardparker | 0:78e66010e47b | 196 | break; |
| richardparker | 0:78e66010e47b | 197 | default: |
| richardparker | 0:78e66010e47b | 198 | return; |
| richardparker | 0:78e66010e47b | 199 | } |
| richardparker | 0:78e66010e47b | 200 | } |
| richardparker | 0:78e66010e47b | 201 | |
| richardparker | 0:78e66010e47b | 202 | void HMC6352::calibrate(int delay) |
| richardparker | 0:78e66010e47b | 203 | { |
| richardparker | 1:1f500fa755c8 | 204 | startCalibrate(); |
| richardparker | 1:1f500fa755c8 | 205 | |
| richardparker | 1:1f500fa755c8 | 206 | // Now wait an optimal 20s in which two full turns should be |
| richardparker | 1:1f500fa755c8 | 207 | // made of the compass to gather enough data, see page 7 of |
| richardparker | 1:1f500fa755c8 | 208 | // the data sheet. |
| richardparker | 1:1f500fa755c8 | 209 | wait(delay); |
| richardparker | 1:1f500fa755c8 | 210 | |
| richardparker | 1:1f500fa755c8 | 211 | endCalibrate(); |
| richardparker | 1:1f500fa755c8 | 212 | } |
| richardparker | 1:1f500fa755c8 | 213 | |
| richardparker | 1:1f500fa755c8 | 214 | void HMC6352::startCalibrate() |
| richardparker | 1:1f500fa755c8 | 215 | { |
| richardparker | 0:78e66010e47b | 216 | // Send the enter calibrate command. |
| richardparker | 0:78e66010e47b | 217 | _buffer[0] = HMC6352_START_CAL; |
| richardparker | 0:78e66010e47b | 218 | _i2c.write(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 219 | // Enter takes 10us. |
| richardparker | 0:78e66010e47b | 220 | wait_us(10); |
| richardparker | 1:1f500fa755c8 | 221 | } |
| richardparker | 1:1f500fa755c8 | 222 | |
| richardparker | 1:1f500fa755c8 | 223 | void HMC6352::endCalibrate() |
| richardparker | 1:1f500fa755c8 | 224 | { |
| richardparker | 0:78e66010e47b | 225 | // Send the exit calibrate command. |
| richardparker | 0:78e66010e47b | 226 | _buffer[0] = HMC6352_END_CAL; |
| richardparker | 0:78e66010e47b | 227 | _i2c.write(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 228 | // Enter takes 14000us. |
| richardparker | 0:78e66010e47b | 229 | wait_us(14000); |
| richardparker | 0:78e66010e47b | 230 | } |
| richardparker | 0:78e66010e47b | 231 | |
| richardparker | 0:78e66010e47b | 232 | void HMC6352::saveOperation() |
| richardparker | 0:78e66010e47b | 233 | { |
| richardparker | 0:78e66010e47b | 234 | // Send the enter calibrate command. |
| richardparker | 0:78e66010e47b | 235 | _buffer[0] = HMC6352_SAVE_OPERATION; |
| richardparker | 0:78e66010e47b | 236 | _i2c.write(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 237 | // Save takes 125us. |
| richardparker | 0:78e66010e47b | 238 | wait_us(125); |
| richardparker | 0:78e66010e47b | 239 | } |
| richardparker | 0:78e66010e47b | 240 | |
| richardparker | 0:78e66010e47b | 241 | void HMC6352::reset() |
| richardparker | 0:78e66010e47b | 242 | { |
| richardparker | 0:78e66010e47b | 243 | // Send the reset command. |
| richardparker | 0:78e66010e47b | 244 | _buffer[0] = HMC6352_RESET; |
| richardparker | 0:78e66010e47b | 245 | _i2c.write(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 246 | // Reset takes 6000us. |
| richardparker | 0:78e66010e47b | 247 | wait_us(6000); |
| richardparker | 0:78e66010e47b | 248 | } |
| richardparker | 0:78e66010e47b | 249 | |
| richardparker | 0:78e66010e47b | 250 | void HMC6352::wakeUp() |
| richardparker | 0:78e66010e47b | 251 | { |
| richardparker | 0:78e66010e47b | 252 | // Send the wakeup command. |
| richardparker | 0:78e66010e47b | 253 | _buffer[0] = HMC6352_WAKE_UP; |
| richardparker | 0:78e66010e47b | 254 | _i2c.write(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 255 | wait_us(100); |
| richardparker | 0:78e66010e47b | 256 | } |
| richardparker | 0:78e66010e47b | 257 | |
| richardparker | 0:78e66010e47b | 258 | void HMC6352::goToSleep() |
| richardparker | 0:78e66010e47b | 259 | { |
| richardparker | 0:78e66010e47b | 260 | // Send the reset command. |
| richardparker | 0:78e66010e47b | 261 | _buffer[0] = HMC6352_SLEEP; |
| richardparker | 0:78e66010e47b | 262 | _i2c.write(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 263 | wait_us(10); |
| richardparker | 0:78e66010e47b | 264 | } |
| richardparker | 0:78e66010e47b | 265 | |
| richardparker | 0:78e66010e47b | 266 | void HMC6352::_readFromMemory(const char address, const bool eeprom) |
| richardparker | 0:78e66010e47b | 267 | { |
| richardparker | 0:78e66010e47b | 268 | char command; |
| richardparker | 0:78e66010e47b | 269 | |
| richardparker | 0:78e66010e47b | 270 | // Decide what the command should be (either read from eeprom or |
| richardparker | 0:78e66010e47b | 271 | // currently loaded memory). |
| richardparker | 0:78e66010e47b | 272 | if (eeprom == true) |
| richardparker | 0:78e66010e47b | 273 | { |
| richardparker | 0:78e66010e47b | 274 | command = HMC6352_READ_EEPROM; |
| richardparker | 0:78e66010e47b | 275 | } else { |
| richardparker | 0:78e66010e47b | 276 | command = HMC6352_READ_RAM; |
| richardparker | 0:78e66010e47b | 277 | } |
| richardparker | 0:78e66010e47b | 278 | |
| richardparker | 0:78e66010e47b | 279 | // Send the read command to the current address (commands are always |
| richardparker | 0:78e66010e47b | 280 | // two bytes long). |
| richardparker | 0:78e66010e47b | 281 | _buffer[0] = command; |
| richardparker | 0:78e66010e47b | 282 | _buffer[1] = address; |
| richardparker | 0:78e66010e47b | 283 | _i2c.write(this->address(), _buffer, 2); |
| richardparker | 0:78e66010e47b | 284 | wait_us(70); |
| richardparker | 0:78e66010e47b | 285 | |
| richardparker | 0:78e66010e47b | 286 | // As soon as the read command has been sent read the result read |
| richardparker | 0:78e66010e47b | 287 | // commands only return 1 byte. |
| richardparker | 0:78e66010e47b | 288 | _clearBuffer(); |
| richardparker | 0:78e66010e47b | 289 | _i2c.read(this->address(), _buffer, 1); |
| richardparker | 0:78e66010e47b | 290 | } |
| richardparker | 0:78e66010e47b | 291 | |
| richardparker | 0:78e66010e47b | 292 | void HMC6352::_writeToMemory(const char address, const char data, const bool eeprom) |
| richardparker | 0:78e66010e47b | 293 | { |
| richardparker | 0:78e66010e47b | 294 | char command; |
| richardparker | 0:78e66010e47b | 295 | |
| richardparker | 0:78e66010e47b | 296 | // Decide what the command should be (either write to eeprom or |
| richardparker | 0:78e66010e47b | 297 | // currently loaded memory). |
| richardparker | 0:78e66010e47b | 298 | if (eeprom == true) |
| richardparker | 0:78e66010e47b | 299 | { |
| richardparker | 0:78e66010e47b | 300 | command = HMC6352_WRITE_EEPROM; |
| richardparker | 0:78e66010e47b | 301 | } else { |
| richardparker | 0:78e66010e47b | 302 | command = HMC6352_WRITE_RAM; |
| richardparker | 0:78e66010e47b | 303 | } |
| richardparker | 0:78e66010e47b | 304 | |
| richardparker | 0:78e66010e47b | 305 | // Send the write data to the current address (commands are always |
| richardparker | 0:78e66010e47b | 306 | // three bytes long). |
| richardparker | 0:78e66010e47b | 307 | _buffer[0] = command; |
| richardparker | 0:78e66010e47b | 308 | _buffer[1] = address; |
| richardparker | 0:78e66010e47b | 309 | _buffer[2] = data; |
| richardparker | 0:78e66010e47b | 310 | _i2c.write(this->address(), _buffer, 3); |
| richardparker | 0:78e66010e47b | 311 | wait_us(70); |
| richardparker | 0:78e66010e47b | 312 | } |
| richardparker | 0:78e66010e47b | 313 | |
| richardparker | 0:78e66010e47b | 314 | void HMC6352::_clearBuffer() |
| richardparker | 0:78e66010e47b | 315 | { |
| richardparker | 0:78e66010e47b | 316 | // Set both buffer bytes to null. |
| richardparker | 0:78e66010e47b | 317 | _buffer[0] = 0x0; |
| richardparker | 0:78e66010e47b | 318 | _buffer[1] = 0x0; |
| richardparker | 0:78e66010e47b | 319 | _buffer[2] = 0x0; |
| richardparker | 0:78e66010e47b | 320 | } |
| richardparker | 0:78e66010e47b | 321 | |
| richardparker | 0:78e66010e47b | 322 | float HMC6352::_bufferToHeading() |
| richardparker | 0:78e66010e47b | 323 | { |
| richardparker | 0:78e66010e47b | 324 | // The heading is returned as a 16 bit number with the msb in the first |
| richardparker | 0:78e66010e47b | 325 | // byte and the lsb in the next byte. |
| richardparker | 0:78e66010e47b | 326 | return (((_buffer[0] << 8) + _buffer[1])/10.0); |
| richardparker | 0:78e66010e47b | 327 | } |