Library for SPI communication with the AMS AS5048 rotary sensor
Dependents: heros_leg_readout_torque_addition heros_leg_readout_torque_addition heros_leg_readout_torque_addition_V3
As5048.h@3:579e12eda4e6, 2016-08-23 (annotated)
- Committer:
- megrootens
- Date:
- Tue Aug 23 15:09:35 2016 +0000
- Revision:
- 3:579e12eda4e6
- Parent:
- 2:111641f7e672
- Child:
- 4:56d59ce73270
moved const values outside class to static const within class; move enums that define commands within class
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
megrootens | 0:723d48642d5c | 1 | #ifndef _AS5048_H_ |
megrootens | 0:723d48642d5c | 2 | #define _AS5048_H_ |
megrootens | 0:723d48642d5c | 3 | |
megrootens | 0:723d48642d5c | 4 | #include "mbed.h" |
megrootens | 0:723d48642d5c | 5 | /** |
megrootens | 0:723d48642d5c | 6 | * Interfacing with the AMS AS5048A magnetic rotary sensor using SPI protocol |
megrootens | 0:723d48642d5c | 7 | * AS5048 uses 16-bit transfer; |
megrootens | 0:723d48642d5c | 8 | * We use two 8-bit transfers for compatibility with 8-bit SPI master devices |
megrootens | 0:723d48642d5c | 9 | * SPI protocol: |
megrootens | 0:723d48642d5c | 10 | * Mode = 1: |
megrootens | 0:723d48642d5c | 11 | * clock polarity = 0 --> clock pulse is high |
megrootens | 0:723d48642d5c | 12 | * clock phase = 1 --> sample on falling edge of clock pulse |
megrootens | 0:723d48642d5c | 13 | * Code was succesfully tested on the FRDM KL25Z and K22F. The same code fails |
megrootens | 0:723d48642d5c | 14 | * on the K64F for some reason. Sampling using a logic analyzer does however |
megrootens | 0:723d48642d5c | 15 | * show the same results for al three boards. |
megrootens | 0:723d48642d5c | 16 | */ |
megrootens | 0:723d48642d5c | 17 | class As5048 { |
megrootens | 0:723d48642d5c | 18 | |
megrootens | 3:579e12eda4e6 | 19 | |
megrootens | 0:723d48642d5c | 20 | public: |
megrootens | 0:723d48642d5c | 21 | |
megrootens | 3:579e12eda4e6 | 22 | // AS5048 flags |
megrootens | 3:579e12eda4e6 | 23 | typedef enum { |
megrootens | 3:579e12eda4e6 | 24 | AS_FLAG_PARITY = 0x8000, |
megrootens | 3:579e12eda4e6 | 25 | AS_FLAG_READ = 0x4000, |
megrootens | 3:579e12eda4e6 | 26 | } As5048Flag; |
megrootens | 3:579e12eda4e6 | 27 | |
megrootens | 3:579e12eda4e6 | 28 | // AS5048 commands |
megrootens | 3:579e12eda4e6 | 29 | typedef enum { |
megrootens | 3:579e12eda4e6 | 30 | AS_CMD_NOP = 0x0000, |
megrootens | 3:579e12eda4e6 | 31 | AS_CMD_ERROR = 0x0001 | AS_FLAG_READ, // Reads error register of sensor and clear error flags |
megrootens | 3:579e12eda4e6 | 32 | AS_CMD_DIAGNOSTICS = 0x3FFD | AS_FLAG_READ, // Reads automatic gain control and diagnostics info |
megrootens | 3:579e12eda4e6 | 33 | AS_CMD_MAGNITUDE = 0x3FFE | AS_FLAG_READ, |
megrootens | 3:579e12eda4e6 | 34 | AS_CMD_ANGLE = 0x3FFF | AS_FLAG_PARITY | AS_FLAG_READ, |
megrootens | 3:579e12eda4e6 | 35 | } As5048Command; |
megrootens | 3:579e12eda4e6 | 36 | |
megrootens | 3:579e12eda4e6 | 37 | // AS5048 diagnostics |
megrootens | 3:579e12eda4e6 | 38 | typedef enum { |
megrootens | 3:579e12eda4e6 | 39 | AS_DIAG_CORDIC_OVERFLOW = 0x0200, |
megrootens | 3:579e12eda4e6 | 40 | AS_DIAG_HIGH_MAGNETIC = 0x0400, |
megrootens | 3:579e12eda4e6 | 41 | AS_DIAG_LOW_MAGNETIC = 0x0800, |
megrootens | 3:579e12eda4e6 | 42 | } As5048Diagnostics; |
megrootens | 3:579e12eda4e6 | 43 | |
megrootens | 0:723d48642d5c | 44 | /** |
megrootens | 0:723d48642d5c | 45 | * Creates an object of num_sensors daisy chained AS5048 sensors; |
megrootens | 0:723d48642d5c | 46 | * default number of sensors in chain is 1 |
megrootens | 0:723d48642d5c | 47 | * @param mosi: pinname of the mosi pin of the spi communication |
megrootens | 0:723d48642d5c | 48 | * @param miso: pinname of the miso pin of the spi communication |
megrootens | 0:723d48642d5c | 49 | * @param sck: pinname of the clock pin of the spi communication |
megrootens | 0:723d48642d5c | 50 | * @param cs: pinname of the chip select pin of the spi communication |
megrootens | 0:723d48642d5c | 51 | * @param num_sensors = 1: number of sensors in daisy chain |
megrootens | 0:723d48642d5c | 52 | */ |
megrootens | 0:723d48642d5c | 53 | As5048(PinName mosi, PinName miso, PinName sck, PinName cs, int num_sensors = 1): |
megrootens | 0:723d48642d5c | 54 | kNumSensors_(num_sensors), |
megrootens | 0:723d48642d5c | 55 | chip_(cs), |
megrootens | 0:723d48642d5c | 56 | spi_(mosi, miso, sck) |
megrootens | 0:723d48642d5c | 57 | { |
megrootens | 0:723d48642d5c | 58 | DeselectChip(); |
megrootens | 0:723d48642d5c | 59 | |
megrootens | 0:723d48642d5c | 60 | spi_.format(kSpiBitsPerTransfer, kSpiMode); |
megrootens | 0:723d48642d5c | 61 | spi_.frequency(kSpiFrequency); |
megrootens | 0:723d48642d5c | 62 | |
megrootens | 0:723d48642d5c | 63 | read_buffer_ = new uint16_t[kNumSensors_]; |
megrootens | 0:723d48642d5c | 64 | angle_buffer_ = new uint16_t[kNumSensors_]; |
megrootens | 0:723d48642d5c | 65 | angle_offset_ = new uint16_t[kNumSensors_]; |
megrootens | 1:94b48453d13a | 66 | directions_ = new bool[kNumSensors_]; |
megrootens | 0:723d48642d5c | 67 | |
megrootens | 0:723d48642d5c | 68 | for (int i=0; i<kNumSensors_; ++i) { |
megrootens | 0:723d48642d5c | 69 | read_buffer_[i] = 0; |
megrootens | 0:723d48642d5c | 70 | angle_buffer_[i] = 0; |
megrootens | 0:723d48642d5c | 71 | angle_offset_[i] = 0; |
megrootens | 1:94b48453d13a | 72 | directions_[i] = true; |
megrootens | 0:723d48642d5c | 73 | } |
megrootens | 0:723d48642d5c | 74 | |
megrootens | 0:723d48642d5c | 75 | last_command_ = AS_CMD_NOP; |
megrootens | 0:723d48642d5c | 76 | } |
megrootens | 0:723d48642d5c | 77 | |
megrootens | 0:723d48642d5c | 78 | |
megrootens | 0:723d48642d5c | 79 | /** |
megrootens | 0:723d48642d5c | 80 | * Destructor, memory deallocation |
megrootens | 0:723d48642d5c | 81 | */ |
megrootens | 2:111641f7e672 | 82 | ~As5048() |
megrootens | 2:111641f7e672 | 83 | { |
megrootens | 0:723d48642d5c | 84 | delete [] read_buffer_; |
megrootens | 0:723d48642d5c | 85 | delete [] angle_buffer_; |
megrootens | 0:723d48642d5c | 86 | delete [] angle_offset_; |
megrootens | 1:94b48453d13a | 87 | delete [] directions_; |
megrootens | 0:723d48642d5c | 88 | } |
megrootens | 0:723d48642d5c | 89 | |
megrootens | 0:723d48642d5c | 90 | /** |
megrootens | 0:723d48642d5c | 91 | * Parity check |
megrootens | 0:723d48642d5c | 92 | * @param n: integer to check |
megrootens | 0:723d48642d5c | 93 | * @return: true if ok |
megrootens | 0:723d48642d5c | 94 | */ |
megrootens | 2:111641f7e672 | 95 | static bool CheckParity(int n) |
megrootens | 2:111641f7e672 | 96 | { |
megrootens | 0:723d48642d5c | 97 | int parity = n; |
megrootens | 0:723d48642d5c | 98 | for(int i=1; i <= kNumSensorBits+1; ++i) { |
megrootens | 0:723d48642d5c | 99 | n >>= 1; |
megrootens | 0:723d48642d5c | 100 | parity ^= n; |
megrootens | 0:723d48642d5c | 101 | } |
megrootens | 0:723d48642d5c | 102 | return (parity & kParity) == 0; |
megrootens | 0:723d48642d5c | 103 | } |
megrootens | 0:723d48642d5c | 104 | |
megrootens | 0:723d48642d5c | 105 | /** |
megrootens | 0:723d48642d5c | 106 | * Update the buffer with angular measurements |
megrootens | 0:723d48642d5c | 107 | * NOTE 1: |
megrootens | 0:723d48642d5c | 108 | * If the last command sent through Transfer was *not* AS_CMD_ANGLE |
megrootens | 0:723d48642d5c | 109 | * then we need an additional Transfer; this takes more time! |
megrootens | 0:723d48642d5c | 110 | * This should not occur, since Transfer is not *yet* used elsewhere. |
megrootens | 0:723d48642d5c | 111 | * NOTE 2: |
megrootens | 0:723d48642d5c | 112 | * We run a parity check on the results from the transfer. We only |
megrootens | 0:723d48642d5c | 113 | * update the angle_buffer_ with values that pass the parity check. |
megrootens | 0:723d48642d5c | 114 | * Measurement using Timer on K64F for last_command_ == AS_CMD_ANGLE |
megrootens | 0:723d48642d5c | 115 | * shows this function takes 87 or 88 us. |
megrootens | 0:723d48642d5c | 116 | */ |
megrootens | 2:111641f7e672 | 117 | void UpdateAngleBuffer() |
megrootens | 2:111641f7e672 | 118 | { |
megrootens | 0:723d48642d5c | 119 | // ensure that the new results indeed will be angles |
megrootens | 0:723d48642d5c | 120 | if (last_command_ != AS_CMD_ANGLE) { |
megrootens | 0:723d48642d5c | 121 | Transfer(AS_CMD_ANGLE); |
megrootens | 0:723d48642d5c | 122 | } |
megrootens | 0:723d48642d5c | 123 | |
megrootens | 0:723d48642d5c | 124 | // update the read buffer |
megrootens | 0:723d48642d5c | 125 | Transfer(AS_CMD_ANGLE); |
megrootens | 0:723d48642d5c | 126 | |
megrootens | 0:723d48642d5c | 127 | // update the angle buffer with parity checked values |
megrootens | 0:723d48642d5c | 128 | for (int i=0; i<kNumSensors_; ++i) { |
megrootens | 0:723d48642d5c | 129 | if (CheckParity(read_buffer_[i])) { |
megrootens | 0:723d48642d5c | 130 | // only update angles when parity is correct |
megrootens | 0:723d48642d5c | 131 | angle_buffer_[i] = read_buffer_[i]; |
megrootens | 0:723d48642d5c | 132 | } |
megrootens | 0:723d48642d5c | 133 | } |
megrootens | 0:723d48642d5c | 134 | } |
megrootens | 0:723d48642d5c | 135 | |
megrootens | 0:723d48642d5c | 136 | /** |
megrootens | 0:723d48642d5c | 137 | * @return: pointer to read_buffer_ |
megrootens | 0:723d48642d5c | 138 | */ |
megrootens | 0:723d48642d5c | 139 | const uint16_t* get_read_buffer() { return read_buffer_; } |
megrootens | 0:723d48642d5c | 140 | |
megrootens | 0:723d48642d5c | 141 | /** |
megrootens | 0:723d48642d5c | 142 | * @return: pointer to angle_buffer_ |
megrootens | 0:723d48642d5c | 143 | */ |
megrootens | 0:723d48642d5c | 144 | const uint16_t* get_angle_buffer() { return angle_buffer_; } |
megrootens | 0:723d48642d5c | 145 | |
megrootens | 0:723d48642d5c | 146 | /** |
megrootens | 0:723d48642d5c | 147 | * @return: pointer to angle_offet_ |
megrootens | 0:723d48642d5c | 148 | */ |
megrootens | 0:723d48642d5c | 149 | const uint16_t* get_angle_offset() { return angle_offset_; } |
megrootens | 0:723d48642d5c | 150 | |
megrootens | 0:723d48642d5c | 151 | /** |
megrootens | 1:94b48453d13a | 152 | * @return: pointer to directions_ |
megrootens | 1:94b48453d13a | 153 | */ |
megrootens | 1:94b48453d13a | 154 | const bool * get_directions_() { return directions_;} |
megrootens | 1:94b48453d13a | 155 | |
megrootens | 1:94b48453d13a | 156 | /** |
megrootens | 0:723d48642d5c | 157 | * You get the angles from two UpdateAngleBuffer() calls before |
megrootens | 0:723d48642d5c | 158 | * @return: 14 bits absolute position |
megrootens | 0:723d48642d5c | 159 | */ |
megrootens | 2:111641f7e672 | 160 | int getAngle(int i_sensor=0) |
megrootens | 2:111641f7e672 | 161 | { |
megrootens | 1:94b48453d13a | 162 | int ans = ((int) (angle_buffer_[i_sensor] & kMask)) - angle_offset_[i_sensor]; |
megrootens | 1:94b48453d13a | 163 | return directions_[i_sensor]?ans:-ans; |
megrootens | 0:723d48642d5c | 164 | } |
megrootens | 0:723d48642d5c | 165 | |
megrootens | 0:723d48642d5c | 166 | /** |
megrootens | 0:723d48642d5c | 167 | * You get the angles from two UpdateAngleBuffer() calls before |
megrootens | 0:723d48642d5c | 168 | * @return: revolution ratio in [0,1] |
megrootens | 0:723d48642d5c | 169 | */ |
megrootens | 0:723d48642d5c | 170 | float getAngleRatio(int i_sensor=0) { return (float) getAngle(i_sensor) / kCountsPerRev; } |
megrootens | 0:723d48642d5c | 171 | |
megrootens | 0:723d48642d5c | 172 | /** |
megrootens | 0:723d48642d5c | 173 | * You get the angles from two UpdateAngleBuffer() calls before |
megrootens | 0:723d48642d5c | 174 | * @return: angle in degrees |
megrootens | 0:723d48642d5c | 175 | */ |
megrootens | 0:723d48642d5c | 176 | float getAngleDegrees(int i_sensor=0) { return getAngleRatio(i_sensor) * kDegPerRev; } |
megrootens | 0:723d48642d5c | 177 | |
megrootens | 0:723d48642d5c | 178 | /** |
megrootens | 0:723d48642d5c | 179 | * You get the angles from two UpdateAngleBuffer() calls before |
megrootens | 0:723d48642d5c | 180 | * @return: angle in radians |
megrootens | 0:723d48642d5c | 181 | */ |
megrootens | 0:723d48642d5c | 182 | float getAngleRadians(int i_sensor=0) { return getAngleRatio(i_sensor) * kRadPerRev; } |
megrootens | 0:723d48642d5c | 183 | |
megrootens | 0:723d48642d5c | 184 | /** |
megrootens | 1:94b48453d13a | 185 | * Set direction for a sensor |
megrootens | 1:94b48453d13a | 186 | * @param i_sensor: id of sensor for which the offset is to be set |
megrootens | 1:94b48453d13a | 187 | * @param dir: true positive, false negative |
megrootens | 1:94b48453d13a | 188 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 1:94b48453d13a | 189 | */ |
megrootens | 2:111641f7e672 | 190 | bool setDirection(int i_sensor, bool dir) |
megrootens | 2:111641f7e672 | 191 | { |
megrootens | 1:94b48453d13a | 192 | if (i_sensor>-1 and i_sensor<kNumSensors_) { |
megrootens | 1:94b48453d13a | 193 | directions_[i_sensor] = dir; |
megrootens | 1:94b48453d13a | 194 | return true; |
megrootens | 1:94b48453d13a | 195 | } |
megrootens | 1:94b48453d13a | 196 | return false; |
megrootens | 1:94b48453d13a | 197 | } |
megrootens | 1:94b48453d13a | 198 | |
megrootens | 1:94b48453d13a | 199 | /** |
megrootens | 1:94b48453d13a | 200 | * Set direction for the first sensor |
megrootens | 1:94b48453d13a | 201 | * @param dir: true positive, false negative |
megrootens | 1:94b48453d13a | 202 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 1:94b48453d13a | 203 | */ |
megrootens | 2:111641f7e672 | 204 | bool setDirection(bool dir) |
megrootens | 2:111641f7e672 | 205 | { |
megrootens | 1:94b48453d13a | 206 | return setDirection(0,dir); |
megrootens | 1:94b48453d13a | 207 | } |
megrootens | 1:94b48453d13a | 208 | |
megrootens | 1:94b48453d13a | 209 | |
megrootens | 1:94b48453d13a | 210 | /** |
megrootens | 0:723d48642d5c | 211 | * Set offset for a sensor |
megrootens | 0:723d48642d5c | 212 | * @param i_sensor: id of sensor for which the offset is to be set |
megrootens | 0:723d48642d5c | 213 | * @param offset: offset in counts [0,2**14-1] |
megrootens | 0:723d48642d5c | 214 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 215 | */ |
megrootens | 2:111641f7e672 | 216 | bool setOffset(int i_sensor, uint16_t offset) |
megrootens | 2:111641f7e672 | 217 | { |
megrootens | 0:723d48642d5c | 218 | if (i_sensor>-1 and i_sensor<kNumSensors_) { |
megrootens | 0:723d48642d5c | 219 | angle_offset_[i_sensor] = offset; |
megrootens | 0:723d48642d5c | 220 | return true; |
megrootens | 0:723d48642d5c | 221 | } |
megrootens | 0:723d48642d5c | 222 | return false; |
megrootens | 0:723d48642d5c | 223 | } |
megrootens | 0:723d48642d5c | 224 | |
megrootens | 0:723d48642d5c | 225 | /** |
megrootens | 0:723d48642d5c | 226 | * Set offset for the first sensor |
megrootens | 0:723d48642d5c | 227 | * @param offset: offset in counts [0,2**14-1] |
megrootens | 0:723d48642d5c | 228 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 229 | */ |
megrootens | 0:723d48642d5c | 230 | bool setOffset(uint16_t offset) { return setOffset(0,offset); } |
megrootens | 0:723d48642d5c | 231 | |
megrootens | 0:723d48642d5c | 232 | /** |
megrootens | 0:723d48642d5c | 233 | * Set offset for a sensor |
megrootens | 0:723d48642d5c | 234 | * @param i_sensor: id of sensor for which the offset is to be set |
megrootens | 0:723d48642d5c | 235 | * @param offset_ratio: offset in ratio in [0,1] |
megrootens | 0:723d48642d5c | 236 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 237 | */ |
megrootens | 2:111641f7e672 | 238 | bool setOffsetRatio (int i_sensor, float offset_ratio) |
megrootens | 2:111641f7e672 | 239 | { |
megrootens | 0:723d48642d5c | 240 | return setOffset(i_sensor,offset_ratio*kCountsPerRev); |
megrootens | 0:723d48642d5c | 241 | } |
megrootens | 0:723d48642d5c | 242 | |
megrootens | 0:723d48642d5c | 243 | /** |
megrootens | 0:723d48642d5c | 244 | * Set offset for the first sensor |
megrootens | 0:723d48642d5c | 245 | * @param offset_ratio: offset in ratio in [0,1] |
megrootens | 0:723d48642d5c | 246 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 247 | */ |
megrootens | 2:111641f7e672 | 248 | bool setOffsetRatio(float offset_ratio) |
megrootens | 2:111641f7e672 | 249 | { |
megrootens | 0:723d48642d5c | 250 | return setOffsetRatio(0,offset_ratio); |
megrootens | 0:723d48642d5c | 251 | } |
megrootens | 0:723d48642d5c | 252 | |
megrootens | 0:723d48642d5c | 253 | /** |
megrootens | 0:723d48642d5c | 254 | * Set offset for a sensor |
megrootens | 0:723d48642d5c | 255 | * @param i_sensor: id of sensor for which the offset is to be set |
megrootens | 0:723d48642d5c | 256 | * @param offset_degrees: offset in degrees in [0,360] |
megrootens | 0:723d48642d5c | 257 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 258 | */ |
megrootens | 2:111641f7e672 | 259 | bool setOffsetDegrees(int i_sensor, float offset_degrees) |
megrootens | 2:111641f7e672 | 260 | { |
megrootens | 0:723d48642d5c | 261 | return setOffsetRatio(i_sensor,offset_degrees / kDegPerRev); |
megrootens | 0:723d48642d5c | 262 | } |
megrootens | 0:723d48642d5c | 263 | |
megrootens | 0:723d48642d5c | 264 | /** |
megrootens | 0:723d48642d5c | 265 | * Set offset for the first sensor |
megrootens | 0:723d48642d5c | 266 | * @param offset_degrees: offset in degrees in [0,360] |
megrootens | 0:723d48642d5c | 267 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 268 | */ |
megrootens | 2:111641f7e672 | 269 | bool setOffsetDegrees(float offset_degrees) |
megrootens | 2:111641f7e672 | 270 | { |
megrootens | 0:723d48642d5c | 271 | return setOffsetDegrees(0, offset_degrees); |
megrootens | 0:723d48642d5c | 272 | } |
megrootens | 0:723d48642d5c | 273 | |
megrootens | 0:723d48642d5c | 274 | /** |
megrootens | 0:723d48642d5c | 275 | * Set offset for a sensor |
megrootens | 0:723d48642d5c | 276 | * @param i_sensor: id of sensor for which the offset is to be set |
megrootens | 0:723d48642d5c | 277 | * @param offset_radians: offset in radians in [0,2*pi] |
megrootens | 0:723d48642d5c | 278 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 279 | */ |
megrootens | 2:111641f7e672 | 280 | bool setOffsetRadians(int i_sensor, float offset_radians) |
megrootens | 2:111641f7e672 | 281 | { |
megrootens | 0:723d48642d5c | 282 | return setOffsetRatio(i_sensor, offset_radians / kRadPerRev); |
megrootens | 0:723d48642d5c | 283 | } |
megrootens | 0:723d48642d5c | 284 | |
megrootens | 0:723d48642d5c | 285 | /** |
megrootens | 0:723d48642d5c | 286 | * Set offset for the first sensor |
megrootens | 0:723d48642d5c | 287 | * @param offset_radians: offset in radians in [0,2*pi] |
megrootens | 0:723d48642d5c | 288 | * @return: true if i_sensor in [0,kNumSensor_) |
megrootens | 0:723d48642d5c | 289 | */ |
megrootens | 2:111641f7e672 | 290 | bool setOffsetRadians(float offset_radians) |
megrootens | 2:111641f7e672 | 291 | { |
megrootens | 0:723d48642d5c | 292 | return setOffsetRadians(0, offset_radians); |
megrootens | 0:723d48642d5c | 293 | } |
megrootens | 1:94b48453d13a | 294 | |
megrootens | 1:94b48453d13a | 295 | |
megrootens | 0:723d48642d5c | 296 | |
megrootens | 0:723d48642d5c | 297 | |
megrootens | 0:723d48642d5c | 298 | protected: |
megrootens | 0:723d48642d5c | 299 | |
megrootens | 3:579e12eda4e6 | 300 | static const int kNumSensorBits = 14; // 14-bits sensor |
megrootens | 3:579e12eda4e6 | 301 | static const uint16_t kCountsPerRev = 0x4000; // 2**NUM_SENSOR_BITS |
megrootens | 3:579e12eda4e6 | 302 | static const uint16_t kMask = 0x3FFF; // 2**NUM_SENSOR_BITS - 1 |
megrootens | 3:579e12eda4e6 | 303 | static const int kParity = 1; // even parity |
megrootens | 3:579e12eda4e6 | 304 | |
megrootens | 3:579e12eda4e6 | 305 | static const int kSpiFrequency = 1000000; // AS5048 max 10 MHz |
megrootens | 3:579e12eda4e6 | 306 | static const int kSpiBitsPerTransfer = 8; |
megrootens | 3:579e12eda4e6 | 307 | static const int kSpiMode = 1; |
megrootens | 3:579e12eda4e6 | 308 | |
megrootens | 3:579e12eda4e6 | 309 | static const float kDegPerRev = 360.0f; // 360 degrees/rev |
megrootens | 3:579e12eda4e6 | 310 | static const float kRadPerRev = 6.28318530718f; // 2*pi rad/rev |
megrootens | 3:579e12eda4e6 | 311 | |
megrootens | 0:723d48642d5c | 312 | /** |
megrootens | 0:723d48642d5c | 313 | * Select (low) chip, and wait 1 us (at least 350 ns) |
megrootens | 0:723d48642d5c | 314 | */ |
megrootens | 0:723d48642d5c | 315 | void SelectChip() { chip_.write(0); wait_us(1); } |
megrootens | 0:723d48642d5c | 316 | |
megrootens | 0:723d48642d5c | 317 | /** |
megrootens | 0:723d48642d5c | 318 | * Deselect (high) chip, and wait 1 us (at least 350 ns) |
megrootens | 0:723d48642d5c | 319 | */ |
megrootens | 0:723d48642d5c | 320 | void DeselectChip() { chip_.write(1); wait_us(1); } |
megrootens | 0:723d48642d5c | 321 | |
megrootens | 0:723d48642d5c | 322 | /** |
megrootens | 0:723d48642d5c | 323 | * SPI transfer between each of the daisy chained sensors |
megrootens | 0:723d48642d5c | 324 | * @param cmd: Command to send |
megrootens | 0:723d48642d5c | 325 | */ |
megrootens | 2:111641f7e672 | 326 | void Transfer(As5048Command cmd) |
megrootens | 2:111641f7e672 | 327 | { |
megrootens | 0:723d48642d5c | 328 | SelectChip(); |
megrootens | 0:723d48642d5c | 329 | for(int i=0; i<kNumSensors_; ++i){ |
megrootens | 0:723d48642d5c | 330 | read_buffer_[i] = spi_.write(cmd>>8) << 8; |
megrootens | 0:723d48642d5c | 331 | read_buffer_[i] |= spi_.write(cmd & 0x00FF); |
megrootens | 0:723d48642d5c | 332 | } |
megrootens | 0:723d48642d5c | 333 | DeselectChip(); |
megrootens | 0:723d48642d5c | 334 | last_command_ = cmd; |
megrootens | 0:723d48642d5c | 335 | } |
megrootens | 0:723d48642d5c | 336 | |
megrootens | 0:723d48642d5c | 337 | const int kNumSensors_; // number of sensors in daisy chain |
megrootens | 0:723d48642d5c | 338 | DigitalOut chip_; // chip select port |
megrootens | 0:723d48642d5c | 339 | SPI spi_; // mbed spi communiation object |
megrootens | 0:723d48642d5c | 340 | |
megrootens | 0:723d48642d5c | 341 | uint16_t* read_buffer_; // buffer for results from last transfer |
megrootens | 0:723d48642d5c | 342 | uint16_t* angle_buffer_; // buffer for angle results from last transfer |
megrootens | 0:723d48642d5c | 343 | uint16_t* angle_offset_; // offset array for each sensor |
megrootens | 1:94b48453d13a | 344 | bool* directions_; // direction true positive, false negative |
megrootens | 0:723d48642d5c | 345 | |
megrootens | 0:723d48642d5c | 346 | As5048Command last_command_;// command sent during last Transfer |
megrootens | 0:723d48642d5c | 347 | |
megrootens | 0:723d48642d5c | 348 | }; |
megrootens | 0:723d48642d5c | 349 | #endif |