Matthias Grob / Mbed 2 deprecated FlyBed2

My fully self designed first stable working Quadrocopter Software.

Dependencies:   mbed

Dependents:   fluy343

/media/uploads/maetugr/dsc09031.jpg

IMU/Sensors/MPU9250/MPU9250.cpp@10:14390c90c3f5, 2015-08-31 (annotated)

Committer:
maetugr
Date:
Mon Aug 31 20:20:50 2015 +0000
Revision:
10:14390c90c3f5
before changing to MPU9250

Who changed what in which revision?

UserRevisionLine numberNew contents of line
maetugr 10:14390c90c3f5 1 #include "MPU9250.h"
maetugr 10:14390c90c3f5 2
maetugr 10:14390c90c3f5 3 MPU9250::MPU9250(PinName MOSI, PinName MISO, PinName SCLK, PinName CS) : spi(MOSI, MISO, SCLK), cs(CS) {
maetugr 10:14390c90c3f5 4 deselect(); // chip must be deselected first
maetugr 10:14390c90c3f5 5 spi.format(8,0); // setup the spi for standard 8 bit data and SPI-Mode 0
maetugr 10:14390c90c3f5 6 spi.frequency(5e6); // with a 5MHz clock rate
maetugr 10:14390c90c3f5 7
maetugr 10:14390c90c3f5 8 /*
maetugr 10:14390c90c3f5 9 last 3 Bits of|Accelerometer(Fs=1kHz) |Gyroscope
maetugr 10:14390c90c3f5 10 MPU9250_CONFIG|Bandwidth(Hz)|Delay(ms)|Bandwidth(Hz)|Delay(ms)|Fs(kHz)
maetugr 10:14390c90c3f5 11 -------------------------------------------------------------------------
maetugr 10:14390c90c3f5 12 0 |260 |0 |256 |0.98 |8
maetugr 10:14390c90c3f5 13 1 |184 |2.0 |188 |1.9 |1
maetugr 10:14390c90c3f5 14 2 |94 |3.0 |98 |2.8 |1
maetugr 10:14390c90c3f5 15 3 |44 |4.9 |42 |4.8 |1
maetugr 10:14390c90c3f5 16 4 |21 |8.5 |20 |8.3 |1
maetugr 10:14390c90c3f5 17 5 |10 |13.8 |10 |13.4 |1
maetugr 10:14390c90c3f5 18 6 |5 |19.0 |5 |18.6 |1
maetugr 10:14390c90c3f5 19 */
maetugr 10:14390c90c3f5 20 writeRegister8(MPU9250_CONFIG, 0x06);
maetugr 10:14390c90c3f5 21 writeRegister8(MPU9250_GYRO_CONFIG, 0x18); // scales gyros range to +-2000dps
maetugr 10:14390c90c3f5 22 writeRegister8(MPU9250_ACCEL_CONFIG, 0x08); // scales accelerometers range to +-4g
maetugr 10:14390c90c3f5 23 }
maetugr 10:14390c90c3f5 24
maetugr 10:14390c90c3f5 25 uint8_t MPU9250::getWhoami() {
maetugr 10:14390c90c3f5 26 return readRegister8(MPU9250_WHO_AM_I);
maetugr 10:14390c90c3f5 27 }
maetugr 10:14390c90c3f5 28
maetugr 10:14390c90c3f5 29 float MPU9250::getTemperature() {
maetugr 10:14390c90c3f5 30 int16_t data = readRegister16(MPU9250_TEMP_OUT_H);
maetugr 10:14390c90c3f5 31 return ((data - 21) / 333.87) + 21; // formula from register map p.33
maetugr 10:14390c90c3f5 32 }
maetugr 10:14390c90c3f5 33
maetugr 10:14390c90c3f5 34 void MPU9250::readGyro() {
maetugr 10:14390c90c3f5 35 int16_t rawGyro[3];
maetugr 10:14390c90c3f5 36 readRegister48(MPU9250_GYRO_XOUT_H, rawGyro);
maetugr 10:14390c90c3f5 37
maetugr 10:14390c90c3f5 38 int16_t offsetGyro[3] = {-31, -15, -11}; // TODO: make better calibration
maetugr 10:14390c90c3f5 39
maetugr 10:14390c90c3f5 40 for (int i = 0; i < 3; i++)
maetugr 10:14390c90c3f5 41 Gyro[i] = (rawGyro[i] - offsetGyro[i])*0.07; // subtract offset from calibration and multiply unit factor to get degree per second (datasheet p.10)
maetugr 10:14390c90c3f5 42 }
maetugr 10:14390c90c3f5 43
maetugr 10:14390c90c3f5 44 void MPU9250::readAcc() {
maetugr 10:14390c90c3f5 45 int16_t rawAcc[3];
maetugr 10:14390c90c3f5 46 readRegister48(MPU9250_ACCEL_XOUT_H, rawAcc);
maetugr 10:14390c90c3f5 47
maetugr 10:14390c90c3f5 48 int16_t offsetAcc[3] = {-120, -48, -438}; // TODO: make better calibration
maetugr 10:14390c90c3f5 49
maetugr 10:14390c90c3f5 50 for (int i = 0; i < 3; i++)
maetugr 10:14390c90c3f5 51 Acc[i] = (rawAcc[i] - offsetAcc[i])/8192.0; // TODO: didn't care about units because IMU-algorithm just uses vector direction
maetugr 10:14390c90c3f5 52 }
maetugr 10:14390c90c3f5 53
maetugr 10:14390c90c3f5 54 // PRIVATE Methods ------------------------------------------------------------------------------------
maetugr 10:14390c90c3f5 55
maetugr 10:14390c90c3f5 56
maetugr 10:14390c90c3f5 57 // SPI Interface --------------------------------------------------------------------------------------
maetugr 10:14390c90c3f5 58 uint8_t MPU9250::readRegister8(uint8_t reg) {
maetugr 10:14390c90c3f5 59 uint8_t result;
maetugr 10:14390c90c3f5 60 readRegister(reg, &result, 1);
maetugr 10:14390c90c3f5 61 return result;
maetugr 10:14390c90c3f5 62 }
maetugr 10:14390c90c3f5 63
maetugr 10:14390c90c3f5 64 uint16_t MPU9250::readRegister16(uint8_t reg) {
maetugr 10:14390c90c3f5 65 uint8_t result[2];
maetugr 10:14390c90c3f5 66 readRegister(reg, result, 2);
maetugr 10:14390c90c3f5 67 return result[0]<<8 | result[1]; // join 8-Bit pieces to 16-bit short integer
maetugr 10:14390c90c3f5 68 }
maetugr 10:14390c90c3f5 69
maetugr 10:14390c90c3f5 70 void MPU9250::readRegister48(uint8_t reg, int16_t *buffer) {
maetugr 10:14390c90c3f5 71 uint8_t result[6];
maetugr 10:14390c90c3f5 72 readRegister(reg, result, 6);
maetugr 10:14390c90c3f5 73 buffer[0] = (int16_t) (result[0] << 8 | result[1]); // join 8-Bit pieces to 16-bit short integers
maetugr 10:14390c90c3f5 74 buffer[1] = (int16_t) (result[2] << 8 | result[3]);
maetugr 10:14390c90c3f5 75 buffer[2] = (int16_t) (result[4] << 8 | result[5]);
maetugr 10:14390c90c3f5 76 }
maetugr 10:14390c90c3f5 77
maetugr 10:14390c90c3f5 78 void MPU9250::writeRegister8(uint8_t reg, uint8_t buffer) {
maetugr 10:14390c90c3f5 79 writeRegister(reg, &buffer, 1);
maetugr 10:14390c90c3f5 80 }
maetugr 10:14390c90c3f5 81
maetugr 10:14390c90c3f5 82 void MPU9250::readRegister(uint8_t reg, uint8_t *buffer, int length) {
maetugr 10:14390c90c3f5 83 select();
maetugr 10:14390c90c3f5 84 spi.write(reg | 0x80); // send the register address we want to read and the read flag
maetugr 10:14390c90c3f5 85 for(int i=0; i<length; i++) // get data
maetugr 10:14390c90c3f5 86 buffer[i] = spi.write(0x00);
maetugr 10:14390c90c3f5 87 deselect();
maetugr 10:14390c90c3f5 88 }
maetugr 10:14390c90c3f5 89
maetugr 10:14390c90c3f5 90 void MPU9250::writeRegister(uint8_t reg, uint8_t *buffer, int length) {
maetugr 10:14390c90c3f5 91 select();
maetugr 10:14390c90c3f5 92 spi.write(reg & ~0x80); // send the register address we want to write and the write flag
maetugr 10:14390c90c3f5 93 for(int i=0; i<length; i++) // put data
maetugr 10:14390c90c3f5 94 spi.write(buffer[i]);
maetugr 10:14390c90c3f5 95 deselect();
maetugr 10:14390c90c3f5 96 }
maetugr 10:14390c90c3f5 97
maetugr 10:14390c90c3f5 98 void MPU9250::select() { cs = 0; } // set Cable Select pin low to start SPI transaction
maetugr 10:14390c90c3f5 99 void MPU9250::deselect() { cs = 1; } // set Cable Select pin high to stop SPI transaction