openpilot is an open source driver assistance system. openpilot performs the functions of Automated Lane Centering and Adaptive Cruise Control for over 200 supported car makes and models.
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#include "bmx055_accel.h"
#include <cassert>
#include "common/swaglog.h"
#include "common/timing.h"
#include "common/util.h"
BMX055_Accel::BMX055_Accel(I2CBus *bus) : I2CSensor(bus) {}
int BMX055_Accel::init() {
int ret = verify_chip_id(BMX055_ACCEL_I2C_REG_ID, {BMX055_ACCEL_CHIP_ID});
if (ret == -1) return -1;
ret = set_register(BMX055_ACCEL_I2C_REG_PMU, BMX055_ACCEL_NORMAL_MODE);
if (ret < 0) {
goto fail;
}
// bmx055 accel has a 1.3ms wakeup time from deep suspend mode
util::sleep_for(10);
// High bandwidth
// ret = set_register(BMX055_ACCEL_I2C_REG_HBW, BMX055_ACCEL_HBW_ENABLE);
// if (ret < 0) {
// goto fail;
// }
// Low bandwidth
ret = set_register(BMX055_ACCEL_I2C_REG_HBW, BMX055_ACCEL_HBW_DISABLE);
if (ret < 0) {
goto fail;
}
ret = set_register(BMX055_ACCEL_I2C_REG_BW, BMX055_ACCEL_BW_125HZ);
if (ret < 0) {
goto fail;
}
fail:
return ret;
}
int BMX055_Accel::shutdown() {
// enter deep suspend mode (lowest power mode)
int ret = set_register(BMX055_ACCEL_I2C_REG_PMU, BMX055_ACCEL_DEEP_SUSPEND);
if (ret < 0) {
LOGE("Could not move BMX055 ACCEL in deep suspend mode!")
}
return ret;
}
bool BMX055_Accel::get_event(MessageBuilder &msg, uint64_t ts) {
uint64_t start_time = nanos_since_boot();
uint8_t buffer[6];
int len = read_register(BMX055_ACCEL_I2C_REG_X_LSB, buffer, sizeof(buffer));
assert(len == 6);
// 12 bit = +-2g
float scale = 9.81 * 2.0f / (1 << 11);
float x = -read_12_bit(buffer[0], buffer[1]) * scale;
float y = -read_12_bit(buffer[2], buffer[3]) * scale;
float z = read_12_bit(buffer[4], buffer[5]) * scale;
auto event = msg.initEvent().initAccelerometer2();
event.setSource(cereal::SensorEventData::SensorSource::BMX055);
event.setVersion(1);
event.setSensor(SENSOR_ACCELEROMETER);
event.setType(SENSOR_TYPE_ACCELEROMETER);
event.setTimestamp(start_time);
float xyz[] = {x, y, z};
auto svec = event.initAcceleration();
svec.setV(xyz);
svec.setStatus(true);
return true;
}