diff options
Diffstat (limited to 'watch-library/driver/lis2dh.c')
| -rw-r--r-- | watch-library/driver/lis2dh.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/watch-library/driver/lis2dh.c b/watch-library/driver/lis2dh.c new file mode 100644 index 00000000..24534481 --- /dev/null +++ b/watch-library/driver/lis2dh.c @@ -0,0 +1,116 @@ +/* + * MIT License + * + * Copyright (c) 2021 Joey Castillo + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in all + * copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include "lis2dh.h" +#include "watch.h" + +bool lis2dh_begin() { + if (lis2dh_get_device_id() != LIS2DH_WHO_AM_I_VAL) { + return false; + } + // Enable all axes, start at lowest possible data rate + watch_i2c_write8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL1, LIS2DH_CTRL1_VAL_XEN | + LIS2DH_CTRL1_VAL_YEN | + LIS2DH_CTRL1_VAL_ZEN | + LIS2DH_CTRL1_VAL_ODR_1HZ); + // Enable block data update (output registers not updated until MSB and LSB have been read) + watch_i2c_write8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL4, LIS2DH_CTRL4_VAL_BDU); + + return true; +} + +uint8_t lis2dh_get_device_id() { + return watch_i2c_read8(LIS2DH_ADDRESS, LIS2DH_REG_WHO_AM_I); +} + +bool lis2dh_have_new_data() { + uint8_t retval = watch_i2c_read8(LIS2DH_ADDRESS, LIS2DH_REG_STATUS); + return !!retval; // return true if any bit is set +} + +lis2dh_reading lis2dh_get_raw_reading() { + uint8_t buffer[6]; + uint8_t reg = LIS2DH_REG_OUT_X_L | 0x80; // set high bit for consecutive reads + lis2dh_reading retval; + + watch_i2c_send(LIS2DH_ADDRESS, ®, 1); + watch_i2c_receive(LIS2DH_ADDRESS, (uint8_t *)&buffer, 6); + + retval.x = buffer[0]; + retval.x |= ((uint16_t)buffer[1]) << 8; + retval.y = buffer[2]; + retval.y |= ((uint16_t)buffer[3]) << 8; + retval.z = buffer[4]; + retval.z |= ((uint16_t)buffer[5]) << 8; + + return retval; +} + + lis2dh_acceleration_measurement lis2dh_get_acceleration_measurement(lis2dh_reading *out_reading) { + lis2dh_reading reading = lis2dh_get_raw_reading(); + uint8_t range = lis2dh_get_range(); + if (out_reading != NULL) *out_reading = reading; + + // this bit is cribbed from Adafruit's LIS3DH driver; from their notes, the magic number below + // converts from 16-bit lsb to 10-bit and divides by 1k to convert from milli-gs. + // final value is raw_lsb => 10-bit lsb -> milli-gs -> gs + uint8_t lsb_value = 1; + if (range == LIS2DH_RANGE_2_G) lsb_value = 4; + if (range == LIS2DH_RANGE_4_G) lsb_value = 8; + if (range == LIS2DH_RANGE_8_G) lsb_value = 16; + if (range == LIS2DH_RANGE_16_G) lsb_value = 48; + + lis2dh_acceleration_measurement retval; + + retval.x = lsb_value * ((float)reading.x / 64000.0); + retval.y = lsb_value * ((float)reading.y / 64000.0); + retval.z = lsb_value * ((float)reading.z / 64000.0); + + return retval; +} + +void lis2dh_set_range(lis2dh_range_t range) { + uint8_t val = watch_i2c_read8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL4) & 0xCF; + uint8_t bits = range << 4; + + watch_i2c_write8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL4, val | bits); +} + +lis2dh_range_t lis2dh_get_range() { + uint8_t retval = watch_i2c_read8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL4) & 0x30; + retval >>= 4; + return (lis2dh_range_t)retval; +} + + +void lis2dh_set_data_rate(lis2dh_data_rate_t dataRate) { + uint8_t val = watch_i2c_read8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL1) & 0x0F; + uint8_t bits = dataRate << 4; + + watch_i2c_write8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL1, val | bits); +} + +lis2dh_data_rate_t lis2dh_get_data_rate() { + return watch_i2c_read8(LIS2DH_ADDRESS, LIS2DH_REG_CTRL1) >> 4; +} |