BMA423Driver < IoT_Course

---+ The driver for BMA423 Triaxial Acceleration Sensor

The !MicroPython layer in bma423 from [[https://github.com/OPHoperHPO/lilygo-ttgo-twatch-2020-micropython][https://github.com/OPHoperHPO/lilygo-ttgo-twatch-2020-micropython ]] was not working because it uses deprecated calls to !I2C in !MicroPython.

However, I found that Daniel Thomson has also written a !MicroPython interface to the [[https://github.com/BoschSensortec/BMA423-Sensor-API][BMA423 API from Bosch SensorTec]], which was easier to adapt to the t-watch.

https://github.com/daniel-thompson/bma42x-upy

I had to make only a few modifications: Daniel uses a BMA421 while the t-watch uses a BMA423. I therefore had to replace all occurrences of "<i>bma421"</i> in bma42x.c by "<i>bma423". </i>In addition the t-watch uses the secondary !I2C address 0x19 for the chip (the primary address is 0x18) and I therefore had to replace ic2_addr in the device descriptor to BMA4_I2C_ADDR_SECONDARY.

Daniel also supplies a few example programs, which are essentially ports of the Bosch examples ported from C to !MicroPython

The !BMA42X driver provides the following methods:
   * !BMA42X(i2c): create a !BMA42X object. The i2c parameter must be a initialized !SoftI2C object
   * debug(on_off): switch debugging on / off
   * feature_enable(feature,on_off): feature: the feature to be enabled or disabled, on_off to switch the feature on or off. The features are listed below.
   * get_offset_comp(): Gets the status of the accel offset compensation
   * get_temperature(unit): gets the temperature in the requested units. Possible units: see below
   * init (called when the object is created)
   * map_interrupt(int_line, interrupt_types): Map the interrupt to either pin1 or pin2
   * read_accel_xyz(): read the accel data for x,y,z from the sensor. The data are returned as a tuple (x,y,z)
   * read_int_status(): reads the hardware interrupt status from the sensor
   * set accel_config(accel_config): set the acceleration sensor config. See the accelerometer.py example in order to understand how to do this.
   * reset_step_counter(): reset the step counter
   * set accel_enable(on_off): enables or disables the accel in the sensor
   * set_any_mot_config(any_mot_config): set the configuration for any motion interrupts. See example motion_interrupt.py in order to understand how to do this.
   * set_no_mot_config(no_mot_config): set the configuration for no motion interrupts. See example motion_interrupt.py in order to understand how to do this.
   * set_command_reg(value): set the command register
      * 0xb6: triggers a soft reset
      * 0xb0: clears all data in the !FiFo
      * 0xf0: resets the acceleration data path
   * set_offset_comp(on_off): enables the offset compensation for filtered and unfiltered accel data
   * step_detector_enable(on_off): enables or disables the step detector feature in the sensor
   * step_counter_output(): gets the number of counted steps of the step counter feature from the sensor
   * step_counter_set_watermark(value): sets the watermark level for step counter interrupt in the sensor
   * write_config_file(): write the binary configuration data to the sensor
The driver also defines the following constants:

The registers:
   * ACCEL_CONFIG_ADDR
   * POWER_CONF_ADDR
   * POWER_CTRL_ADDR
   * NV_CONFIG_ADDR
Configuration values:
   * ACCEL_RANGE_2G
   * ACCEL_RANGE_4G
   * ACCEL_RANGE_8G
   * ACCEL_RANGE_16G
   * ACCEL_NORMAL_AVG4
   * (OUTPUT_DATA_RATE_50HZ
   * OUTPUT_DATA_RATE_100HZ
   * CIC_AVG_MODE
   * CONTINUOUS_MODE
Temperature parameters:
   * SCALE_TEMP
   * DEG
   * FAHREN
   * KELVIN
Features
   * STEP_CNTR
   * STEP_ACT
   * WRIST_WEAR
   * SINGLE_TAP
   * DOUBLE_TAP

Interrupts
   * INTR1_MAP
   * INTR2_MAP
   * STEP_CNTR_INT
   * ANY_MOT_INT
   * NO_MOT_INT
Enable axis
   * DIS_ALL_AXIS
   * X_AXIS_EN
   * Y_AXIS_EN
   * Z_AXIS_EN
   * EN_ALL_AXIS

-- %USERSIG{UliRaich - 2021-01-27}%

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This topic: IoT_Course_English > WebHome > TheT-watch2020Hardware > BMA423Driver
Topic revision: r4 - 2021-01-28 - UliRaich