Crate bma400

Crate bma400 

Source
Expand description

A platform-agnostic driver for the BMA400 accelerometer implemented using embedded-hal traits.

§Basic Usage

I²C - cargo add bma400 --features=i2c

// Import an embedded hal implementation
use embedded_hal_mock::eh1::i2c::{Mock, Transaction};
// replace as appropriate w/ hal crate for your MCU
use bma400::{
    BMA400,
    PowerMode,
    Scale,
};
// i2c implements embedded-hal i2c::I2c
let mut accelerometer = BMA400::new_i2c(&mut i2c).unwrap();

SPI - cargo add bma400 --features=spi

// Import an embedded hal implementation
use embedded_hal_mock::eh1::spi::{Mock, Transaction};
// replace as appropriate w/ hal crate for your MCU
use bma400::{
    BMA400,
    PowerMode,
    Scale,
};
// spi implements embedded-hal spi::SpiDevice
let mut accelerometer = BMA400::new_spi(&mut spi).unwrap();

From here it’s the same API for both:

// The accelerometer is in sleep mode at power on
// Let's wake it up and set the scale to 2g
accelerometer
    .config_accel()
    .with_power_mode(PowerMode::Normal)
    .with_scale(Scale::Range2G)
    .write().unwrap();
// Read a single measurment
if let Ok(measurement) = accelerometer.get_data() {
    assert_eq!(30, measurement.x);
    assert_eq!(16, measurement.y);
    assert_eq!(988, measurement.z);
}

§Features

BMA400 can currently be compiled with the following feature flags:

  • i2c: Use I²C
  • spi: Use SPI
  • float: Enable functions returning floating point values. Currently just get_temp_celsius()
  • embedded-hal-async: Swaps blocking API for async API implemented using embedded-hal-async traits

§The Bosch BMA400 Accelerometer

Datasheet

Basic Description 12 bit, digital, triaxial acceleration sensor with smart on-chip motion and position-triggered interrupt features.

Key features

  • Small Package Size
    • LGA package (12 pins), footprint 2mm x 2mm, height 0.95 mm
  • Ultra-low power
    • Low current consumption of data acquisition without compromising on performance (< 14.5 µA with highest performance)
  • Programmable functionality
    • Acceleration ranges ±2g/±4g/±8g/±16g
    • Low-pass filter bandwidths = (0.24/0.48)*ODR up to a max. output data read out of 800Hz
  • On-chip FIFO
    • Integrated FIFO on sensor with 1 KB
  • On-chip interrupt features
    • Auto-low power/Auto wakeup
    • Activity/In-activity
    • Step Counter (overall device current consumption 4µA)
    • Activity Recognition (Walking, Running, Standing still)
    • Orientation detection
    • Tap/double tap
  • Digital interface
    • SPI (4-wire, 3-wire)
    • I²C
    • 2 interrupt pins
    • VDDIO voltage range: 1.2V to 3.6V
  • RoHS compliant, halogen-free

Typical applications

  • Step Counting with ultra-low current consumption for extensive battery lifetime
  • Advanced system power management for mobile applications and (smart) watches
  • Fitness applications / Activity Tracking
  • Tap / double tap sensing
  • Drop detection for warranty logging
  • Window/door measurements for climate control and alarm systems
  • IoT applications powered by coin cell driven batteries, requiring <1µA and auto-wakeup functionality

  1. For more info on I²C address select, see: https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bma400-ds000.pdf#page=108 ↩

Re-exports§

pub use types::*;

Modules§

config
Accelerometer configuration options
types
The structs and enums making up the driver API

Structs§

BMA400
A BMA400 device
I2CInterface
I²C Interface wrapper
SPIInterface
SPI Interface wrapper