bma400-rs

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

Status

• Support Basic Sensor Features
• SPI Support
• Support Programmable (Custom) Interrupts
• Tests
• Documentation
• More Examples

Basic Usage

I²C - cargo add bma400 --features=i2c-default

// Import an embedded hal implementation
use linux_embedded_hal::I2cdev; // replace as appropriate w/ hal crate for your MCU
use bma400::{
    BMA400,
    PowerMode,
    Scale,
};
// i2c implements embedded-hal i2c::WriteRead and i2c::Write
let mut accelerometer = BMA400::new_i2c(i2c).unwrap();

SPI - cargo add bma400 --features=spi

// Import an embedded hal implementation
use linux_embedded_hal::{
 Spidev, 
 Pin
}; // replace as appropriate w/ hal crate for your MCU
use bma400::{
    BMA400,
    PowerMode,
    Scale,
};
// spi implements embedded-hal spi::Transfer and spi::Write
// csb_pin implements embedded-hal digital::v2::OutputPin
let mut accelerometer = BMA400::new_spi(spi, csb_pin).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);
}

For a full example using the tap interrupt mapped to a GPIO pin on the nrf52833, see examples/.

About the Sensor

(from the manufacturer)

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

License

Licensed under your choice of either:

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be licensed as above, without any additional terms or conditions.