ADXL355 DIGITAL ACCELEROMETER¶
Introduction¶
Acceleration measurement is a common requirement in many embedded systems. The ADXL355 is a high-precision, low-power, three-axis digital accelerometer suitable for various applications such as motion detection, tilt measurement, and vibration monitoring.
The ADXL355 features low noise density, high resolution, and a wide measurement range, making it ideal for applications requiring accurate and reliable acceleration data.
Key Features (Summary)¶
- Low Noise: Typical noise density of approximately 22.5 µg/√Hz (all axes)
- Low Temperature Drift: 0 g offset variation with temperature ≤ 0.15 mg/°C (all axes)
- Low Power Consumption: Measurement mode approximately 200 µA; standby approximately 21 µA
- Selectable Measurement Ranges: ±2 g, ±4 g, ±8 g (model/configuration dependent)
- Interface: SPI and I2C (digital output)
- High Resolution: Built-in 20-bit ADC, supports synchronous sampling and data interpolation
- Programmable Digital Filtering: Supports high/low-pass digital filtering
- Integrated Temperature Sensor and Self-Test Functionality
- Supply Voltage: 2.25 V to 3.6 V (with internal regulator enabled); typically 1.8 V ±10% when bypassing internal LDO
- Operating Temperature: -40°C to +125°C
- Package: 14-lead LCC, approximately 6.0 × 5.6 × 2.2 mm
Typical Applications¶
- Inertial Measurement Units (IMU), Attitude and Heading Reference Systems (AHRS)
- Platform Stabilization and Motion Compensation
- Structural Health Monitoring and Vibration Analysis
- Seismic/Shock Detection and Imaging
- Tilt Sensing, Robotics, IoT Sensor Nodes, and Condition Monitoring
Technical Specifications (Summary Table)¶
| Parameter | Specification / Description |
|---|---|
| Measurement Range | ±2 g, ±4 g, ±8 g (selectable) |
| Resolution | 20 bit (ADXL355) |
| Noise Density | Approximately 22.5 µg/√Hz (typical) |
| Interface | SPI, I2C (ADXL355) |
| Operating Voltage | 2.25 V to 3.6 V (with internal regulator) |
| Operating Temperature | -40°C to +125°C |
DMA Support Note¶
DMA Configuration
In this implementation, the ADXL355 driver uses the SPI3 bus for communication, which has DMA enabled (SPI_DMA_CH_AUTO). Enabling DMA provides the following benefits:
- Reduced CPU Usage: SPI data transfers are automatically handled by the DMA controller, freeing the CPU from data transfer operations
- Improved Transfer Performance: Especially beneficial for ADXL355's high-frequency sampling scenarios (up to 4000 Hz output data rate)
- Automatic Usage: Once DMA is enabled during SPI bus initialization, all SPI transactions (including
spi_device_polling_transmit()) automatically use DMA without additional configuration
The initialization process will output log messages confirming that DMA is enabled, and all SPI read/write operations will automatically utilize DMA for data transfer.