Accel 3 Click

How does it work?

Accel 3 Click is based on the H3LIS331DL, a low-power, high-g 3-axis digital accelerometer from STMicroelectronics. The proprietary process technology allows the processing of suspended silicon structures, which are attached to the substrate in a few points called anchors, free to move in the direction of the sensed acceleration. When acceleration is applied to the sensor, the proof mass displaces from its nominal position, causing an imbalance in the capacitive half bridge. This imbalance is measured using charge integration in response to a voltage pulse applied to the capacitor. The sensors interface is factory calibrated for sensitivity and zero-g level. The trim values are stored inside the device in non-volatile memory. Any time the device is turned on, the trim parameters are downloaded into the registers to be used during active operation, allowing the device to be used without further calibration.

The acceleration data of Accel 3 Click is accessed through I2C or SPI interface, with a 400KHz fast mode frequency for I2C, and a 10MHz clock frequency for SPI communication. The selection is made by positioning four SMD jumpers labeled SPI I2C in an appropriate position, with the I2C set by default. Note that all the jumpers’ positions must be on the same side, or the Click board™ may become unresponsive. While the I2C interface is selected, the H3LIS331DL allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled I2C ADDR (0 set by default).

The H3LIS331DL also possesses two inertial interrupts, both accessible over the INT2 INT1 jumper and INT pin of the mikroBUS™ socket. The user can completely program the functions, threshold, and timing of the two interrupt signals through the selected interface. They signal the host MCU that a motion event has been sensed.

This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Specifications

Pinout diagram

This table shows how the pinout on Accel 3 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
	NC	2	RST	INT	15	INT	Interrupt
SPI Chip Select	CS	3	CS	RX	14	NC
SPI Clock	SCK	4	SCK	TX	13	NC
SPI Data OUT	SDO	5	MISO	SCL	12	SCL	I2C Clock
SPI Data IN	SDI	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Accel 3 Click electrical specifications

Software Support

We provide a library for the Accel 3 Click as well as a demo application (example), developed using MIKROE compilers. The demo can run on all the main MIKROE development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for Accel3 Click driver.

Key functions

• This function select communication mode and executes start initialization.

• This function reads Accel data ( X, Y and Z axis ) from the desired Accel registers of the H3LIS331DL module.

Example Description

This is an example which demonstrates the usage of Accel 3 Click board™.

 void application_task ( void ) 
 { 
     accel3_read_data( &accel3, &accel3_data ); 
     Delay_ms ( 100 ); 

     log_printf( &logger, "        Accelerometer       rn" ); 
     log_printf( &logger, "----------------------------rn" ); 
     log_printf( &logger, "        X = %6d rn", accel3_data.x ); 
     log_printf( &logger, "        Y = %6d rn", accel3_data.y ); 
     log_printf( &logger, "        Z = %6d rn", accel3_data.z ); 
     log_printf( &logger, "----------------------------rn" ); 

     Delay_ms ( 1000 ); 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Accel3

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MIKROE Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.