Compass Click

How does it work?

Compass Click is based on the LSM303DLHC, an ultra-compact, high-performance e-compass module featuring a 3D digital linear acceleration sensor and a 3D digital magnetic sensor from STMicroelectronics. The LSM303DLHC is manufactured using specialized micromachining processes and includes specific sensing elements capable of measuring both the linear acceleration and magnetic field, thus providing a 16-bit data signal to the host MCU through an I2C serial interface. It has linear acceleration full-scales of ±2g/±4g/±8g/±16g and a magnetic field full-scale of ±1.3/±1.9/±2.5/±4.0/±4.7/±5.6/±8.1 gauss, fully selectable by the user.

The LSM303DLHC provides two different acceleration operating modes, respectively reported as “Normal mode” and “Low-power mod”. While normal mode guarantees high resolution, low-power mode further reduces the current consumption. Besides, magnetic and accelerometer parts can be enabled or put into Power-Down mode separately.

Compass Click communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings with a maximum clock frequency of 400kHz. It also features a data-ready signal, routed to the RST pin on the mikroBUS™ socket, which indicates when a new set of measured acceleration and magnetic data are available, simplifying data synchronization in the digital system that uses the device. The LSM303DLHC may also be configured to generate a free-fall interrupt signal according to a programmed acceleration event along the enabled axes.

This Click board™ can be operated only 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 Compass 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
Data Ready	RDY	2	RST	INT	15	INT	Interrupt
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	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

Compass Click electrical specifications

Software Support

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

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

Library Description

This library contains API for Compass Click driver.

Key functions

• This function reads data for megnetic axes.

• This function reads data for accelerometer axes.

• This function writes magnet data to the desired register.

Example Description

This application measures magnetic and accelerometer axes data and shows them over USBUART

void application_task ( void ) 
 { 
     int16_t accel_axis[ 3 ]; 
     int16_t magnet_axis[ 3 ]; 

     compass_read_magnet_axis( &compass, &magnet_axis[ 0 ], &magnet_axis[ 1 ], &magnet_axis[ 2 ] ); 
     log_printf( &logger, "Magnet axis -- X: %d Y: %d  Z: %d rn", magnet_axis[ 0 ], magnet_axis[ 1 ], magnet_axis[ 2 ] ); 

     compass_read_accel_axis ( &compass, &accel_axis[ 0 ], &accel_axis[ 1 ], &accel_axis[ 2 ] ); 
     log_printf( &logger, "Magnet axis -- X: %d Y: %d  Z: %d rn", accel_axis[ 0 ], accel_axis[ 1 ], accel_axis[ 2 ] ); 

     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 way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Compass

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 MikroElektronika compilers.

mikroSDK

This Click board™ is supported with mikroSDK - MikroElektronika 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.