Accel 22 Click Board™

How Does The Accel 22 Click Board™ Work?

The Accel 22 Click Board™ as its foundation uses the ADXL367, a complete 3-axis acceleration measurement system that operates at low power consumption levels, consisting as well of an ADC for synchronous conversion of input from a third sensor and a temperature sensor from Analog Devices. It measures both dynamic accelerations, resulting from motion or shock, and static acceleration, such as tilt, and allows selectable full-scale acceleration measurements in ranges of ±2g, ±4g, and ±8g with a resolution of 0.25mg/LSB on the ±2g range. Acceleration is reported digitally, communicating via either the SPI or the I2C protocol and providing 14-bit output resolution.

The ADXL367 has three operating modes: Measurement mode for continuous wide-bandwidth sensing, Wake-up mode for limited bandwidth activity detection, and Standby mode for power conservation. Measurement mode represents its normal operating mode, and in this mode, acceleration data is read continuously, while the Wake-Up mode is ideal for simple detection of the presence or absence of motion at low power consumption. Wake-up mode helps implement a motion-activated ON/OFF switch, allowing the rest of the system to Power-Down until the activity is detected. In addition, the Standby mode suspends measurement and reduces power consumption.

The Accel 22 Click Board™ allows using both I2C and SPI interfaces. The selection can be made by positioning SMD jumpers labelled as COMM SEL in an appropriate position. 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 ADXL367 allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labelled ADDR SEL.

The Accel 22 Click Board™ also possesses two register-configurated interrupt pins, I1 and I2, routed to the INT and AN pins on the mikroBUS™, which has a dual function that can trigger interrupts to alert the host of certain status conditions. They can be used as classic interrupt pins to signal MCU that an event has been sensed or can be used, e.g., I1 as an input for external clocking and I2 as input for synchronized sampling. One or both of these alternate functions can be used concurrently; however, if an interrupt pin is used for its alternate function, it cannot simultaneously be used for its primary function, to signal interrupts.

The ADXL367 incorporates a 14-bit analog-to-digital converter (ADC) to digitize the external analog signal, connected to a header at the top of the board, which is unpopulated by default. The ADC converts analog inputs ranging from 10% to 90% of the internally regulated voltage, limiting the external ADC's input range to a maximum of 1V.

The Accel 22 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 of the Accel 22 Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Interput 2	I2	1	AN	PWM	16	NC
NC	2	RST	INT	15	I1	Interrupt 1
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	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

ONBOARD SETTINGS AND INDICATORS

ACCEL 22 CLICK ELECTRICAL SPECIFICATIONS