MIC 3 Click

The MIC 3 Click based on the SSM2167-1RMZ-R7 from Analog Devices is a complete and flexible solution for conditioning microphone inputs in personal electronics and computer audio systems. The Click board™ is also excellent for improving vocal clarity in communications and public address systems. A low noise voltage-controlled amplifier (VCA) provides a gain that is dynamically adjusted by a control loop to maintain a set compression characteristic. The MIC 3 Click provides two operation settings, these settings are selectable with NOISE G. COMPR. jumpers.

How does it work?

The MIC 3 Click provides four different preset values of the noise gate threshold. Experiment with these values by varying the gate. The noise gate threshold is a programmable point using an external resistor. The downward expansion threshold may be set between −40 dBV and −55 dBV, as shown in Table.

The Click board™ provides four different preset values of the compression ratio. Changing the scaling of the control signal fed to the VCA causes a change in the circuit compression ratio.Lowering RCOMP gives smaller compression ratios as indicated in Table. Automatic Gain Control (AGC) performance is achieved with compression ratios between 2:1 and 10:1, and is dependent on the application. Shorting RCOMP disables the AGC function, setting the compression equal to 1:1.

The MIC 3 Click is designed to work with either 3.3V or 5V power supply. It communicates with the target MCU over GPIO pin on the mikroBUS™. The supply current of the SSM2167 can be reduced to under 10 μA by applying an active low.

Specifications

Pinout diagram

This table shows how the pinout on MIC 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	NC
Shutdown	SHD	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Software Support

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

Library Description

Library provides function for setting state of the pin, and function for GPIO mapping.

Key functions:

• void mic3_set_shd_pin ( uint8_t state ) – Function for setting shd pin state

Examples description

The application is composed of three sections :

• System Initialization – Initialization of SHD to output and log module
• Application Initialization – Maps GPIO for mikroBUS 1, and sets SHD pin to HIGH state

void application_init ( )
{
    mikrobus_logWrite( " ***** APP INIT ***** ", _LOG_LINE );
    mic3_gpio_driver_init( (mic3_obj_t)&_MIKROBUS1_GPIO );
    mic3_set_shd_pin( MIC3_PIN_STATE_HIGH );
    mikrobus_logWrite( " ***** APP TASK ***** ", _LOG_LINE );
    mikrobus_logWrite( " - Microphone is turned on - ", _LOG_LINE );
}

The full application code, and ready to use projects can be found on our LibStock page.

Other Mikroe Libraries used in the example:

• UART

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. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.

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.