30 min

Create the ultimate solution for signal magnification with MCP6S21 and PIC32MX695F512L

Amplify with precision

GainAMP 2 click with UNI Clicker

Published Jun 08, 2023

Click board™

GainAMP 2 click

Development board

UNI Clicker


NECTO Studio



Whether you're working with audio, sensor data, or other low-level signals, our 6-channel programmable gain amplifier is an ideal solution for boosting and optimizing signal quality



Hardware Overview

How does it work?

GainAMP 2 Click is based on the MCP6S21, a rail-to-rail I/O, low noise programmable gain amplifier (PGA) from Microchip. This integrated circuit features six multiplexed non-inverting inputs, with a gain that can be programmed via the SPI interface for each input individually. The channels CH0 to CH5 are the six input channels connected to the external signal sources. The internal multiplexer selects the channel that is gained and sent to the output pin. The gain stage of the MCP6S21 has eight different discrete steps of gain: 1, 2, 4, 5, 8, 10, 16, and 32V/V. The rail-to-rail inputs and outputs accept voltage levels up to VCC with no distortions or phase shifting. The output voltage is offset by the resistor ladder network on

the output stage and the voltage on the voltage reference pin. Besides the VOUT pin on the ten-pole I/O connector, the MCP6S21 output pin is also routed to the AN pin of the mikroBUS™ so it can be used as the input signal for the ADC. This allows the amplified signal to be easily digitalized and processed by the MCU. Using the click board in this configuration effectively turns the GainAMP 2 click into an analog port expander with the selectable gain on its inputs. The MCP6S21 device can be put in a shutdown mode by setting the appropriate bits of the internal register via the SPI interface. While in shutdown mode, the power consumption is minimal. The device stays in Shutdown mode until a valid command is received

via the SPI. While in the shutdown mode, the device remembers the states of the internal registers, so when it awakens, it will resume working as before. The internal registers can be easily accessed by using MIKROE library functions. More information about the registers and their settings can be found in the MCP6S21 datasheet. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.


Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU



8th Generation



MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Signal Output
SPI Chip Select
SPI Clock
SPI Slave Data OUT
SPI Slave Data IN
Power Supply
Power Supply

Take a closer look


GainAMP 2 click Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
UNI Clicker Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for GainAMP 2 Click driver.

Key functions:

  • gainamp2_set_channel_gain - Set the channel gain

  • gainamp2_get_voltage - Return voltage measured from VOUT pin

  • gainamp2_write_Command - Send Command

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

 * \file 
 * \brief GainAmp2 Click example
 * # Description
 * This application is programmable gain amplifier
 * The demo application is composed of two sections :
 * ## Application Init 
 * Initializes and sets GainAMP 2 click channel 0 to amplify the signal 2 times
 * ## Application Task  
 * Displays the voltage measured from VOUT pin
 * \author MikroE Team
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "gainamp2.h"

// ------------------------------------------------------------------ VARIABLES

static gainamp2_t gainamp2;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
    log_cfg_t log_cfg;
    gainamp2_cfg_t cfg;

     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, "---- Application Init ----" );

    //  Click initialization.

    gainamp2_cfg_setup( &cfg );
    gainamp2_init( &gainamp2, &cfg );
    gainamp2_set_channel_gain ( &gainamp2, GAINAMP2_CH0, GAINAMP2_GAIN_2X );
    log_printf( &logger,"Channel 0 - aplified 2x \r\n" ); 

void application_task( void )
    log_printf( &logger,"Voltage at VOUT: %f \r\n", gainamp2_get_voltage( &gainamp2 ) );
    log_printf( &logger,"------------------------------- \r\n " );
    Delay_ms( 1000 );

void main ( void )
    application_init( );

    for ( ; ; )
    	application_task( );


// ------------------------------------------------------------------------ END

Additional Support