Create the ultimate solution for signal magnification with MCP6S21 and ATmega2560

Amplify with precision

GainAMP 2 click with Arduino Mega 2560 Rev3

Published Feb 14, 2024

Click board™

GainAMP 2 click

Dev. board

Arduino Mega 2560 Rev3

Compiler

NECTO Studio

MCU

ATmega2560

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

Arduino Mega 2560 is a robust microcontroller platform built around the ATmega 2560 chip. It has extensive capabilities and boasts 54 digital input/output pins, including 15 PWM outputs, 16 analog inputs, and 4 UARTs. With a 16MHz crystal

oscillator ensuring precise timing, it offers seamless connectivity via USB, a convenient power jack, an ICSP header, and a reset button. This all-inclusive board simplifies microcontroller projects; connect it to your computer via USB or power it up

using an AC-to-DC adapter or battery. Notably, the Mega 2560 maintains compatibility with a wide range of shields crafted for the Uno, Duemilanove, or Diecimila boards, ensuring versatility and ease of integration.

Arduino Mega 2560 Rev3 double side image

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

256

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

8192

You complete me!

Accessories

Click Shield for Arduino Mega comes equipped with four mikroBUS™ sockets, with two in the form of a Shuttle connector, allowing all the Click board™ devices to be interfaced with the Arduino Mega board with no effort. Featuring an AVR 8-bit microcontroller with advanced RISC architecture, 54 digital I/O pins, and Arduino™ compatibility, the Arduino Mega board offers limitless possibilities for prototyping and creating diverse applications. This board is controlled and powered conveniently through a USB connection to program and debug the Arduino Mega board efficiently out of the box, with an additional USB cable connected to the USB B port on the board. Simplify your project development with the integrated ATmega16U2 programmer and unleash creativity using the extensive I/O options and expansion capabilities. There are eight switches, which you can use as inputs, and eight LEDs, which can be used as outputs of the MEGA2560. In addition, the shield features the MCP1501, a high-precision buffered voltage reference from Microchip. This reference is selected by default over the EXT REF jumper at the bottom of the board. You can choose an external one, as you would usually do with an Arduino Mega board. There is also a GND hook for testing purposes. Four additional LEDs are PWR, LED (standard pin D13), RX, and TX LEDs connected to UART1 (mikroBUS™ 1 socket). This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino Mega board with Click Shield for Arduino Mega, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Used MCU Pins

mikroBUS™ mapper

Signal Output

PF1

RST

SPI Chip Select

PL4

SPI Clock

PB1

SCK

SPI Slave Data OUT

PB3

MISO

SPI Slave Data IN

PB2

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Click Shield for Arduino Mega front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino Mega 2560 Rev3 as your development board.

Arduino Mega 2560 Rev3 front image hardware assembly

Charger 27 Click front image hardware assembly

Charger 27 Click complete accessories setup image hardware assembly

Board mapper by product8 hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

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

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * \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_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    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 );
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

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