Bring your signals to life with AD7175-8 and ATmega2560
Unlock the digital dimension
Published Feb 14, 2024
Click board™
ADC 4 Click
Dev. board
Arduino Mega 2560 Rev3
Compiler
NECTO Studio
MCU
ATmega2560
Transform your designs with the accuracy and reliability of our Analog-To-Digital converter
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Hardware Overview
How does it work?
ADC 4 Click is based on the AD7175-8 IC, a 24bit low noise, fast settling, multiplexed 8/16-channel sigma-delta analog-to-digital converter from Analog Devices. This integrated circuit allows for several different working modes and input connection configurations, giving much flexibility to work with. The ADC 4 Click can work in 16-bit or 24-bit mode, depending on the required precision. It can use single-ended connections with one common pin or differential pair connections, allowing for any combination between the two types of inputs. The AD7175-8 features analog and digital signal conditioning blocks; every channel can be individually set up to use them. Some of these features include various filters (sinc3, sinc5 + sinc1, enhanced 50/60Hz filters), adjustable gain, offset, and more. Besides the 16 input channel registers used to turn the channel off or on and select the differential pairs, there are also 8 "setups" consisting of four registers. Each setup contains one setup config register, filter, gain, and offset register. These registers adjust various conversion settings, such as the reference voltage source, filter type, the buffers on the input channels, the output sample rate, offset and gain for the channels, and more. Although there are only eight setups, the same setup can be applied to several input channels. This simplifies and speeds up the input channel configuration. The input channels are connected to the ADC via the internal crosspoint multiplexer. This multiplexer is used to select the channel connected to the converter.
If more than one input channel is enabled, the multiplexer will cycle through all the enabled inputs automatically. Depending on the selected operational mode, it will stop or continuously cycle through these channels. It has a maximum channel scan rate of 50 kSPS (20 μs) on multiple channels or 250 kSPS (20 μs) on a single channel for fully settled data. The Click board™ uses the SPI interface for communication with the MCU. The MISO line of the mikroBUS™ is routed to the DOUT/RDY pin of the ADC, and besides the SPI data output, it is also used as the indicator of the ready status of the sampled data: whenever the data is ready to be read, this pin is pulled low. More information about properly reading data from the ADC can be found in the AD7175-8 datasheet. Also, MIKROE provides libraries that allow simple and easy reading of the data registers, as demonstrated in the provided demo application. Besides the SPI lines, the #ERROR line is also routed to the INT pin of the mikroBUS™. The config register can set the behavior of this pin. In addition to being the #ERROR output, this pin can also be configured as the input pin, which can be used for stacking error signals from other devices. In this case, the error is signalized by the appropriate bit in the status register. This pin can also be used as the GPIO for some custom user-defined functions. To further improve the sampling accuracy and reliability, the AD7175-8 IC features a temperature sensor. This sensor can be used to measure the ambient temperature.
For example, if the ambient temperature changes significantly, invoking a recalibration routine is possible, providing continuous reliability over different temperature ranges. The temperature sensor can be selected the same way as any other channel by the crosspoint multiplexer. Besides the reference voltage provided by the AD7175-8's integrated LDO, an external LDO can also be used as a reference voltage source, the LT6656 from Analog Devices, a precise voltage regulator that provides low noise and low drop-out voltage reference of 4.096V. Switching the position of the VREF SMD jumper makes it possible to change the external reference voltage applied to the REF+ pin of the ADC between 2.5V and 4.096V. REF- pin is hardwired to the GND. The ADC can also use a custom voltage reference on the REF2+ and REF2- inputs, multiplexed with the AIN0 (A0) and AIN1 (A1) input pins. Finally, the desired reference voltage source can be selected by setting the appropriate bits in the configuration registers of the AD7175-8. The voltage level of the logic section can be selected via the IOVDD SMD jumper between 3.3V and 5V. This allows both 3.3V and 5V capable MCUs to properly use the SPI communication lines. The IOVDD is 3.3V by default, but the device requires 5V from the mikroBUS™ for proper operation. All input channels can be easily connected to the two nine-pole spring action block terminals without additional tools, such as screwdrivers.
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.
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
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Arduino Mega 2560 Rev3 as your development board.
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 ADC 4 Click driver.
Key functions:
adc4_get_err_pinError check functionadc4_get_configGet configuration functionadc4_get_voltageGet voltage function
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 Adc4 Click example
*
* # Description
* This application is a converter from analog to digital multichannel
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes ADC 4 driver and setups working mode.
*
* ## Application Task
* Sequential read of voltage. Information about
* current voltage is logget to UART. Operation is repeated each second. Settings are set
* to calculate and convert input voltage from CH0 with external referent voltage set by VREF jumper on the click board.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "adc4.h"
// ------------------------------------------------------------------ VARIABLES
static adc4_t adc4;
static log_t logger;
static uint16_t voltage;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
adc4_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.
adc4_cfg_setup( &cfg );
ADC4_MAP_MIKROBUS( cfg, MIKROBUS_1 );
adc4_init( &adc4, &cfg );
Delay_ms( 100 );
adc4_default_cfg( &adc4 );
voltage = 0;
}
void application_task ( )
{
voltage = adc4_get_voltage( &adc4, ADC4_VREF_4000MV);
if ( adc4.sing_bit == 1 )
{
log_printf( &logger, "Voltage at CH0 : %d mV \r\n", voltage );
}
else
{
log_printf( &logger, "Voltage at CH0 : - %d mV \r\n", voltage );
}
Delay_ms( 1000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:ADC
