Translate 24V sensor outputs to 5V CMOS-compatible signals with MAX31910 and PIC32MZ2048EFM100
Your gateway to industrial signal serialization
Published Sep 30, 2023
Click board™
Serializer Click
Dev Board
Curiosity PIC32 MZ EF
Compiler
NECTO Studio
MCU
PIC32MZ2048EFM100
The purpose of this solution is to simplify the complexity of sensor data conversion, empowering your automation projects with efficient 5V CMOS-compatible signals
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Hardware Overview
How does it work?
Serializer Click is based on the MAX31910, an eight-channel digital input translator/serializer for high-channel density digital input modules in industrial and process automation from Maxim Integrated, now part of Analog Devices. It features integrated current limiting, low-pass filtering, and channel serialization. Input current limiting allows a significant power reduction consumed from the field voltage supply (external typical 24V) compared to traditional discrete resistor-divider implementations. The device uses patent-pending circuit techniques to reduce power beyond possible input current, further limiting alone. The MAX31910 translates, conditions, and serializes the 24V digital output of sensors and switches to 5V CMOS-compatible signals required by the MCU. It provides the front-end interface circuit of a
programmable logic controller (PLC) digital input module. Selectable on-chip low-pass filters allow flexible debouncing and filtering sensor outputs based on the application. The serializer is stackable so that any number of input channels (IN1-IN8) can be serialized and output through only one SPI-compatible port. The serializer inputs (IN1-IN8) sense field sensors' state (ON vs. OFF) by monitoring both voltage and current flowing through the sensor output. The current sinking through these input pins rises linearly with input voltage until the limit set by the current clamp is reached (set by an onboard potentiometer). Any voltage increase beyond this point does not further increase the input current. Serializer Click communicates with MCU through a standard SPI interface in a configuration with installed digital
isolators (ISO7741 and LTV-817S). Also, it uses an interrupt pin, the FLT pin of the mikroBUS™ socket, as a 'fault' indicator, which immediately notifies the host when a fault such as an overtemperature or undervoltage condition occurs. It also has a two-channel switch labeled DB, determining the current switching frequency. The current switching clock period is automatically selected according to a switch position. 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. Also, this 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
Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand
functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,
which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC32
MCU Memory (KB)
2048
Silicon Vendor
Microchip
Pin count
100
RAM (Bytes)
524288
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.
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.
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™.
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.
Software Support
Library Description
This library contains API for Serializer Click driver.
Key functions:
serializer_get_flt_pin- This function returns the fault pin logic stateserializer_read_input- This function reads the input data by using SPI serial interface, and then checks the data integrity by verifying the CRC byte.
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 main.c
* @brief Serializer Click example
*
* # Description
* This example demonstrates the use of a Serializer click board by reading
* the state of all inputs and displaying the results on the USB UART.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and logger.
*
* ## Application Task
* Reads the state of all inputs and displays the results on the USB UART
* approximately once per second. Also, if there's any fault indication detected,
* it will be displayed accordingly.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "serializer.h"
static serializer_t serializer;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
serializer_cfg_t serializer_cfg; /**< Click config object. */
/**
* 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.
serializer_cfg_setup( &serializer_cfg );
SERIALIZER_MAP_MIKROBUS( serializer_cfg, MIKROBUS_1 );
if ( SPI_MASTER_ERROR == serializer_init( &serializer, &serializer_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
uint8_t input_data = 0;
err_t status = serializer_read_input ( &serializer, &input_data );
if ( SERIALIZER_ERROR != status )
{
for ( uint8_t cnt = 0; cnt < 8; cnt++ )
{
log_printf( &logger, " IN%u: %s\r\n", ( uint16_t ) cnt + 1,
( char * ) ( ( input_data & ( 1 << cnt ) ) ? "High" : "Low" ) );
}
if ( status & SERIALIZER_STATUS_UNDERVOLTAGE )
{
log_info( &logger, "Undervoltage fault" );
}
if ( status & SERIALIZER_STATUS_OVERTEMPERATURE )
{
log_info( &logger, "Overtemperature fault" );
}
log_printf( &logger, "\r\n" );
Delay_ms( 1000 );
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
