Provide galvanic isolation between the transmitter and receiver for enhanced electrical safety with ISO1450 and STM32F407VGT6
5kVRMS isolated half-duplex RS-485 transceiver
Published Nov 06, 2024
Click board™
RS485 Isolator 4 Click
Dev. board
Discovery kit with STM32F407VG MCU
Compiler
NECTO Studio
MCU
STM32F407VGT6
Reliable, isolated RS-485 communication with robust protection for industrial environments like grid infrastructure, motor drives, and building automation
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Hardware Overview
How does it work?
RS485 Isolator 4 Click is based on the ISO1450, an isolated half-duplex RS-485 transceiver from Texas Instruments. This transceiver is designed to provide galvanic isolation for RS-485 and RS-422 communication, offering robust noise immunity essential for harsh industrial environments. The ISO1450's bus pins are engineered to withstand high levels of electrostatic discharge (ESD) and electrical fast transients (EFT), eliminating the need for additional external components to ensure system-level protection. This capability makes the Click board™ ideal for industrial and commercial communication needs such as grid infrastructure, solar inverters, motor drives, HVAC systems, and building automation. With support for data rates up to 50Mbps, the ISO1450 enables long-distance communication while maintaining signal integrity. Its silicon-dioxide capacitive isolation barrier
provides a reliable 5kVRMS isolation for 1 minute, as per UL 1577 standards, and a working voltage of 1500VPK. This isolation feature breaks ground loops between communicating nodes, allowing a wider common-mode voltage range. The ISO1450's isolated side can operate over a broad supply voltage range of 3V to 5.5V, removing the need for a regulated supply on this side. The ISO1450 also includes advanced failsafe features to protect against invalid bus states, such as open bus conditions from broken cables, shorted bus conditions due to insulation breakdowns, and idle bus conditions where no driver is actively transmitting. This ensures reliable operation, even when communication lines encounter physical issues. In addition to the standard UART interface TX and RX pins from the mikroBUS™ socket, RS485 Isolator 4 Click also features receiver and
driver enable pins, routed to the RE and DE pins of the mikroBUS™. In this half-duplex implementation, the driver and receiver enable pins allow any connected node on the J1 header to be configured as either transmitting or receiving at any given moment. This flexibility reduces the need for additional cables since it allows dynamic switching between transmit and receive modes on the same communication line. 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
Discovery kit with STM32F407VG MCU, powered by the STM32F407 microcontroller, simplifies audio application development. It offers a robust platform with features like the ST-LINK/V2-A debugger, STMEMS digital accelerometer, digital microphone, and integrated audio DAC with a class D speaker driver. It has LEDs, push buttons, and a USB OTG
Micro-AB connector for versatile connectivity. The STM32F407VGT6 MCU boasts a 32-bit Arm Cortex-M4 with FPU, 1MB Flash memory, and 192KB RAM, housed in an LQFP100 package. Equipped with USB OTG FS, MEMS accelerometer, omnidirectional digital microphone, and user-friendly buttons, it ensures seamless operation.
The board accommodates various add-ons via extension headers while offering flexible power supply options, including ST-LINK, USB VBUS, or external sources. Supported by comprehensive free software and a range of IDEs, it empowers developers with flexibility and ease of use, making it an ideal choice for audio-centric projects.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
10
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
100
You complete me!
Accessories
STM32F4 Discovery Shield is the perfect extension for your STM32F4 Discovery Board from STMicroelectronics. This versatile shield features four mikroBUS™ host sockets, a USB-UART module, and a CAN transceiver, expanding the capabilities of your Discovery board. Acting as a docking station, the STM32F4 Discovery Shield enables you to effortlessly transform your board into various applications, whether it's an RFID lock, SMS-triggered control switch, GPS tracking device, full-blown weather station, or any other idea you have in mind. With its seamless integration and enhanced functionality, this shield empowers you to explore endless possibilities and quickly bring your projects to life.
Wire Jumpers Male to Male (15 cm length, 10pcs) is a set of high-quality jumper wires designed for easy prototyping and testing. Each wire in the set is 15cm long, with male connectors on both ends, allowing an easy connection between components on breadboards or other electronic projects. The set includes ten wires in different colors, providing clear identification and organization in your circuit. These wire jumpers are ideal for DIY projects, setups, and other electronic applications where quick, reliable connections are required.
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 Discovery kit with STM32F407VG MCU 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 RS485 Isolator 4 Click driver.
Key functions:
rs485isolator4_generic_write- This function writes a desired number of data bytes by using UART serial interface.rs485isolator4_generic_read- This function reads a desired number of data bytes by using UART serial interface.rs485isolator4_driver_enable- This function enables the driver input by setting the DE pin to high logic state.
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 main.c
* @brief RS485 Isolator 4 Click Example.
*
* # Description
* This example demonstrates the use of an RS485 Isolator 4 Click board by showing
* the communication between the two Click board configured as a receiver and transmitter.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and logger and displays the selected application mode.
*
* ## Application Task
* Depending on the selected mode, it reads all the received data or sends the desired
* message every 2 seconds.
*
* @note
* Make sure to provide a power supply voltage to isolated VCC_EXT and GND pins
* in a range from 3V to 5.5V.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "rs485isolator4.h"
// Comment out the line below in order to switch the application mode to receiver
#define DEMO_APP_TRANSMITTER
#define DEMO_TEXT_MESSAGE "MIKROE - RS485 Isolator 4 Click board\r\n"
static rs485isolator4_t rs485isolator4;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
rs485isolator4_cfg_t rs485isolator4_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.
rs485isolator4_cfg_setup( &rs485isolator4_cfg );
RS485ISOLATOR4_MAP_MIKROBUS( rs485isolator4_cfg, MIKROBUS_1 );
if ( UART_ERROR == rs485isolator4_init( &rs485isolator4, &rs485isolator4_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
#ifdef DEMO_APP_TRANSMITTER
rs485isolator4_driver_enable ( &rs485isolator4 );
rs485isolator4_receiver_disable ( &rs485isolator4 );
log_printf( &logger, " Application Mode: Transmitter\r\n" );
#else
rs485isolator4_driver_disable ( &rs485isolator4 );
rs485isolator4_receiver_enable ( &rs485isolator4 );
log_printf( &logger, " Application Mode: Receiver\r\n" );
#endif
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
#ifdef DEMO_APP_TRANSMITTER
rs485isolator4_generic_write( &rs485isolator4, DEMO_TEXT_MESSAGE, strlen( DEMO_TEXT_MESSAGE ) );
log_printf( &logger, "%s", ( char * ) DEMO_TEXT_MESSAGE );
Delay_ms( 1000 );
Delay_ms( 1000 );
#else
uint8_t rx_data = 0;
if ( rs485isolator4_generic_read( &rs485isolator4, &rx_data, 1 ) > 0 )
{
log_printf( &logger, "%c", rx_data );
}
#endif
}
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
Additional Support
Resources
Category:RS485
