RS485 Isolator click

How does it work?

RS485 Isolator Click is based on the ADM2682E, a signal, and a power-isolated RS-485 transceiver with ESD protection from Analog Devices. The signal isolation is implemented on the interface's logic side, which is achieved by having a digital isolation section and a transceiver section. The applied data to the RX and DE pins are referenced to a logic ground and coupled across an isolated barrier to appear at the transceiver section referenced to the isolated ground. Similarly, the single-ended receiver output signal, referenced to isolated ground in the transceiver section, is coupled across the isolation barrier to appear at the RX pin referenced to logic ground.

RS485 Isolator Click uses a standard 2-Wire UART interface to communicate with the host MCU. There is driver enable input DE, which enables the driver with logic HIGH. The receiver enable input RE, enables the receiver with a LOW logic state. A TERM jumper adds a 120R termination resistor at the receiver side of the bus, which minimizes the reflections. The input/output terminal is labeled A/B for receiver input and Z/Y for driver output.

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.

Specifications

Pinout diagram

This table shows how the pinout on RS485 Isolator click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
Receiver Enable	RE	2	RST	INT	15	NC
Driver Enable	DE	3	CS	RX	14	TX	UART TX
	NC	4	SCK	TX	13	RX	UART RX
	NC	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

RS485 Isolator click electrical specifications

Software Support

We provide a library for the RS485 Isolator Click as well as a demo application (example), developed using MIKROE compilers. The demo can run on all the main MIKROE development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on MIKROE github account.

Library Description

This library contains API for RS485 Isolator Click driver.

Key functions

• rs485isolator_set_receiver_mode Set receiver state

• rs485isolator_generic_read Generic read function.

• rs485isolator_generic_write Generic write function.

Example Description

This example reads and processes data from RS485 Isolator clicks.

 void application_task ( void ) 
 { 
 #ifdef DEMO_APP_TRANSMITTER 
     rs485isolator_generic_write( &rs485isolator, TEXT_TO_SEND, strlen ( TEXT_TO_SEND ) ); 
     log_info( &logger, "---- Data sent ----" ); 
     Delay_ms ( 1000 );
     Delay_ms ( 1000 ); 
 #else 
     rs485isolator_process( ); 
 #endif     
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on MIKROE github account.

Other MIKROE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Rs485Isolator

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK - MIKROE Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.