RS485 5 click

The RS485 5 Click is a Click board™ equipped with the MAX485, low-power, slew-rate-limited transceiver for RS-485 and RS-422 communication, from Maxim Integrated. This device supports half-duplex RS-485 communication and can be used as an interface between the TTL level UART and the RS485 communication bus.

click Product page

Click library

• Author : MikroE Team
• Date : Jun 2020.
• Type : UART type

Software Support

We provide a library for the Rs4855 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly form compilers IDE(recommended way), or downloaded from our LibStock, or found on mikroE github account.

Library Description

This library contains API for Rs4855 Click driver.

Standard key functions :

• Config Object Initialization function.

  void rs4855_cfg_setup ( rs4855_cfg_t *cfg );

• Initialization function.

  RS4855_RETVAL rs4855_init ( rs4855_t ctx, rs4855_cfg_t cfg );

Example key functions :

• Generic write function.

  void rs4855_generic_write ( rs4855_t ctx, char data_buf, uint16_t len );

• Sets DE pin to high or low state

  void rs4855_set_de_state( rs4855_t *ctx, uint8_t state );

• Sets RE pin to high or low state

  void rs4855_set_re_state( rs4855_t *ctx, uint8_t state );

Examples Description

This example reads and processes data from RS485 5 clicks.

The demo application is composed of two sections :

Application Init

Initializes the driver and enables the selected mode.

void application_init ( void )
{
    log_cfg_t log_cfg;
    rs4855_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.

    rs4855_cfg_setup( &cfg );
    RS4855_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rs4855_init( &rs4855, &cfg );

    Delay_ms ( 100 );

#ifdef DEMO_APP_RECEIVER
    rs4855_set_re_state( &rs4855, RS4855_PIN_STATE_LOW );
    rs4855_set_de_state( &rs4855, RS4855_PIN_STATE_LOW );
    log_info( &logger, "---- Receiver mode ----" );
#endif    
#ifdef DEMO_APP_TRANSMITTER
    rs4855_set_re_state( &rs4855, RS4855_PIN_STATE_HIGH );
    rs4855_set_de_state( &rs4855, RS4855_PIN_STATE_HIGH );
    log_info( &logger, "---- Transmitter mode ----" );
#endif    
}

Application Task

Depending on the selected mode, it reads all the received data or sends the desired message every 2 seconds.

void application_task ( void )
{
#ifdef DEMO_APP_RECEIVER
    rs4855_process( );
#endif    

#ifdef DEMO_APP_TRANSMITTER
    rs4855_generic_write( &rs4855, TEXT_TO_SEND, 8 );
    log_info( &logger, "---- Data sent ----" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#endif  
}

The full application code, and ready to use projects can be installed directly form compilers IDE(recommneded) or found on LibStock page or mikroE GitHub accaunt.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Rs4855

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. The terminal available in all Mikroelektronika compilers, or any other terminal application of your choice, can be used to read the message.