M-BUS RF 3 Click

How does it work?

M-BUS RF 3 Click is based on the Metis-II (2607021183000), a high-power radio module from Würth Elektronik, operating at 868MHz. This module integrates an MSP430 microcontroller and a CC1125 RF chip-set, offering an efficient and cost-effective communication solution. The Metis-II module adheres to the Wireless M-BUS EN13757-4:2013 standard and supports the Open Metering System (OMS), ensuring wide compatibility in utility metering applications. An increased RF output power of +14dBm and sensitivity up to -106dBm enables reliable wireless communication over distances up to 1000 meters in line-of-sight conditions. Designed with energy efficiency in mind, the module includes low-power functions such as Wake-On-Radio and adjustable RF data rates, making it ideal for long-range, low-power wireless applications. Additionally, it features AES-128 encryption for secure data transmission, ensuring robust communication for metering systems.

Communication between the Metis-II and the host MCU is made through a UART interface, using the standard UART RX and TX pins and hardware flow control pins (CTS/RTS). The module communicates at 115200bps by default, allowing efficient data exchange. The board includes a reset pin (RST) and a RESET button for resetting the module, and two LED indicators for user interaction: an orange TX LED signaling transmission activity and a yellow RX LED indicating reception.

In addition to the UART interface, this Click board™ also features a USB Type-C connector, enabling power supply and configuration through a PC. This is made possible by the CP2102N, a highly integrated USB-to-UART bridge, and the NCP1117 LDO regulator, which converts the USB supply to the required 3.3V for the module allowing for standalone operation.

The board is designed to interface with 868MHz antennas, such as the Rubber 868MHz Antenna offered by MIKROE. It includes a u.Fl connector, necessitating an IPEX-SMA cable adapter, also available from MIKROE, to ensure proper antenna connection.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing 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 M-BUS RF 3 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
Reset	RST	2	RST	INT	15	RTS	UART RTS
UART CTS / ID COMM	CS	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	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

M-BUS RF 3 Click electrical specifications

Software Support

We provide a library for the M-BUS RF 3 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 M-BUS RF 3 Click driver.

Key functions

• mbusrf3_set_rst_pin This function is used to set reset pin state.

• mbusrf3_send_command This function is used to send a desired command.

• mbusrf3_send_data This function is used to data in transmitter mode.

Example Description

This example demonstrates the use of M-BUS RF 3 Click by processing the incoming data and displaying them on the USB UART.

void application_task ( void )  
 { 
     mbusrf3_example( ); 
 }

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.MBUSRF3

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.