MICRF RX Click

NOTE: Pair the MICRF TX Click with the MICRF RX Click for optimal performance, as both boards are designed to work on the 315MHz frequency. Perfect for developers looking for compatible transmitter and receiver units. Find both Click boards™ available for purchase at the MIKROE shop.

How does it work?

MICRF RX Click is based on the MICRF220, an ASK/OOK receiver with RSSI and squelch from Microchip. This super-heterodyne, image-reject RF receiver is engineered to require only a crystal, in this case, an onboard 9.81563MHz, and a minimal set of external components for operation. Its suitability spans across a variety of applications, such as low-power Remote Keyless Entry (RKE), Tire Pressure Monitoring Systems (TPMS), and remote actuation systems.

In terms of performance, the MICRF220 distinguishes itself with a sensitivity of -110dBm at 1kbps and a 0.1% Bit Error Rate (BER), complemented by four selectable demodulator filter bandwidths ranging from 1170Hz to 9400Hz. Filter bandwidth can be selected by placing BW SEL jumpers in a corresponding position, 0 or 1, choosing the corresponding frequency based on the truth table from the attached MICRF220 datasheet (Table 2.). This feature permits the device to accommodate bit rates as high as 14.4kbps (from 1.8kbps up to 14.4kbps). Operating on a 3.3V supply from the mikroBUS™ power rail, it is optimized for 315MHz operation, drawing a typical supply current of 4.3mA.

Additionally, the MICRF220 also has a low-power shutdown mode controllable through the SH pin, reducing the supply current to an impressive 0.1µA, alongside a squelch function accessed via the SQ pin that minimizes data output activity on the DO pin until valid bits are detected, without compromising receiver sensitivity. The board also incorporates an RSI pin to indicate received signal strength.

For antenna configurations, the board allows for the use of an onboard PCB antenna specifically tuned to 315MHz or an external antenna via an SMA connector, with the selection made possible by adjusting the capacitor from position A to B near the SMA connector.

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 MICRF RX Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Received Signal Strength Monitor	RSI	1	AN	PWM	16	SQ	Squelch Function
Shutdown	SH	2	RST	INT	15	DO	Receiver Data Output
ID COMM	CS	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	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

MICRF RX Click electrical specifications

Software Support

We provide a library for the MICRF RX 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 MICRF RX Click driver.

Key functions

• micrfrx_enable_device This function enables device by setting the SHD pin to low logic state.

• micrfrx_wait_ready This function waits for all training bytes to arrive which indicates data ready.

• micrfrx_read_packet This function reads data packet and stores it in a packet_buf only if the MICRFRX_PREAMBLE bytes are received successfully.

Example Description

This example demonstrates the use of MICRF RX click board by reading and parsing packet messages received from the transmitter.

void application_task ( void ) 
 { 
     static float rssi_v = 0; 
     static uint8_t packet_len = 0; 
     static uint8_t msg_cnt = 0; 
     static uint16_t crc = 0; 

     log_printf( &logger, "rn Waiting for data ready...rn" ); 
     micrfrx_wait_ready ( &micrfrx ); 
     packet_len = micrfrx_read_packet ( &micrfrx ); 
     if ( packet_len ) 
     { 
         micrfrx_read_rssi_voltage ( &micrfrx, &rssi_v ); 
         crc = ( ( uint16_t ) packet_buf[ packet_len - 2 ] << 8 ) | packet_buf[ packet_len - 1 ]; 
         if ( crc == micrftx2_calculate_crc16 ( packet_buf, packet_len - 2 ) ) 
         { 
             log_printf( &logger, " Received message: " ); 
             for ( msg_cnt = 0; msg_cnt < packet_buf[ 2 ]; msg_cnt++ ) 
             { 
                 log_printf( &logger, "%c", ( uint16_t ) packet_buf[ msg_cnt + 3 ] ); 
             } 
             log_printf( &logger, "rn RSSI: %.1f dBmrn", MICRFRX_RSSI_V_TO_DBM ( rssi_v ) ); 
         } 
     } 
     Delay_ms ( 100 ); 
 }

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.MICRFRX

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.