Intermediate
20 min

Collect and transmit data across vast distances with RN2903 and PIC32MZ2048EFM100

915MHz long-range transceivers: Your bridge to the future

LR 2 Click with Curiosity PIC32 MZ EF

Published Nov 09, 2023

Click board™

LR 2 Click

Dev Board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

With our 915MHz transceiver, you can unlock new possibilities in agriculture, environmental monitoring, and industrial control, thanks to their exceptional range and penetration capabilities.

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Hardware Overview

How does it work?

LR 2 Click is based on the RN2903, a low-power, long-range RF technology-based transceiver module from Microchip Technology. It features the Class A LoRaWAN compliant stack, optimized for robust LoRaWAN networking, immune to interferences, and suitable for long-range wireless operation. It offers a long-range spread spectrum communication with high interference immunity. A receiver with a sensitivity of -148dBm combined with the 18.5dBm integrated amplifier allows for extended range links that can achieve up to 15km in an open area (by the module manufacturer specification). This Click board™ offers data rates of 300kbps with FSK modulation and 12500bps with LoRa Technology modulation and is associated with the 915MHz ISM band suitable for applications in the United States, Canada, Australia, and New Zealand. To join a LoRaWAN network, the RN2903 requires a LoRaWAN concentrator/gateway. The endpoint device has to

use a unique endpoint address, an application session key, and a network session key. The first method is called over-the-air activation (OTAA), where these keys are issued after a specific join procedure. The second method is to assign these keys manually, using UART commands. This method is called activation by personalization (ABP) and can be prone to some security issues. In any case, before an end device can communicate on the LoRaWAN network, it must be activated. LR 2 Click communicates with MCU using the UART interface with commonly used UART RX and TX pins, including the hardware flow control pins CTS and RTS (Clear to Send, Ready to Send) at data rates up to 57600bps for the data transfer. There are three groups of commands used to configure and operate the separate layers of the RN2903 (SYSTEM, MAC, and RADIO). Each layer controls a specific area of the module, and every UART command starts with one of the three keywords,

which represent an abbreviation of the layer name they are controlling. The module also has a non-volatile memory (EEPROM) for storing the configuration settings and some additional data. Also, this Click board™ can be reset through the Hardware Reset pin, labeled as RST on the mikroBUS™ socket, by setting this pin to a low logic state. LR 2 Click features the SMA antenna connector with an impedance of 50Ω, so it can be equipped with the appropriate 915MHz compliant antenna that MIKROE offers. 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.

LR 2 Click hardware overview image

Features overview

Development board

Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand

functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,

which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.

Curiosity PIC32MZ EF double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

You complete me!

Accessories

Rubber Antenna GSM/GPRS Right Angle is the perfect companion for all GSM Click boards™ in our extensive lineup. This specialized antenna is designed to optimize your wireless connectivity with impressive features. With a wide frequency range spanning 824-894/1710-1990MHz or 890-960/1710-1890MHz, it can handle various frequency bands, ensuring a seamless and reliable connection. The antenna boasts an impedance of 50 Ohms and a gain of 2dB, enhancing signal reception and transmission. Its 70/180MHz bandwidth provides flexibility for diverse applications. The vertical polarization further enhances its performance. With a maximum input power capacity of 50W, this antenna ensures robust communication even under demanding conditions. Measuring a compact 50mm in length and featuring an SMA male connector, the Rubber Antenna GSM/GPRS Right Angle is a versatile and compact solution for your wireless communication needs.

LR 2 Click accessories image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RA9
RST
UART RTS
RPD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
UART CTS
RF13
INT
UART TX
RPD10
TX
UART RX
RPD15
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

LR 2 Click Schematic schematic

Step by step

Project assembly

Curiosity PIC32MZ EF front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.

Curiosity PIC32MZ EF front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Curiosity PIC32 MZ EF MB 1 Access - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Curiosity PIC32 MZ EF MCU Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output via Debug Mode

1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.

2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.

DEBUG_Application_Output

Software Support

Library Description

This library contains API for LR 2 Click driver.

Key functions:

  • lr_mac_tx - Function for writing mac parameters

  • lr_join - Function for setting join mode

  • lr_tick_conf - Timer Configuration

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * @file main.c
 * @brief LR Click Example.
 *
 * # Description
 * This example reads and processes data from LR clicks.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver init and LR init.
 * 
 * ## Application Task  
 * Transmitter mode - sends one by one byte sequence of the desired message each second and 
 * checks if it is sent successfully.
 * Receiver mode - displays all the received characters on USB UART.
 * 
 * ## Additional Functions
 * - lr_process ( ) - The general process of collecting data the module sends.
 * - bool is_digit ( char c ) - Checks if input is a digit 
 * - hex_to_int ( char* origin, uint8_t* result ) - Converts hexadecimal to int value.
 *
 * @author Stefan Ilic
 *
 */


#include "board.h"
#include "log.h"
#include "lr.h"
#include "string.h"
#include "conversions.h"

#define PROCESS_COUNTER 5
#define PROCESS_RX_BUFFER_SIZE 300

// ------------------------------------------------------------------ VARIABLES

#define DEMO_APP_RECEIVER
//#define DEMO_APP_TRANSMITTER

static lr_t lr;
static log_t logger;

uint8_t cnt;
uint8_t send_data;
int8_t  int_data;
uint8_t rx_state;
uint8_t tx_state;

char send_hex[ 50 ];
char tmp_txt[ 50 ];
uint8_t send_message[ 9 ] = { 'M', 'i', 'k', 'r', 'o', 'E', 13, 10, 0 };

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

static void lr_process ( void ) {
    int32_t rsp_size;
    
    char uart_rx_buffer[ PROCESS_RX_BUFFER_SIZE ] = { 0 };
    uint8_t check_buf_cnt;
    uint8_t process_cnt = PROCESS_COUNTER;
    
    while ( process_cnt != 0 ) {
        rsp_size = lr_generic_read( &lr, &uart_rx_buffer, PROCESS_RX_BUFFER_SIZE );

        if ( rsp_size > 0 ) {  
            // Validation of the received data
            for ( check_buf_cnt = 0; check_buf_cnt < rsp_size; check_buf_cnt++ ) {
                lr_put_char( &lr, uart_rx_buffer[ check_buf_cnt ] );
                lr_isr_process( &lr );
            }
            
            // Clear RX buffer
            memset( uart_rx_buffer, 0, PROCESS_RX_BUFFER_SIZE );
        } else {
            process_cnt--;
            
            // Process delay 
            Delay_ms( 100 );
        }
    }
}

bool is_digit ( char c ) {
    if ( c >= '0' && c <= '9' ) {
        return true;
    }

    return false;
}

void hex_to_int ( char* origin, uint8_t* result ) {
    uint8_t len = strlen( origin );
    uint8_t idx, ptr, factor;

    if ( len > 0 ) {
        *result = 0;
        factor = 1;

        for ( idx = len - 1; idx >= 0; idx-- ) {
            if ( is_digit( *( origin + idx ) ) ) {
                *result += ( *( origin + idx ) - '0' ) * factor;
               } else {
                    if ( *( origin + idx ) >= 'A' && *( origin + idx ) <= 'Z' ) {
                        
                        ptr = ( *( origin + idx ) - 'A' ) + 10;
                        
                    } else {
                        return;
                    }
                    *result += ( ptr * factor );
                }
                factor *= 16;
          }
     }
}

void lr_cbk( char* response ) {
}

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void ) {
    log_cfg_t log_cfg;
    lr_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.

    lr_cfg_setup( &cfg );
    LR_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    lr_init( &lr, &cfg );

    lr_default_cfg( &lr, 0, &lr_cbk );

    lr_cmd( &lr, LR_CMD_SYS_GET_VER, &tmp_txt[ 0 ] );

    lr_cmd( &lr, LR_CMD_MAC_PAUSE,  &tmp_txt[ 0 ] );
    log_printf( &logger, "mac pause\r\n" );
    for ( cnt = 0; cnt < 10; cnt++ ) {
        log_printf( &logger, "%c", tmp_txt[ cnt ] );
    }

    log_printf( &logger, "\r\n" );

    lr_cmd( &lr, LR_CMD_RADIO_SET_WDT, &tmp_txt[ 0 ] );

    log_printf( &logger, "radio set wdt 0\r\n" );
    log_printf( &logger, "%s\r\n", &tmp_txt[ 0 ] );
}

void application_task ( void ) {
    char *ptr;
    lr_process( );
    
#ifdef DEMO_APP_RECEIVER
    rx_state = lr_rx( &lr, LR_ARG_0, &tmp_txt[ 0 ] );
    if ( rx_state == 0 ) {
        tmp_txt[ 12 ] = 0;
        ptr = ( char* )&int_data;
        hex_to_int( &tmp_txt[ 10 ], ptr );

        log_printf( &logger, "%c", int_data  );
    }
#endif

#ifdef DEMO_APP_TRANSMITTER
    for ( cnt = 0; cnt < 9; cnt++ ) {
        send_data = send_message[ cnt ] ;
        int8_to_hex( send_data, send_hex );
        tx_state = lr_tx( &lr, &send_hex[ 0 ] );
        if ( tx_state == 0 ) {
            log_printf( &logger, "  Response : %s\r\n", &tmp_txt[ 0 ] );
        }
        Delay_ms( 1000 );
    }
#endif
}

void main ( void ) {
    application_init( );

    for ( ; ; ) {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END

Additional Support

Resources

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