This program is guided to help establish a connection between two RFM95 900MHz LoRa radio modules using Maxim Integrated's Feather MCUs (MAX32630FTHR Mbed and the MAX32620FTHR Mbed). Once the radios are configured after powering on and if the radios are wired correctly, the two radios will self identify as either a master or a slave, and will then proceed to PING and PONG back and forth. Information about what is happening between the radios can be seen if the two boards are hooked up to a USB COM port through the included DAPLINK modules.

Dependencies:   BMI160 BufferedSerial SX1276GenericLib USBDeviceHT max32630fthr

Fork of MAX326xxFTHR_LoRa_RFM95 by Central Applications - Mbed Code repo

RFM95 LoRa Example Ping Pong Program

Getting Started

This program has the support for sx1276 (Adafruit RFM95W LoRa Radio Transceiver Breakout - 900 MHz) and (Adafruit LoRa Radio FeatherWing - RFM95W 900 MHz) to work with a few different mbed boards (see PinMap.h for supported boards). However, this specific program is set up to work with the following mbed boards and RFM95 915MHz LoRa radios and the given pin diagrams without modifications: MAX32620FTHR and MAX32630FTHR.

Configuring the LoRa Radio

The setup for the radio can be found in <<SX1276GenericPingPong/GenericPingPong.cpp>>, which can be found by navigating from the root directory. Setup for the radio starts on line #14 in <<SX1276GenericPingPong/GenericPingPong.cpp>>.

Choosing the Correct Frequency

This program was written with libraries compatible with RFM95 LoRa 900MHz Radio modules. The radio's frequency is able to be tuned dynamically, however this program configures the frequency by programming registers at device power on. The 900MHz module supports both 868MHz and 915MHz operation. Check local laws for which band around 900MHz is set aside for the scientific, commercial, and/or license free usage in your country. The supported frequencies can be found in <<SX1276GenericLib.lib/sx1276/sx1276.h>>

They are also listed below for convenience:

SX1276GenericLib.lib/sx1276/sx1276.h

typedef enum {
    RF_FREQUENCY_868_0 = 868000000, //Hz
    RF_FREQUENCY_868_1 = 868100000, //Hz
    RF_FREQUENCY_868_3 = 868300000, //Hz
    RF_FREQUENCY_868_5 = 868500000, //Hz
    RF_FREQUENCY_915_0 = 915000000, //Hz
    RF_FREQUENCY_915_1 = 915100000, //Hz
    RF_FREQUENCY_915_3 = 915300000, //Hz
    RF_FREQUENCY_915_5 = 915500000, //Hz
} rf_frequency_t;

Please chose a supported frequency above that is compatible with your RFM95 (or likewise single band compatible sx1276 radio) module and change line #22 in <<SX1276GenericPingPong/GenericPingPong.cpp>> to the correct enum above.

Wiring

This program is aimed at working without modifications with RFM95W LoRa 900MHz modules in both a Breakout board and a FeatherWing version.

FeatherWing setup

This wiring diagram is useful if your RFM95W LoRa 900MHz module is a Feather wing made by Adafruit.

Before jumpers are soldered in:

/media/uploads/dev_alexander/feather_pinouts.jpg

After jumpers are soldered in:

/media/uploads/dev_alexander/rfm95_feather_pinouts_drawn_in.jpg

Note: The default pin configurations for the radio in this program (found in <<PinMap.h>> under targets MAX32630FTHR and MAX32630FTHR ) can be changed to suite additional modifications built from a fork of this program repo. If this is the case, the diagrams above will need to be changed to suite the new pin map.

For more information, a detailed wiring guide for the RFM95W Featherwing can be found here.

Breakout Board

For a breakout board, the following wiring diagram will work with both the MAX32630FTHR and the MAX32630FTHR mbed boards if wired in the same locations:

Before the RFM95W is connected with wires:

/media/uploads/dev_alexander/rfm95_breakout_pinouts.jpg

After the RFM95W is connected with wires:

/media/uploads/dev_alexander/rfm95_breakout_pinouts_drawn_in.jpg

The representations of the connections above can be found in<<PinName.h>> under targets MAX32630FTHR and MAX32630FTHR.

This default pin configuration will set you up with a connection to the MCU.

For more information, a detailed wiring guide for the RFM95W Brakout Board can be found here.

Antenna

Since this is radio communication, we are going to need antennas to be attached to both of the Radios used in this example.

For more information on how to solder an antenna to the RFM95, please click here

Committer:
Helmut64
Date:
Thu Feb 22 11:12:24 2018 +0000
Revision:
16:675f4d0ee9e9
Parent:
13:5a32a1922fbc
Child:
17:98f2528e8399
Added proper PinMap for the Heltec Board; updated libs

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Helmut64 0:c43b6919ae15 1 /*
Helmut64 0:c43b6919ae15 2 * Copyright (c) 2017 Helmut Tschemernjak
Helmut64 0:c43b6919ae15 3 * 30826 Garbsen (Hannover) Germany
Helmut64 0:c43b6919ae15 4 * Licensed under the Apache License, Version 2.0);
Helmut64 0:c43b6919ae15 5 */
Helmut64 0:c43b6919ae15 6 #include "main.h"
Helmut64 0:c43b6919ae15 7
Helmut64 8:3b0d7b4ff28f 8 /*
Helmut64 8:3b0d7b4ff28f 9 * IMPORTANT NOTE
Helmut64 8:3b0d7b4ff28f 10 * Use the Nucleo-L073RZ target for the STM B_L072Z_LRWAN1 LoRa board
Helmut64 8:3b0d7b4ff28f 11 */
Helmut64 13:5a32a1922fbc 12 DigitalOut myled(LED2);
Helmut64 0:c43b6919ae15 13 BufferedSerial *ser;
Helmut64 0:c43b6919ae15 14
Helmut64 0:c43b6919ae15 15 int main() {
Helmut64 0:c43b6919ae15 16 ser = new BufferedSerial(USBTX, USBRX);
Helmut64 16:675f4d0ee9e9 17 ser->baud(230400);
Helmut64 0:c43b6919ae15 18 ser->format(8);
Helmut64 0:c43b6919ae15 19 ser->printf("Hello World\n\r");
Helmut64 0:c43b6919ae15 20 myled = 1;
Helmut64 13:5a32a1922fbc 21
Helmut64 0:c43b6919ae15 22 SX1276PingPong();
Helmut64 0:c43b6919ae15 23 }
Helmut64 0:c43b6919ae15 24
Helmut64 0:c43b6919ae15 25
Helmut64 0:c43b6919ae15 26 void dump(const char *title, const void *data, int len, bool dwords)
Helmut64 0:c43b6919ae15 27 {
Helmut64 0:c43b6919ae15 28 dprintf("dump(\"%s\", 0x%x, %d bytes)", title, data, len);
Helmut64 0:c43b6919ae15 29
Helmut64 0:c43b6919ae15 30 int i, j, cnt;
Helmut64 0:c43b6919ae15 31 unsigned char *u;
Helmut64 0:c43b6919ae15 32 const int width = 16;
Helmut64 0:c43b6919ae15 33 const int seppos = 7;
Helmut64 0:c43b6919ae15 34
Helmut64 0:c43b6919ae15 35 cnt = 0;
Helmut64 0:c43b6919ae15 36 u = (unsigned char *)data;
Helmut64 0:c43b6919ae15 37 while (len > 0) {
Helmut64 0:c43b6919ae15 38 ser->printf("%08x: ", (unsigned int)data + cnt);
Helmut64 0:c43b6919ae15 39 if (dwords) {
Helmut64 0:c43b6919ae15 40 unsigned int *ip = ( unsigned int *)u;
Helmut64 0:c43b6919ae15 41 ser->printf(" 0x%08x\r\n", *ip);
Helmut64 0:c43b6919ae15 42 u+= 4;
Helmut64 0:c43b6919ae15 43 len -= 4;
Helmut64 0:c43b6919ae15 44 cnt += 4;
Helmut64 0:c43b6919ae15 45 continue;
Helmut64 0:c43b6919ae15 46 }
Helmut64 0:c43b6919ae15 47 cnt += width;
Helmut64 0:c43b6919ae15 48 j = len < width ? len : width;
Helmut64 0:c43b6919ae15 49 for (i = 0; i < j; i++) {
Helmut64 0:c43b6919ae15 50 ser->printf("%2.2x ", *(u + i));
Helmut64 0:c43b6919ae15 51 if (i == seppos)
Helmut64 0:c43b6919ae15 52 ser->putc(' ');
Helmut64 0:c43b6919ae15 53 }
Helmut64 0:c43b6919ae15 54 ser->putc(' ');
Helmut64 0:c43b6919ae15 55 if (j < width) {
Helmut64 0:c43b6919ae15 56 i = width - j;
Helmut64 0:c43b6919ae15 57 if (i > seppos + 1)
Helmut64 0:c43b6919ae15 58 ser->putc(' ');
Helmut64 0:c43b6919ae15 59 while (i--) {
Helmut64 0:c43b6919ae15 60 printf("%s", " ");
Helmut64 0:c43b6919ae15 61 }
Helmut64 0:c43b6919ae15 62 }
Helmut64 0:c43b6919ae15 63 for (i = 0; i < j; i++) {
Helmut64 0:c43b6919ae15 64 int c = *(u + i);
Helmut64 0:c43b6919ae15 65 if (c >= ' ' && c <= '~')
Helmut64 0:c43b6919ae15 66 ser->putc(c);
Helmut64 0:c43b6919ae15 67 else
Helmut64 0:c43b6919ae15 68 ser->putc('.');
Helmut64 0:c43b6919ae15 69 if (i == seppos)
Helmut64 0:c43b6919ae15 70 ser->putc(' ');
Helmut64 0:c43b6919ae15 71 }
Helmut64 0:c43b6919ae15 72 len -= width;
Helmut64 0:c43b6919ae15 73 u += width;
Helmut64 0:c43b6919ae15 74 ser->printf("\r\n");
Helmut64 0:c43b6919ae15 75 }
Helmut64 0:c43b6919ae15 76 ser->printf("--\r\n");
Helmut64 0:c43b6919ae15 77 }