RFM95@900MHz Feather+Aduino MEGA2560 Problem

Projects Networking, Protocols, and Devices
1

I am coding a sketch for wireless communication with Radio-Head LoRa module.
I modified the example sketch, reliable_server and client, in Aduino IDE that Adafruit recommend.
I use RFM95@900MHz feather.
Wireless communication works well with RFM95@900 and Aduino UNO combination, but "init failed" error occurs with RFM95@900 and Aduino MEGA 2560 combination.

#include <RadioHead.h>
#include <RHReliableDatagram.h>
#include <RH_RF95.h>
#include <SPI.h>

#define CLIENT_ADDRESS 1
#define SERVER_ADDRESS 2

RH_RF95 driver;
RHReliableDatagram manager(driver,CLIENT_ADDRESS);

#define Lora.setPins(53, 40, 21)// MEGA
//#define Lora.setPins(10, 9, 2)//UNO
.......
while (!Serial) ; // Wait for serial port to be available
if (!manager.init())
Serial.println("init failed");
else
Serial.println("initialization success");

2

Which module is that ? Can you provide a link ?

To what pins on the UNO and Mega have youconnected the SPI pins SCK, MOSI, MISO needed for the LoRa module ?

3

#define Lora.setPins(53, 40, 21)// MEGA, 53(Chip select), 40(reset), 21(Interrupt)
//#define Lora.setPins(10, 9, 2)//UNO, 10(Chip select),9(reset), 2(Interrupt)
// MEGA MISO(50), MOSI(51), SCK(52)
// UNO MISO(12), MOSI(11), SCK(13)

I think wiring is OK because the module do LoRa communication works well with the above wiring and other LoRa sketch.

[https://cdn-learn.adafruit.com/downloads/pdf/radio-featherwing.pdf]

4

I am confused.

You need to make clear to the forum exactly what code you have working, and what code does not.

Do the basic library examples work, both on UNO and Mega ?

What voltage level conversion circuits are you using between the UNO\Mega and the RFM95 Feather ?

5

I can't upload the code because I am new user.

The working codes both on MEGA and UNO are "rf95_client" and "rf95_server".
"rf95_reliable_datagram_client" and "rf95_reliable_datagram_server" work on UNO, but don't work on MEGA.

The codes are from Aduino's examples.

MEGA and UNO 3.3V have supply pins, so I can supply 3.3V to module. I don't need voltage level conversion from 5V to 3.3V.

#include <RadioHead.h>
#include <RHReliableDatagram.h>
#include <RH_RF95.h>
#include <SPI.h>

#define CLIENT_ADDRESS 1
#define SERVER_ADDRESS 2

RH_RF95 driver;
RHReliableDatagram manager(driver,CLIENT_ADDRESS);

#define Lora.setPins(53, 40, 21)// MEGA
//#define Lora.setPins(10, 9, 2)//UNO
.......
while (!Serial) ; // Wait for serial port to be available
if (!manager.init())
Serial.println("init failed");
else
Serial.println("initialization success");

6

Why do you think you do not ?

7

Because MEGA and UNO can supply 3.3V to module and several codes work with 3.3V from MEGA and UNO board.

8

Plain wrong.

Supplying the 3.3v logic level LoRa device with 3.3v from the UNO\Mega does not turn their 5v logic level pins into 3.3v ones.

Wire the modules correctly.

9

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.