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v3_firmware/RFM95.cpp
Stefan Brand 8c200e3309 Initial Checkin
2020-11-26 16:56:36 +01:00

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/*
RFM95.cpp - Library for RFM95 LoRa module.
Created by Leo Korbee, March 31, 2018.
Released into the public domain.
@license Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
Thanks to all the folks who contributed on the base of this code.
(Gerben den Hartog, et al - Ideetron.nl)
*/
#include "Arduino.h"
#include "RFM95.h"
#include <SPI.h>
// constructor
RFM95::RFM95(int DIO0, int NSS)
{
_DIO0 = DIO0;
_NSS = NSS;
// init tinySPI
SPI.setDataMode(SPI_MODE0);
SPI.begin();
}
/*
*****************************************************************************************
* Description: Function used to initialize the RFM module on startup
*****************************************************************************************
*/
void RFM95::init()
{
// set pinmodes input/output
pinMode(_NSS, OUTPUT);
pinMode(_DIO0, INPUT);
// Set default Datarate Config SF7BW125
_sf = 0x74;
_bw = 0x72;
_mc = 0x04;
// NSS for starting and stopping communication with the RFM95 module
digitalWrite(_NSS, HIGH);
//Switch RFM to sleep
RFM_Write(0x01,0x00);
//Set RFM in LoRa mode
RFM_Write(0x01,0x80);
//Set RFM in Standby mode wait on mode ready
RFM_Write(0x01,0x81);
/*
while (digitalRead(DIO5) == LOW)
{
}
*/
delay(10);
//Set carrair frequency
// 868.100 MHz / 61.035 Hz = 14222987 = 0xD9068B
RFM_Write(0x06,0xD9);
RFM_Write(0x07,0x06);
RFM_Write(0x08,0x8B);
// Minmal Power
//RFM_Write(0x09,0xF0);
//PA pin (maximal power)
RFM_Write(0x09,0xFF);
//BW = 125 kHz, Coding rate 4/5, Explicit header mode
RFM_Write(0x1D,0x72);
//Spreading factor 7, PayloadCRC On
RFM_Write(0x1E,0xB4);
//Rx Timeout set to 37 symbols
RFM_Write(0x1F,0x25);
//Preamble length set to 8 symbols
//0x0008 + 4 = 12
RFM_Write(0x20,0x00);
RFM_Write(0x21,0x08);
//Low datarate optimization off AGC auto on
RFM_Write(0x26,0x0C);
//Set LoRa sync word
RFM_Write(0x39,0x34);
//Set IQ to normal values
RFM_Write(0x33,0x27);
RFM_Write(0x3B,0x1D);
//Set FIFO pointers
//TX base adress
RFM_Write(0x0E,0x80);
//Rx base adress
RFM_Write(0x0F,0x00);
//Switch RFM to sleep
RFM_Write(0x01,0x00);
}
/*
*****************************************************************************************
* Description : Funtion that writes a register from the RFM
*
* Arguments : RFM_Address Address of register to be written
* RFM_Data Data to be written
*****************************************************************************************
*/
void RFM95::RFM_Write(unsigned char RFM_Address, unsigned char RFM_Data)
{
//Set NSS pin Low to start communication
digitalWrite(_NSS,LOW);
//Send Addres with MSB 1 to make it a write command
SPI.transfer(RFM_Address | 0x80);
//Send Data
SPI.transfer(RFM_Data);
//Set NSS pin High to end communication
digitalWrite(_NSS,HIGH);
}
/*
*****************************************************************************************
* Description : Funtion that reads a register from the RFM and returns the value
*
* Arguments : RFM_Address Address of register to be read
*
* Returns : Value of the register
*****************************************************************************************
*/
unsigned char RFM95::RFM_Read(unsigned char RFM_Address)
{
unsigned char RFM_Data;
//Set NSS pin low to start SPI communication
digitalWrite(_NSS,LOW);
//Send Address
SPI.transfer(RFM_Address);
//Send 0x00 to be able to receive the answer from the RFM
RFM_Data = SPI.transfer(0x00);
//Set NSS high to end communication
digitalWrite(_NSS,HIGH);
//Return received data
return RFM_Data;
}
/*
*****************************************************************************************
* Description : Set Datarate and Spreading Factor
*
* Arguments : datarate Lora Datarate Enum (see RFM95.h)
*****************************************************************************************
*/
void RFM95::RFM_Set_Datarate(lora_dr_t datarate) {
switch(datarate) {
case SF7BW125:
_sf = 0x74;
_bw = 0x72;
_mc = 0x04;
break;
case SF8BW125:
_sf = 0x84;
_bw = 0x72;
_mc = 0x04;
break;
case SF9BW125:
_sf = 0x94;
_bw = 0x72;
_mc = 0x04;
break;
case SF10BW125:
_sf = 0xA4;
_bw = 0x72;
_mc = 0x04;
break;
case SF11BW125:
_sf = 0xB4;
_bw = 0x72;
_mc = 0x0C;
break;
case SF12BW125:
_sf = 0xC4;
_bw = 0x72;
_mc = 0x0C;
break;
default:
_sf = 0x74;
_bw = 0x72;
_mc = 0x04;
break;
}
}
/*
*****************************************************************************************
* Description : Function for sending a package with the RFM
*
* Arguments : *RFM_Tx_Package Pointer to arry with data to be send
* Package_Length Length of the package to send
*****************************************************************************************
*/
void RFM95::RFM_Send_Package(unsigned char *RFM_Tx_Package, unsigned char Package_Length)
{
unsigned char i;
// unsigned char RFM_Tx_Location = 0x00;
//Set RFM in Standby mode wait on mode ready
RFM_Write(0x01,0x81);
/*
while (digitalRead(DIO5) == LOW)
{
}
*/
delay(10);
//Switch DIO0 to TxDone
//RFM_Write(0x40,0x40);
//Set carrier frequency
/*
fixed frequency
// 868.100 MHz / 61.035 Hz = 14222987 = 0xD9068B
_rfm95.RFM_Write(0x06,0xD9);
_rfm95.RFM_Write(0x07,0x06);
_rfm95.RFM_Write(0x08,0x8B);
*/
//Channel 0 868.100 MHz / 61.035 Hz = 14222987 = 0xD9068B
RFM_Write(0x06,0xD9);
RFM_Write(0x07,0x06);
RFM_Write(0x08,0x8B);
// EU863-870 specifications
/*
// TCNT0 is timer0 continous timer, kind of random selection of frequency
switch (TCNT0 % 8)
{
case 0x00: //Channel 0 868.100 MHz / 61.035 Hz = 14222987 = 0xD9068B
RFM_Write(0x06,0xD9);
RFM_Write(0x07,0x06);
RFM_Write(0x08,0x8B);
break;
case 0x01: //Channel 1 868.300 MHz / 61.035 Hz = 14226264 = 0xD91358
RFM_Write(0x06,0xD9);
RFM_Write(0x07,0x13);
RFM_Write(0x08,0x58);
break;
case 0x02: //Channel 2 868.500 MHz / 61.035 Hz = 14229540 = 0xD92024
RFM_Write(0x06,0xD9);
RFM_Write(0x07,0x20);
RFM_Write(0x08,0x24);
break;
// added five more channels
case 0x03: // Channel 3 867.100 MHz / 61.035 Hz = 14206603 = 0xD8C68B
RFM_Write(0x06,0xD8);
RFM_Write(0x07,0xC6);
RFM_Write(0x08,0x8B);
break;
case 0x04: // Channel 4 867.300 MHz / 61.035 Hz = 14209880 = 0xD8D358
RFM_Write(0x06,0xD8);
RFM_Write(0x07,0xD3);
RFM_Write(0x08,0x58);
break;
case 0x05: // Channel 5 867.500 MHz / 61.035 Hz = 14213156 = 0xD8E024
RFM_Write(0x06,0xD8);
RFM_Write(0x07,0xE0);
RFM_Write(0x08,0x24);
break;
case 0x06: // Channel 6 867.700 MHz / 61.035 Hz = 14216433 = 0xD8ECF1
RFM_Write(0x06,0xD8);
RFM_Write(0x07,0xEC);
RFM_Write(0x08,0xF1);
break;
case 0x07: // Channel 7 867.900 MHz / 61.035 Hz = 14219710 = 0xD8F9BE
RFM_Write(0x06,0xD8);
RFM_Write(0x07,0xF9);
RFM_Write(0x08,0xBE);
break;
// FSK 868.800 Mhz => not used in this config
// 869.525 - SF9BW125 (RX2 downlink only) for package received
}
*/
//SF7 BW 125 kHz
RFM_Write(0x1E,_sf); //SF7 CRC On
RFM_Write(0x1D,_bw); //125 kHz 4/5 coding rate explicit header mode
RFM_Write(0x26,_mc); //Low datarate optimization off AGC auto on
//Set IQ to normal values
RFM_Write(0x33,0x27);
RFM_Write(0x3B,0x1D);
//Set payload length to the right length
RFM_Write(0x22,Package_Length);
//Get location of Tx part of FiFo
//RFM_Tx_Location = RFM_Read(0x0E);
//Set SPI pointer to start of Tx part in FiFo
//RFM_Write(0x0D,RFM_Tx_Location);
RFM_Write(0x0D,0x80); // hardcoded fifo location according RFM95 specs
//Write Payload to FiFo
for (i = 0;i < Package_Length; i++)
{
RFM_Write(0x00,*RFM_Tx_Package);
RFM_Tx_Package++;
}
//Switch RFM to Tx
RFM_Write(0x01,0x83);
//Wait for TxDone
//while( digitalRead(_DIO0) == LOW )
//{
//}
while((RFM_Read(0x12) & 0x08) != 0x08)
{
}
//Clear interrupt
RFM_Write(0x12,0x08);
//Switch RFM to sleep
RFM_Write(0x01,0x00);
}
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