Receive Basic: Rasmatic/RFM69-Arduino-Library
Next step was to extend my code to receive packets (no addressing or encryption). Initially I didn’t receive any messages as I had neglected to configure the variable length flag (RegPacketConfig bit 7) and had a typo in the RegRxBw register configuration.
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namespace devMobile.IoT.Rfm69Hcw.ReceiveBasic
{
using System;
using System.Diagnostics;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Text;
using System.Threading.Tasks;
using Windows.ApplicationModel.Background;
using Windows.Devices.Spi;
using Windows.Devices.Gpio;
public sealed class Rfm69HcwDevice
{
private SpiDevice Rfm69Hcw;
private const byte RegisterAddressReadMask = 0X7f;
private const byte RegisterAddressWriteMask = 0x80;
public Rfm69HcwDevice(int chipSelectPin, int resetPin)
{
SpiController spiController = SpiController.GetDefaultAsync().AsTask().GetAwaiter().GetResult();
var settings = new SpiConnectionSettings(chipSelectPin)
{
ClockFrequency = 500000,
Mode = SpiMode.Mode0,
};
// Factory reset pin configuration
GpioController gpioController = GpioController.GetDefault();
GpioPin resetGpioPin = gpioController.OpenPin(resetPin);
resetGpioPin.SetDriveMode(GpioPinDriveMode.Output);
resetGpioPin.Write(GpioPinValue.Low);
Task.Delay(100);
resetGpioPin.Write(GpioPinValue.High);
Task.Delay(100);
resetGpioPin.Write(GpioPinValue.Low);
Task.Delay(100);
Rfm69Hcw = spiController.GetDevice(settings);
}
public Byte RegisterReadByte(byte address)
{
byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
byte[] readBuffer = new byte[1];
Debug.Assert(Rfm69Hcw != null);
Rfm69Hcw.TransferSequential(writeBuffer, readBuffer);
return readBuffer[0];
}
public ushort RegisterReadWord(byte address)
{
byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
byte[] readBuffer = new byte[2];
Debug.Assert(Rfm69Hcw != null);
Rfm69Hcw.TransferSequential(writeBuffer, readBuffer);
return (ushort)(readBuffer[1] + (readBuffer[0] << 8));
}
public byte[] RegisterRead(byte address, int length)
{
byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
byte[] readBuffer = new byte[length];
Debug.Assert(Rfm69Hcw != null);
Rfm69Hcw.TransferSequential(writeBuffer, readBuffer);
return readBuffer;
}
public void RegisterWriteByte(byte address, byte value)
{
byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, value };
Debug.Assert(Rfm69Hcw != null);
Rfm69Hcw.Write(writeBuffer);
}
public void RegisterWriteWord(byte address, ushort value)
{
byte[] valueBytes = BitConverter.GetBytes(value);
byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, valueBytes[0], valueBytes[1] };
Debug.Assert(Rfm69Hcw != null);
Rfm69Hcw.Write(writeBuffer);
}
public void RegisterWrite(byte address, [ReadOnlyArray()] byte[] bytes)
{
byte[] writeBuffer = new byte[1 + bytes.Length];
Debug.Assert(Rfm69Hcw != null);
Array.Copy(bytes, 0, writeBuffer, 1, bytes.Length);
writeBuffer[0] = address |= RegisterAddressWriteMask;
Rfm69Hcw.Write(writeBuffer);
}
public void RegisterDump()
{
Debug.WriteLine("Register dump");
for (byte registerIndex = 0; registerIndex <= 0x3D; registerIndex++)
{
byte registerValue = this.RegisterReadByte(registerIndex);
Debug.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", registerIndex, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));
}
}
}
public sealed class StartupTask : IBackgroundTask
{
private const int ChipSelectLine = 1;
private const int ResetLine = 25;
private Rfm69HcwDevice rfm69Device = new Rfm69HcwDevice(ChipSelectLine, ResetLine);
const double RH_RF6M9HCW_FXOSC = 32000000.0;
const double RH_RFM69HCW_FSTEP = RH_RF6M9HCW_FXOSC / 524288.0;
public void Run(IBackgroundTaskInstance taskInstance)
{
//rfm69Device.RegisterDump();
// regOpMode standby
rfm69Device.RegisterWriteByte(0x01, 0b00000100);
// BitRate MSB/LSB
rfm69Device.RegisterWriteByte(0x03, 0x34);
rfm69Device.RegisterWriteByte(0x04, 0x00);
// Calculate the frequency accoring to the datasheett
byte[] bytes = BitConverter.GetBytes((uint)(915000000.0 / RH_RFM69HCW_FSTEP));
Debug.WriteLine("Byte Hex 0x{0:x2} 0x{1:x2} 0x{2:x2} 0x{3:x2}", bytes[0], bytes[1], bytes[2], bytes[3]);
rfm69Device.RegisterWriteByte(0x07, bytes[2]);
rfm69Device.RegisterWriteByte(0x08, bytes[1]);
rfm69Device.RegisterWriteByte(0x09, bytes[0]);
// RegRxBW
rfm69Device.RegisterWriteByte(0x19, 0x2a);
// Setup preamble length to 16 (default is 3) RegPreambleMsb RegPreambleLsb
rfm69Device.RegisterWriteByte(0x2C, 0x0);
rfm69Device.RegisterWriteByte(0x2D, 0x10);
// RegSyncConfig Set the Sync length and byte values SyncOn + 3 custom sync bytes
rfm69Device.RegisterWriteByte(0x2e, 0x90);
// RegSyncValues1 thru RegSyncValues3
rfm69Device.RegisterWriteByte(0x2f, 0xAA);
rfm69Device.RegisterWriteByte(0x30, 0x2D);
rfm69Device.RegisterWriteByte(0x31, 0xD4);
// RegPacketConfig1 Variable length with CRC on
rfm69Device.RegisterWriteByte(0x37, 0x90);
rfm69Device.RegisterWriteByte(0x01, 0b00010000); // RegOpMode set ReceiveMode
rfm69Device.RegisterDump();
while (true)
{
// Wait until a packet is received, no timeouts in PoC
Debug.WriteLine("Receive-Wait");
byte IrqFlags = rfm69Device.RegisterReadByte(0x28); // RegIrqFlags2
while ((IrqFlags & 0b00000100) == 0) // wait until PayLoadReady set
{
Task.Delay(20).Wait();
IrqFlags = rfm69Device.RegisterReadByte(0x28); // RegIrqFlags2
//Debug.WriteLine(string.Format("RegIrqFlags {0}", Convert.ToString((byte)IrqFlags, 2).PadLeft(8, '0')));
Debug.Write(".");
}
Debug.WriteLine("");
// Rwad the length
byte numberOfBytes = rfm69Device.RegisterReadByte(0x0);
// Allocate buffer for message
byte[] messageBytes = new byte[numberOfBytes];
for (int i = 0; i < numberOfBytes; i++)
{
messageBytes[i] = rfm69Device.RegisterReadByte(0x00); // RegFifo
}
string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
Debug.WriteLine("Received {0} byte message {1}", messageBytes.Length, messageText);
Debug.WriteLine("Receive-Done");
}
}
}
}
I modified the Arduino application to transmit a message (with a counter so I could spot dropped messages) every second
#include <SPI.h>
#include <stdio.h>
#include <RMRFM69.h>
#define SENDER_DETECT_PIN 4
RMRFM69 radio(SPI, 10, 2, 9);
byte counter = 0 ;
void setup()
{
Serial.begin(9600);
pinMode(SENDER_DETECT_PIN, INPUT_PULLUP);
radio.Modulation = FSK;
radio.COB = RFM69;
radio.Frequency = 915000;
radio.OutputPower = 10+18; //10dBm OutputPower
radio.PreambleLength = 16; //16Byte preamble
radio.FixedPktLength = false; //packet in message which need to be send
radio.CrcDisable = false; //CRC On
radio.AesOn = false;
radio.SymbolTime = 416000; //2.4Kbps
radio.Devation = 35; //35KHz for devation
radio.BandWidth = 100; //100KHz for bandwidth
radio.SyncLength = 3; //
radio.SyncWord[0] = 0xAA;
radio.SyncWord[1] = 0x2D;
radio.SyncWord[2] = 0xD4;
radio.vInitialize();
if (digitalRead(SENDER_DETECT_PIN) == LOW)
{
Serial.println("RX start");
radio.vGoRx();
}
else
{
Serial.println("TX start");
//radio.vGoTx();
}
radio.dumpRegisters(Serial);
}
void loop()
{
char messageIn[128] = {""};
char messageOut[32]= {"Hello world:"};
if (digitalRead(SENDER_DETECT_PIN) == LOW)
{
if(radio.bGetMessage(messageIn)!=0)
{
Serial.print("MessageIn:");
Serial.println(messageIn);
}
}
else
{
Serial.print("MessageOut:") ;
itoa(counter,&messageOut[strlen( messageOut)],10);
Serial.println(messageOut);
if (!radio.bSendMessage(messageOut, strlen(messageOut)))
{
Serial.println("bSendMessage failed");
}
counter++;
delay(1000);
}
}
With the Arduino device transmitting the debug output in Visual Studio looked like this. It does seem a bit odd that the “Receive-Wait” is slowly getting longer.
Register dump
Register 0x00 - Value 0X00 - Bits 00000000
Register 0x01 - Value 0X10 - Bits 00010000
…
Register 0x3c - Value 0X0f - Bits 00001111
Register 0x3d - Value 0X02 - Bits 00000010
Receive-Wait
The thread 0x990 has exited with code 0 (0x0).
Received 13 byte message Hello world:0
Receive-Done
Receive-Wait
.............................................
Received 13 byte message Hello world:1
Receive-Done
Receive-Wait
...........................................
Received 13 byte message Hello world:2
Receive-Done
Receive-Wait
............................................
Received 13 byte message Hello world:3
Receive-Done
Receive-Wait
............................................
Received 13 byte message Hello world:4
Receive-Done
Receive-Wait
.............................................
Received 13 byte message Hello world:5
Receive-Done
Receive-Wait
............................................
Received 13 byte message Hello world:6
Receive-Done
Receive-Wait
............................................
I ran the client for several hours and it didn’t appear to drop any messages. Next step is to covert the receive and transmit code to use interrupts.
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