RFM69 hat library h WWWWWWWWoo

Again, while doing some stress testing I noticed an odd message go past in the Visual Studio output window. I had multiple devices sending addressed messages (both individual and broadcast) to the Adafruit RFM69 HCW Radio Bonnet, on my Windows 10 IoT Core device while it was sending a message every 5 seconds.

Received From 102 a 15 byte message Hello World:161
23:42:33.343 RegIrqFlags2 01100110
23:42:33.356 RegIrqFlags1 11011001
23:42:33.374 Address 0X99 10011001
Received From 153 a 15 byte message Hello World:106
23:42:33.761 RegIrqFlags2 01100110
23:42:33.774 RegIrqFlags1 11011001
23:42:33.791 Address 0X66 01100110
Received From 102 a 15 byte message Hello World:162
The thread 0xd20 has exited with code 0 (0x0).
23:42:34.500 RegIrqFlags2 01100110
23:42:34.501 Send-hello world 11:42:34 PM
23:42:34.520 RegIrqFlags1 11011001
23:42:34.545 Send-Done
23:42:34.551 Address 0X10 00010000
Received From 16 a 15 byte message h    WWWWWWWWoo
23:42:34.686 RegIrqFlags2 00001000
23:42:34.701 RegIrqFlags1 10110000
23:42:34.715 Transmit-Done
Transmit-Done
23:42:34.902 RegIrqFlags2 01100110
23:42:34.915 RegIrqFlags1 11011001
23:42:34.931 Address 0X66 01100110
Received From 102 a 15 byte message Hello World:163
23:42:35.626 RegIrqFlags2 01100110
23:42:35.640 RegIrqFlags1 11011001
23:42:35.659 Address 0X99 10011001
Received From 153 a 15 byte message Hello World:108
23:42:36.042 RegIrqFlags2 01100110
23:42:36.055 RegIrqFlags1 11011001
23:42:36.073 Address 0X66 01100110

The RegIrqFlags2 CrcOk (bit 1) was set and the message was corrupt.

RegIrqFlags2 bit flags from SX1231 datasheet

I have added code to check the CRC on inbound messages if this functionality is enabled. So the library can be used with CRCs disabled I have added a flag to the OnDataReceivedEventArgs class to indicate whether the CRC on the inbound message was OK.

private readonly Object Rfm9XRegFifoLock = new object();
...
private void ProcessPayloadReady(RegIrqFlags1 irqFlags1, RegIrqFlags2 irqFlags2)
{
	byte? address = null;
	byte numberOfBytes;
	byte[] messageBytes;

	lock (Rfm9XRegFifoLock)
	{
		// Read the length of the buffer if variable length packets
		if (PacketFormat == RegPacketConfig1PacketFormat.VariableLength)
		{
			numberOfBytes = RegisterManager.ReadByte((byte)Rfm69HcwDevice.Registers.RegFifo);
		}
		else
		{
			numberOfBytes = PayloadLength;
		}

		// Remove the address from start of the payload
		if (AddressingEnabled)
		{
			address = RegisterManager.ReadByte((byte)Rfm69HcwDevice.Registers.RegFifo);

			Debug.WriteLine("{0:HH:mm:ss.fff} Address 0X{1:X2} {2}", DateTime.Now, address, Convert.ToString((byte)address, 2).PadLeft(8, '0'));
			numberOfBytes--;
		}

		// Allocate a buffer for the payload and read characters from the Fifo
		messageBytes = new byte[numberOfBytes];

		for (int i = 0; i < numberOfBytes; i++)
		{
			messageBytes[i] = RegisterManager.ReadByte((byte)Rfm69HcwDevice.Registers.RegFifo);
		}
	}
...
public void SendMessage(byte[] messageBytes)
{
#region Guard conditions
#endregion

	lock (Rfm9XRegFifoLock)
	{
		SetMode(RegOpModeMode.StandBy);

		if (PacketFormat == RegPacketConfig1PacketFormat.VariableLength)
		{
			RegisterManager.WriteByte((byte)Registers.RegFifo, (byte)messageBytes.Length);
		}

		foreach (byte b in messageBytes)
		{
			this.RegisterManager.WriteByte((byte)Registers.RegFifo, b);
		}

		SetMode(RegOpModeMode.Transmit);
	}
}

I can most probably reduce the duration which I hold the lock for but that will require some more stress testing.

RFM69 hat library Hello Woooooooo

While doing some stress testing I noticed an odd message go past in the Visual Studio output window. I had multiple devices sending addressed messages (both individual and broadcast) to the Adafruit RFM69 HCW Radio Bonnet, on my Windows 10 IoT Core device while it was sending a message every 5 seconds.

Received From 153 a 13 byte message Hello World:7
18:43:56.544 RegIrqFlags2 01100110
18:43:56.558 RegIrqFlags1 11011001
18:43:56.575 Address 0X66 01100110
Received From 102 a 15 byte message Hello World:162
The thread 0x254 has exited with code 0 (0x0).
18:43:57.699 Send-hello world 6:43:57 PM
18:43:57.699 RegIrqFlags2 01100110
18:43:57.731 RegIrqFlags1 10000000
18:43:57.747 Address 0X66 01100110
18:43:57.765 Send-Done
Received From 102 a 15 byte message Hello Woooooooo
18:43:57.987 RegIrqFlags2 00001000
18:43:58.003 RegIrqFlags1 10110000
18:43:58.017 Transmit-Done
Transmit-Done
18:43:58.825 RegIrqFlags2 01100110
18:43:58.838 RegIrqFlags1 11011001
18:43:58.857 Address 0X66 01100110
Received From 102 a 15 byte message Hello World:164
18:43:59.966 RegIrqFlags2 01100110
18:43:59.979 RegIrqFlags1 11011001
18:43:59.998 Address 0X66 01100110

The odd thing was that the RegIrqFlags2 CrcOk (bit 1) was set but the message was still corrupt.

RegIrqFlags2 bit flags from SX1231 datasheet

After looking at the code I think the problem was the reading of the received message bytes from the device FIFO and the writing of bytes of message to be transmitted into the device FIFO overlapped. To stop this occurring again I have added code to synchronise access (using a Lock) to the FIFO.

private readonly Object Rfm9XRegFifoLock = new object();
...
private void ProcessPayloadReady(RegIrqFlags1 irqFlags1, RegIrqFlags2 irqFlags2)
{
	byte? address = null;
	byte numberOfBytes;
	byte[] messageBytes;

	lock (Rfm9XRegFifoLock)
	{
		// Read the length of the buffer if variable length packets
		if (PacketFormat == RegPacketConfig1PacketFormat.VariableLength)
		{
			numberOfBytes = RegisterManager.ReadByte((byte)Rfm69HcwDevice.Registers.RegFifo);
		}
		else
		{
			numberOfBytes = PayloadLength;
		}

		// Remove the address from start of the payload
		if (AddressingEnabled)
		{
			address = RegisterManager.ReadByte((byte)Rfm69HcwDevice.Registers.RegFifo);

			Debug.WriteLine("{0:HH:mm:ss.fff} Address 0X{1:X2} {2}", DateTime.Now, address, Convert.ToString((byte)address, 2).PadLeft(8, '0'));
			numberOfBytes--;
		}

		// Allocate a buffer for the payload and read characters from the Fifo
		messageBytes = new byte[numberOfBytes];

		for (int i = 0; i < numberOfBytes; i++)
		{
			messageBytes[i] = RegisterManager.ReadByte((byte)Rfm69HcwDevice.Registers.RegFifo);
		}
	}
...
public void SendMessage(byte[] messageBytes)
{
#region Guard conditions
#endregion

	lock (Rfm9XRegFifoLock)
	{
		SetMode(RegOpModeMode.StandBy);

		if (PacketFormat == RegPacketConfig1PacketFormat.VariableLength)
		{
			RegisterManager.WriteByte((byte)Registers.RegFifo, (byte)messageBytes.Length);
		}

		foreach (byte b in messageBytes)
		{
			this.RegisterManager.WriteByte((byte)Registers.RegFifo, b);
		}

		SetMode(RegOpModeMode.Transmit);
	}
}

The code has been running for a day without any corrupted messages so the lock appears to be working. I can most probably reduce the duration which I hold the lock for but that will require some more stress testing.

RFM69 hat library Part12E

Enums and Masks – RegDIOMapping1 & RegDIOMapping2

The RFM69CW/RFM69HCW module (based on the Semtech SX1231/SX1231H) has configurable digital outputs (RegDIOMapping1 & RegDIOMapping2) . Which I use to trigger interrupts on my Windows 10 IoT Core or Arduino devices. Currently (Sep 2019) the library only supports the mapping of the digital outputs D0 & D1 when the RFM69 is in Packet Mode.

RegiDIOMapping0 & RegDIOMapping2 settings for DIO thru DIO5

I added some additional constants and enumerations for the other settings configured in RegDioMapping1 & RegDioMapping2.

// RegDioMapping1 & RegDioMapping2 Packet Mode Table 22 pg48
// DIO 0 Bits 7&6 of RegDioMapping1
[Flags]
public enum Dio0Mapping
{
	// Sleep
	// Standby
	// Frequency Synthesis
	// Reserved 00-10
	FrequencySynthesisPllLock = 0b11000000,
	ReceiveCrcOk = 0b00000000,
	ReceivePayloadReady = 0b01000000,
	ReceiveSyncAddress = 0b10000000,
	ReceiveRssi = 0b11000000,
	TransmitPacketSent = 0b00000000,
	TransmitTxReady = 0b01000000,
	// Reserved 10
	PllLock = 0b11000000
}
const Dio0Mapping Dio0MappingDefault = 0x00;

// DIO 1 Bits 5&4 of RegDioMapping1
public enum Dio1Mapping
{
	SleepFifoLevel = 0b00000000,
	SleepFifoFull = 0b00010000,
	SleepFifoNotEmpty = 0b00100000,
	// Reserved 11
	StandByFifoLevel = 0b00000000,
	StandByFifoFull = 0b00010000,
	StandByFifoNotEmpty = 0b00100000,
	FrequencySynthesisFifoLevel = 0b00000000,
	FrequencySynthesisFifoFull = 0b00010000,
	FrequencySynthesisFifoNotEmpty = 0b00100000,
	FrequencySynthesisPllLock = 0b00110000,
	ReceiveFifoLevel = 0b00000000,
	ReceiveFifoFull = 0b00010000,
	ReceiveFifoNotEmpty = 0b00100000,
	ReceiveTimeout = 0b00110000,
	TransmitFifoLevel = 0b00000000,
	TransmitFifoFull = 0b00010000,
	TransmitFifoNotEmpty = 0b00100000,
	TransmitPllLock = 0b00110000,
}
const Dio1Mapping Dio1MappingDefault = 0x00;

// DIO 2 Bits 3&2 of RegDioMapping1
public enum Dio2Mapping
{
}
const Dio2Mapping Dio2MappingDefault = 0x00;

// DIO 2 Bits 1&0 of RegDioMapping1
public enum Dio3Mapping
{
}
const Dio3Mapping Dio3MappingDefault = 0x00;

// DIO 2 Bits 7&6 of RegDioMapping2
public enum Dio4Mapping
{
}
const Dio4Mapping Dio4MappingDefault = 0x00;

// DIO 2 Bits 5&4 of RegDioMapping2
public enum Dio5Mapping
{
}
const Dio5Mapping Dio5MappingDefault = 0x00;

// RegDioMapping2 Bits 2-0
public enum ClockOutDioMapping : byte
{
	FXOsc = 0b00000000,
	FXOscDiv2 = 0b00000001,
	FXOscDiv4 = 0b00000010,
	FXOscDiv8 = 0b00000011,
	FXOscDiv16 = 0b00000100,
	FXOscDiv32 = 0b00000101,
	RC = 0b00000110,
	Off = 0b00000111,
}
public const ClockOutDioMapping ClockOutDioMappingDefault = ClockOutDioMapping.Off;

I also added some code to the initialise method to set the RegDioMapping1 & RegDioMapping1 only if the values were not the defaults.

public void Initialise(RegOpModeMode modeAfterInitialise,
	bool sequencer = RegOpModeSequencerDefault,
	bool listen = RegOpModeListenDefault,
	BitRate bitRate = BitRateDefault,
	ushort frequencyDeviation = frequencyDeviationDefault,
	double frequency = FrequencyDefault,
	AfcLowBeta afcLowBeta = AfcLowBetaDefault,
	ListenModeIdleResolution listenModeIdleResolution = ListenModeIdleResolutionDefault, ListenModeRXTime listenModeRXTime = ListenModeRXTimeDefault, ListenModeCriteria listenModeCrieria = ListenModeCriteriaDefault, ListenModeEnd listenModeEnd = ListenModeEndDefault,
	byte listenCoefficientIdle = ListenCoefficientIdleDefault,
	byte listenCoefficientReceive = ListenCoefficientReceiveDefault,
	bool pa0On = pa0OnDefault, bool pa1On = pa1OnDefaut, bool pa2On = pa2OnDefault, byte outputpower = OutputpowerDefault,
	PaRamp paRamp = PaRampDefault,
	bool ocpOn = OcpOnDefault, byte ocpTrim = OcpTrimDefault,
	LnaZin lnaZin = LnaZinDefault, LnaCurrentGain lnaCurrentGain = LnaCurrentGainDefault, LnaGainSelect lnaGainSelect = LnaGainSelectDefault,
	byte dccFrequency = DccFrequencyDefault, RxBwMant rxBwMant = RxBwMantDefault, byte RxBwExp = RxBwExpDefault,
	byte dccFreqAfc = DccFreqAfcDefault, byte rxBwMantAfc = RxBwMantAfcDefault, byte bxBwExpAfc = RxBwExpAfcDefault,
	Dio0Mapping dio0Mapping = Dio0MappingDefault,
	Dio1Mapping dio1Mapping = Dio1MappingDefault,
	Dio2Mapping dio2Mapping = Dio2MappingDefault,
	Dio3Mapping dio3Mapping = Dio3MappingDefault,
	Dio4Mapping dio4Mapping = Dio4MappingDefault,
	Dio5Mapping dio5Mapping = Dio5MappingDefault,
	ClockOutDioMapping clockOutDioMapping = ClockOutDioMappingDefault,
	ushort preambleSize = PreambleSizeDefault,
	RegSyncConfigFifoFileCondition? syncFifoFileCondition = null, byte? syncTolerance = null, byte[] syncValues = null,
	RegPacketConfig1PacketFormat packetFormat = RegPacketConfig1PacketFormat.FixedLength,
	RegPacketConfig1DcFree packetDcFree = RegPacketConfig1DcFreeDefault,
	bool packetCrc = PacketCrcOnDefault,
	bool packetCrcAutoClear = PacketCrcAutoClearDefault,
	byte payloadLength = PayloadLengthDefault,
	byte? addressNode = null, byte? addressbroadcast = null,
	TxStartCondition txStartCondition = TxStartConditionDefault, byte fifoThreshold = FifoThresholdDefault,
	byte interPacketRxDelay = InterPacketRxDelayDefault, bool autoRestartRx = AutoRestartRxDefault,
	byte[] aesKey = null
	)
...
	// RegDioMapping1
	if ((dio0Mapping != Dio0MappingDefault) ||
	    (dio1Mapping != Dio1MappingDefault) ||
	    (dio2Mapping != Dio2MappingDefault) ||
	    (dio3Mapping != Dio3MappingDefault))
	{
		byte regDioMapping1Value = (byte)dio0Mapping;

		regDioMapping1Value |= (byte)dio1Mapping;
		regDioMapping1Value |= (byte)dio2Mapping;
		regDioMapping1Value |= (byte)dio3Mapping;

		RegisterManager.WriteByte((byte)Registers.RegDioMapping1, regDioMapping1Value);
	}

	// RegDioMapping2
	if ((dio4Mapping != Dio4MappingDefault) ||
		 (dio5Mapping != Dio5MappingDefault) ||
		 (clockOutDioMapping != ClockOutDioMappingDefault ))
	{
		byte regDioMapping2Value = (byte)dio4Mapping;

		regDioMapping2Value |= (byte)dio5Mapping;
		regDioMapping2Value |= (byte)clockOutDioMapping;

		RegisterManager.WriteByte((byte)Registers.RegDioMapping2, regDioMapping2Value);
	}

I had several failed attempts at defining suitable enumerations for configuring the RegDioMapping1 & RegDioMapping2 registers. I initially started with an enumeration for each Mode (Sleep, StandBy etc.) but the implementation was quite complex. The initial version only supports DIO0 & DIO1 as most of the shields I have, only DIO0 adn/or DIO1 are connected.

RFM69 hat library Part12D

Enums and Masks – Packet lengths, addressing & CRCs

The RFM69CW/RFM69HCW module (based on the Semtech SX1231/SX1231H) has configurable (RegSyncConfig) synchronisation sequences (the length, tolerance for errors and the individual byte values).

By default synchronisation is enabled and a default sequence of bytes is used, in my library synchronisation is NOT enabled until a SyncValue is provided.

I added some additional constants and enumerations for the other settings configured in RegSyncConfig.

// RegSyncConfig 
// This is private because default ignored and flag set based on SyncValues parameter being specified rather than default
private enum RegSyncConfigSyncOn
{
	Off = 0b00000000,
	On = 0b10000000
}

public enum RegSyncConfigFifoFileCondition
{
	SyncAddressInterrupt = 0b00000000,
	FifoFillCondition =    0b01000000
}

private const RegSyncConfigFifoFileCondition SyncFifoFileConditionDefault = RegSyncConfigFifoFileCondition.SyncAddressInterrupt;
readonly byte[] SyncValuesDefault = {0x01, 0x01, 0x01, 0x01};
public const byte SyncValuesSizeDefault = 4;
public const byte SyncValuesSizeMinimum = 1;
public const byte SyncValuesSizeMaximum = 8;

private const byte SyncToleranceDefault = 0;
public const byte SyncToleranceMinimum = 0;
public const byte SyncToleranceMaximum = 7;

I also added some guard conditions to the initialise method which validate the syncFifoFileCondition, syncTolerance and syncValues length.

public void Initialise(RegOpModeMode modeAfterInitialise,
	BitRate bitRate = BitRateDefault,
	ushort frequencyDeviation = frequencyDeviationDefault,
	double frequency = FrequencyDefault,
	ListenModeIdleResolution listenModeIdleResolution = ListenModeIdleResolutionDefault, ListenModeRXTime listenModeRXTime = ListenModeRXTimeDefault, ListenModeCrieria listenModeCrieria = ListenModeCrieriaDefault, ListenModeEnd listenModeEnd = ListenModeEndDefault,
	byte listenCoefficientIdle = ListenCoefficientIdleDefault,
	byte listenCoefficientReceive = ListenCoefficientReceiveDefault,
	bool pa0On = pa0OnDefault, bool pa1On = pa1OnDefaut, bool pa2On = pa2OnDefault, byte outputpower = OutputpowerDefault,
	PaRamp paRamp = PaRampDefault,
	bool ocpOn = OcpOnDefault, byte ocpTrim = OcpTrimDefault,
	LnaZin lnaZin = LnaZinDefault, LnaCurrentGain lnaCurrentGain = LnaCurrentGainDefault, LnaGainSelect lnaGainSelect = LnaGainSelectDefault,
	byte dccFrequency = DccFrequencyDefault, RxBwMant rxBwMant = RxBwMantDefault, byte RxBwExp = RxBwExpDefault,
	byte dccFreqAfc = DccFreqAfcDefault, byte rxBwMantAfc = RxBwMantAfcDefault, byte bxBwExpAfc = RxBwExpAfcDefault,
	ushort preambleSize = PreambleSizeDefault,
	RegSyncConfigFifoFileCondition? syncFifoFileCondition = null, byte? syncTolerance = null, byte[] syncValues = null,
	RegPacketConfig1PacketFormat packetFormat = RegPacketConfig1PacketFormat.FixedLength,
	RegPacketConfig1DcFree packetDcFree = RegPacketConfig1DcFreeDefault,
	bool packetCrc = PacketCrcOnDefault,
	bool packetCrcAutoClearOff = PacketCrcAutoClearOffDefault,
	RegPacketConfig1CrcAddressFiltering packetAddressFiltering = PacketAddressFilteringDefault,
	byte payloadLength = PayloadLengthDefault,
	byte addressNode = NodeAddressDefault, byte addressbroadcast = BroadcastAddressDefault,
	TxStartCondition txStartCondition = TxStartConditionDefault, byte fifoThreshold = FifoThresholdDefault,
	byte interPacketRxDelay = InterPacketRxDelayDefault, bool restartRx = RestartRxDefault, bool autoRestartRx = AutoRestartRxDefault,
	byte[] aesKey = null
	)
{
	RegOpModeModeCurrent = modeAfterInitialise;
	PacketFormat = packetFormat;

	#region RegSyncConfig + RegSyncValue1 to RegSyncValue8 guard conditions
	if (syncValues != null)
	{
		// If sync enabled (i.e. SyncValues array provided) check that SyncValues not to short/long and SyncTolerance not to small/big
		if ((syncValues.Length < SyncValuesSizeMinimum) || (syncValues.Length &gt; SyncValuesSizeMaximum))
		{
			throw new ArgumentException($"The syncValues array length must be between {SyncValuesSizeMinimum} and {SyncValuesSizeMaximum} bytes", "syncValues");
		}
		if (syncTolerance.HasValue)
		{
			if ((syncTolerance < SyncToleranceMinimum) || (syncTolerance &gt; SyncToleranceMaximum))
			{
				throw new ArgumentException($"The syncTolerance size must be between {SyncToleranceMinimum} and {SyncToleranceMaximum}", "syncTolerance");
			}
		}
	}
	else
	{
		// If sync not enabled (i.e. SyncValues array null) check that no syncFifoFileCondition or syncTolerance configuration specified
		if (syncFifoFileCondition.HasValue)
		{
			throw new ArgumentException($"If Sync not enabled syncFifoFileCondition is not supported", "syncFifoFileCondition");
		}

		if (syncTolerance.HasValue)
		{
			throw new ArgumentException($"If Sync not enabled SyncTolerance is not supported", "syncTolerance");
		}
	}
	#endregion

I also ensure that the syncFifoFileCondition and syncTolerance are not specified if synchronisation is not enabled.

The library also supports the built in RFRM69 node and broadcast addressing which is enabled when the AddressNode and/or AddressBroadcast parameters of the Initialise method are set.

RegPacketConfig1 address filtering options

My first attempt at getting encryption and addressing working together failed badly, the Windows 10 IoT Core device didn’t receive any addressed messages when encryption was enabled. So, I went back and re-read the datasheet again and noticed

“If the address filtering is expected then AddressFiltering must be enabled on the transmitter side as well to prevent address byte to be encrypted”(Sic).

The Arduino client code had to be modified so I could set the node + broadcast address registers and AddressFiltering bit flag in RegPacketConfig1

My RMRFM69.h modifications

enum moduleType {RFM65, RFM65C, RFM69, RFM69C, RFM69H, RFM69HC};
	
 #define ADDRESS_NODE_DEFAULT 0x0
 #define ADDRESS_BROADCAST_DEFAULT 0x0
 #define ADDRESSING_ENABLED_NODE 0x2
 #define ADDRESSING_ENABLED_NODE_AND_BROADCAST 0x4

	class RMRFM69
	{
	 public:
		 RMRFM69(SPIClass &spiPort, byte csPin, byte dio0Pin, byte rstPin);
		 modulationType Modulation; //OOK/FSK/GFSK
		 moduleType COB;				//Chip on board
		 uint32_t Frequency;			//unit: KHz
		 uint32_t SymbolTime;			//unit: ns
		 uint32_t Devation;				//unit: KHz
		 word BandWidth;				//unit: KHz
		 byte OutputPower;				//unit: dBm   range: 0-31 [-18dBm~+13dBm] for RFM69/RFM69C
										//            range: 0-31 [-11dBm~+20dBm] for RFM69H/RFM69HC
		 word PreambleLength;			//unit: byte

		 bool CrcDisable; //fasle: CRC enable�� & use CCITT 16bit
						  //true : CRC disable
		 bool CrcMode;	//false: CCITT

		 bool FixedPktLength; //false: for contain packet length in Tx message, the same mean with variable lenth
							  //true : for doesn't include packet length in Tx message, the same mean with fixed length
		 bool AesOn;		  //false:
							  //true:
		 bool AfcOn;		  //false:
							  //true:
		 byte SyncLength;	 //unit: none, range: 1-8[Byte], value '0' is not allowed!
		 byte SyncWord[8];
		 byte PayloadLength; //PayloadLength is need to be set a value, when FixedPktLength is true.
		 byte AesKey[16];	//AES Key block, note [0]->[15] == MSB->LSB
		 byte AddressNode = ADDRESS_NODE_DEFAULT;
		 byte AddressBroadcast = ADDRESS_BROADCAST_DEFAULT;

		 void vInitialize(void);
		 void vConfig(void);
		 void vGoRx(void);
		 void vGoStandby(void);
		 void vGoSleep(void);
		 bool bSendMessage(byte msg[], byte length);
		 bool bSendMessage(byte Address, byte msg[], byte length);
		 byte bGetMessage(byte msg[]);
		 void vRF69SetAesKey(void);
		 void vTrigAfc(void);

		 void vDirectRx(void);			  //go continuous rx mode, with init. inside
		 void vChangeFreq(uint32_t freq); //change frequency
		 byte bReadRssi(void);			  //read rssi value
		 void dumpRegisters(Stream& out);
	

My RMRFM69.cpp modifications in vConfig

 if(!CrcDisable)
 	{
 	i += CrcOn;
	if(CrcMode)
		i += CrcCalc_IBM;
	else
		i += CrcCalc_CCITT;
	}

if((AddressNode!=ADDRESS_NODE_DEFAULT) || (AddressBroadcast==ADDRESS_BROADCAST_DEFAULT))
   {
      i += ADDRESSING_ENABLED_NODE;
   }

if((AddressNode!=ADDRESS_NODE_DEFAULT) || (AddressBroadcast!=ADDRESS_BROADCAST_DEFAULT))
  {
     i += ADDRESSING_ENABLED_NODE_AND_BROADCAST;
  }

 vSpiWrite(((word)RegPacketConfig1<<8)+i);		

I also validate the lengths of the messages to be sent taking into account whether encryption is enabled\disabled.

RFM69 hat library receive lockup debugging

Every so often my Enums & Masks test harness locked up and stopped receiving messages from my test rig. This seemed to happen more often when the send functionality of my library was not being used.

easysensors RFM69HCW test rig

After 5 to 30 minutes (a couple of times it was 5 to 8 hours overnight) the application stopped receiving messages and wouldn’t resume until the application (device reset) was restarted or the RegOpmode-Mode was quickly changed to sleep then back to receive.

private void InterruptGpioPin2_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args)
{
    Debug.WriteLine("InterruptGpioPin2_ValueChanged");

    rfm69Device.SetMode(Rfm69HcwDevice.RegOpModeMode.Sleep);
    rfm69Device.SetMode(Rfm69HcwDevice.RegOpModeMode.Receive);
}

After re-reading the Semtech SX1231 datasheet one of the other possible solutions involved writing to the RegPacketConfig2-RestartRX bit

RegPacketConfig2 configuration options

Of the different approaches I found this code was the most reliable way of restarting reception of packets.

private void InterruptGpioPin3_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args)
{
	Debug.WriteLine("InterruptGpioPin3_ValueChanged");

	byte regpacketConfig2 = rfm69Device.RegisterManager.ReadByte(0x3d);
	regpacketConfig2 |= (byte)0x04;
	rfm69Device.RegisterManager.WriteByte(0x3d, regpacketConfig2);
}

I had noticed this code in the Low Power Lab and wondered what it was for. The HopeRF library didn’t appear to have code like this to restart reception which was interesting.

void RFM69::send(uint16_t toAddress, const void* buffer, uint8_t bufferSize, bool requestACK)
{
  writeReg(REG_PACKETCONFIG2, (readReg(REG_PACKETCONFIG2) &amp; 0xFB) | RF_PACKET2_RXRESTART); // avoid RX deadlocks
  uint32_t now = millis();
  while (!canSend() &amp;&amp; millis() - now < RF69_CSMA_LIMIT_MS) receiveDone();
  sendFrame(toAddress, buffer, bufferSize, requestACK, false);
}

// should be called immediately after reception in case sender wants ACK
void RFM69::sendACK(const void* buffer, uint8_t bufferSize) {
  ACK_REQUESTED = 0;   // TWS added to make sure we don't end up in a timing race and infinite loop sending Acks
  uint16_t sender = SENDERID;
  int16_t _RSSI = RSSI; // save payload received RSSI value
  writeReg(REG_PACKETCONFIG2, (readReg(REG_PACKETCONFIG2) &amp; 0xFB) | RF_PACKET2_RXRESTART); // avoid RX deadlocks
  uint32_t now = millis();
  while (!canSend() &amp;&amp; millis() - now < RF69_CSMA_LIMIT_MS) receiveDone();
  SENDERID = sender;    // TWS: Restore SenderID after it gets wiped out by receiveDone()
  sendFrame(sender, buffer, bufferSize, false, true);
  RSSI = _RSSI; // restore payload RSSI
}

void RFM69::receiveBegin() {
  DATALEN = 0;
  SENDERID = 0;
  TARGETID = 0;
  PAYLOADLEN = 0;
  ACK_REQUESTED = 0;
  ACK_RECEIVED = 0;
#if defined(RF69_LISTENMODE_ENABLE)
  RF69_LISTEN_BURST_REMAINING_MS = 0;
#endif
  RSSI = 0;
  if (readReg(REG_IRQFLAGS2) &amp; RF_IRQFLAGS2_PAYLOADREADY)
    writeReg(REG_PACKETCONFIG2, (readReg(REG_PACKETCONFIG2) &amp; 0xFB) | RF_PACKET2_RXRESTART); // avoid RX deadlocks
  writeReg(REG_DIOMAPPING1, RF_DIOMAPPING1_DIO0_01); // set DIO0 to "PAYLOADREADY" in receive mode
  setMode(RF69_MODE_RX);
}

In the debug output you can see that clock frequencies of the two test devices are slightly different. Every so often they transmit close enough to corrupt one of the message payloads which causes the deadlock.

22:20:26.379 Address 0X99 10011001
22:20:26 Received 14 byte message Hello World:10
22:20:26.561 RegIrqFlags2 01100110
22:20:26.576 Address 0X66 01100110
22:20:26 Received 14 byte message Hello World:26
.22:20:27.501 RegIrqFlags2 01100110
22:20:27.517 Address 0X99 10011001
22:20:27 Received 14 byte message Hello World:11
22:20:27.699 RegIrqFlags2 01100110
22:20:27.714 Address 0X66 01100110
22:20:27 Received 14 byte message Hello World:27
...............................

Now I need to back integrate the fix into the send & receive message methods of my code, then stress test the library with even more client devices.

RFM69 hat library receive lockups issue

Sometimes while testing code you notice something odd. Every so often the Enums & Masks application locks up and stops receiving messages from my test rig.

easysensors RFM69HCW test rig

The symptom is that after 5 to 30 minutes the application stops receiving messages

21:37:37.568 RegIrqFlags1 11011001
21:37:37.583 Address 0X99 10011001
21:37:37 Received 14 byte message Hello World:61
..21:37:38.693 RegIrqFlags2 01100110
21:37:38.706 RegIrqFlags1 11011001
21:37:38.724 Address 0X99 10011001
21:37:38 Received 14 byte message Hello World:62
............The thread 0xba8 has exited with code 0 (0x0).
.................................................................................................................................................The thread 0xf90 has exited with code 0 (0x0).
.....................The thread 0xe30 has exited with code 0 (0x0).
.......................The thread 0xa04 has exited with code 0 (0x0).
................................The thread 0xc8c has exited with code 0 (0x0).
..........................................................................................The thread 0xc38 has exited with code 0 (0x0).
......................The thread 0xf68 has exited with code 0 (0x0).
......................................................................................The thread 0x1c8 has exited with code 0 (0x0).
..........The thread 0xeb8 has exited with code 0 (0x0).
..............................................................The thread 0xbb8 has exited with code 0 (0x0).
..........The thread 0xdc0 has exited with code 0 (0x0).
...............................The thread 0x820 has exited with code 0 (0x0).
....................................The thread 0xaac has exited with code 0 (0x0).
......The thread 0xbf0 has exited with code 0 (0x0).
............................................The thread 0x4e8 has exited with code 0 (0x0).
...............................The thread 0x1b4 has exited with code 0 (0x0).
...............................................................The thread 0xbdc has exited with code 0 (0x0).
....................The thread 0xb60 has exited with code 0 (0x0).
.........................................................................................................The thread 0x510 has exited with code 0 (0x0).
........The thread 0xf60 has exited with code 0 (0x0).
........................................................The thread 0x3c0 has exited with code 0 (0x0).
......................................The thread 0xa4c has exited with code 0 (0x0).
..................................................................The thread 0x9e0 has exited with code 0 (0x0).
....................The thread 0xd74 has exited with code 0 (0x0).
............................The thread 0xfa0 has exited with code 0 (0x0).
..................................................................................................The thread 0xfe0 has exited with code 0 (0x0).
....................................................................................The thread 0xdd4 has exited with code 0 (0x0).
........................The thread 0xc00 has exited with code 0 (0x0).
..................................The thread 0x478 has exited with code 0 (0x0).
.........................The thread 0x88c has exited with code 0 (0x0).
...........................................The thread 0x280 has exited with code 0 (0x0).
..........................................The thread 0x8e4 has exited with code 0 (0x0).
............The thread 0x410 has exited with code 0 (0x0).
..............................................The thread 0xa70 has exited with code 0 (0x0).
................The thread 0x994 has exited with code 0 (0x0).
....................The thread 0x298 has exited with code 0 (0x0).
..............The thread 0x3a4 has exited with code 0 (0x0).
............................................................The thread 0xa2c has exited with code 0 (0x0).
..........The thread 0x208 has exited with code 0 (0x0).
..........................................................................The thread 0xbd4 has exited with code 0 (0x0).
............The thread 0xfdc has exited with code 0 (0x0).
........................................................................The thread 0x36c has exited with code 0 (0x0).
...........22:08:57.638 RegIrqFlags2 01100110
22:08:57.658 RegIrqFlags1 11011001
22:08:57.676 Address 0X66 01100110
22:08:57 Received 15 byte message Hello World:157
22:08:57.807 RegIrqFlags2 01100110

But, every so often it would after many minutes start up again without me doing anything (I noticed this after leaving application running overnight). I could get the application to restart by putting a break point on the Debug.Write(“.”) and toggling the OperationMode from Sleep to Receive

Using Visual Studio Immediate Windows to execute SetMode

I have found if the device is transmitting every so often the lockups are also much less likely. To help with debugging the issue I have wired up the three buttons on the Adafruit Radio Bonnet to call different diagnostic code

public void Run(IBackgroundTaskInstance taskInstance)
{
	byte[] syncValues = { 0xAA, 0x2D, 0xD4 };
	byte[] aesKeyValues = { 0x0, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0X0E, 0X0F };

	GpioController gpioController = GpioController.GetDefault();

	InterruptGpioPin1 = gpioController.OpenPin(5);
	InterruptGpioPin1.SetDriveMode(GpioPinDriveMode.InputPullUp);
	InterruptGpioPin1.ValueChanged += InterruptGpioPin1_ValueChanged; ;

	InterruptGpioPin1 = gpioController.OpenPin(6);
	InterruptGpioPin1.SetDriveMode(GpioPinDriveMode.InputPullUp);
	InterruptGpioPin1.ValueChanged += InterruptGpioPin2_ValueChanged; ;

	InterruptGpioPin1 = gpioController.OpenPin(12);
	InterruptGpioPin1.SetDriveMode(GpioPinDriveMode.InputPullUp);
	InterruptGpioPin1.ValueChanged += InterruptGpioPin3_ValueChanged; ;

…

private void InterruptGpioPin1_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args)
{
   Debug.WriteLine("InterruptGpioPin1_ValueChanged");
   rfm69Device.SetMode(Rfm69HcwDevice.RegOpModeMode.Sleep);
   rfm69Device.SetMode(Rfm69HcwDevice.RegOpModeMode.Receive);
}

private void InterruptGpioPin2_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args)
{
   Debug.WriteLine("Receive-Wait");
   byte IrqFlags = rfm69Device.RegisterManager.ReadByte(0x28); // RegIrqFlags2
   while ((IrqFlags &amp; 0b00000100) == 0)  // wait until PayLoadReady set
   {
      Task.Delay(20).Wait();
      IrqFlags = rfm69Device.RegisterManager.ReadByte(0x28); // RegIrqFlags2
      Debug.WriteLine(string.Format("RegIrqFlags {0}", Convert.ToString((byte)IrqFlags, 2).PadLeft(8, '0')));
       Debug.Write(".");
   }
   Debug.WriteLine("");

   // Read the length
   byte numberOfBytes = rfm69Device.RegisterManager.ReadByte(0x0);

   // Allocate buffer for message
   byte[] messageBytes = new byte[numberOfBytes];

  for (int i = 0; i < numberOfBytes; i++)
  {
     messageBytes[i] = rfm69Device.RegisterManager.ReadByte(0x00); // RegFifo
   }

  string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
  Debug.WriteLine("Received {0} byte message {1}", messageBytes.Length, messageText);

  Debug.WriteLine("Receive-Done");
}

private void InterruptGpioPin3_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args)
{
   Debug.WriteLine("Receive-No wait");

  // Read the length
  byte numberOfBytes = rfm69Device.RegisterManager.ReadByte(0x0);

  // Allocate buffer for message
  byte[] messageBytes = new byte[numberOfBytes];

  for (int i = 0; i < numberOfBytes; i++)
  {
      messageBytes[i] = rfm69Device.RegisterManager.ReadByte(0x00); // RegFifo
   }

  string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
  Debug.WriteLine("Received {0} byte message {1}", messageBytes.Length, messageText);

  Debug.WriteLine("Receive-Done");
}

Looks like this maybe a bit of a heisenbug as it takes a longish time to appear and poking around in the debugger and adding more diagnostics changes the frequency the error.

Received 16 byte message 
Receive-Done
.............................Receive-No wait
Received 16 byte message 
Receive-Done
Receive-No wait
Received 16 byte message 
Receive-Done
....Receive-No wait
Received 16 byte message 
Receive-Done
Receive-No wait
Received 16 byte message 
Receive-Done
.............

Pressing button one restarts inbound messages for a while, button two sits in an endless loop, button three reads in a 16 byte message of 0x10 characters, which I think is buffer length. I have added code to catch exceptions and stop re-entrancy but it never seems to get triggered.

private void InterruptGpioPin_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs args)
{
	if (args.Edge != GpioPinEdge.RisingEdge)
	{
		return;
	}

	if (InIrqHandler)
	{
		Debug.WriteLine("{0:HH:mm:ss.fff} InIrqHandler+++++++++++++++++++++++++++++++++++++++++++++++++++++++++", DateTime.Now);
		return;
	}
	InIrqHandler = true;

	try
	{
		RegIrqFlags2 irqFlags2 = (RegIrqFlags2)RegisterManager.ReadByte((byte)Registers.RegIrqFlags2);
		Debug.WriteLine("{0:HH:mm:ss.fff} RegIrqFlags2 {1}", DateTime.Now, Convert.ToString((byte)irqFlags2, 2).PadLeft(8, '0'));

		if ((irqFlags2 &amp; RegIrqFlags2.PayloadReady) == RegIrqFlags2.PayloadReady)
		{
			if ((irqFlags2 &amp; RegIrqFlags2.CrcOk) == RegIrqFlags2.CrcOk)
			{
				RegIrqFlags1 irqFlags1 = (RegIrqFlags1)RegisterManager.ReadByte((byte)Registers.RegIrqFlags1); // RegIrqFlags1

				//	SetMode(RegOpModeMode.Sleep);

				// Read the length of the buffer
				byte numberOfBytes = RegisterManager.ReadByte(0x0);
					Debug.WriteLine("{0:HH:mm:ss.fff} RegIrqFlags1 {1}", DateTime.Now, Convert.ToString((byte)irqFlags1, 2).PadLeft(8, '0'));
				if (((irqFlags1 &amp; RegIrqFlags1.SynAddressMatch) == RegIrqFlags1.SynAddressMatch) &amp;&amp; DeviceAddressingEnabled)
				{
					byte address = RegisterManager.ReadByte(0x0);
					Debug.WriteLine("{0:HH:mm:ss.fff} Address 0X{1:X2} {2}", DateTime.Now, address, Convert.ToString((byte)address, 2).PadLeft(8, '0'));
					numberOfBytes--;
				}

				// Allocate buffer for message
				byte[] messageBytes = new byte[numberOfBytes];

				for (int i = 0; i < numberOfBytes; i++)
				{
					messageBytes[i] = RegisterManager.ReadByte(0x00); // RegFifo
				}
				//SetMode(RegOpModeMode.Receive);

				string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
					Debug.WriteLine("{0:HH:mm:ss} Received {1} byte message {2}", DateTime.Now, messageBytes.Length, messageText);
			}
			else
			{
				Debug.WriteLine("{0:HH:mm:ss} Received message CRC NOK++++++++++++", DateTime.Now);
			}
		}

		if ((irqFlags2 &amp; RegIrqFlags2.PacketSent) == RegIrqFlags2.PacketSent)  // PacketSent set
		{
			RegisterManager.WriteByte(0x01, 0b00010000); // RegOpMode set ReceiveMode
			Debug.WriteLine("{0:HH:mm:ss.fff} Transmit-Done", DateTime.Now);
		}
	}
	catch (Exception ex)
	{
		Debug.WriteLine($"################### {ex.Source}");
		Debug.WriteLine($"################### {ex.Message}");
		Debug.WriteLine($"################### {ex.StackTrace}");
	}
	finally
	{
		InIrqHandler = false;
	}
}


I need to have a look at the Low Power Lab and HopeRF libraries to see how they handle message received interrupts.

RFM69 hat library Part12C

Enums and Masks – Synchronisation

The RFM69CW/RFM69HCW module (based on the Semtech SX1231/SX1231H) has configurable (RegSyncConfig) synchronisation sequences (the length, tolerance for errors and the individual byte values).

By default synchronisation is enabled and a default sequence of bytes is used, in my library synchronisation is NOT enabled until a SyncValue is provided.

I added some additional constants and enumerations for the other settings configured in RegSyncConfig.

// RegSyncConfig 
// This is private because default ignored and flag set based on SyncValues parameter being specified rather than default
private enum RegSyncConfigSyncOn
{
	Off = 0b00000000,
	On = 0b10000000
}

public enum RegSyncConfigFifoFileCondition
{
	SyncAddressInterrupt = 0b00000000,
	FifoFillCondition =    0b01000000
}

private const RegSyncConfigFifoFileCondition SyncFifoFileConditionDefault = RegSyncConfigFifoFileCondition.SyncAddressInterrupt;
readonly byte[] SyncValuesDefault = {0x01, 0x01, 0x01, 0x01};
public const byte SyncValuesSizeDefault = 4;
public const byte SyncValuesSizeMinimum = 1;
public const byte SyncValuesSizeMaximum = 8;

private const byte SyncToleranceDefault = 0;
public const byte SyncToleranceMinimum = 0;
public const byte SyncToleranceMaximum = 7;

I also added some guard conditions to the initialise method which validate the syncFifoFileCondition, syncTolerance and syncValues length.

public void Initialise(RegOpModeMode modeAfterInitialise,
	BitRate bitRate = BitRateDefault,
	ushort frequencyDeviation = frequencyDeviationDefault,
	double frequency = FrequencyDefault,
	ListenModeIdleResolution listenModeIdleResolution = ListenModeIdleResolutionDefault, ListenModeRXTime listenModeRXTime = ListenModeRXTimeDefault, ListenModeCrieria listenModeCrieria = ListenModeCrieriaDefault, ListenModeEnd listenModeEnd = ListenModeEndDefault,
	byte listenCoefficientIdle = ListenCoefficientIdleDefault,
	byte listenCoefficientReceive = ListenCoefficientReceiveDefault,
	bool pa0On = pa0OnDefault, bool pa1On = pa1OnDefaut, bool pa2On = pa2OnDefault, byte outputpower = OutputpowerDefault,
	PaRamp paRamp = PaRampDefault,
	bool ocpOn = OcpOnDefault, byte ocpTrim = OcpTrimDefault,
	LnaZin lnaZin = LnaZinDefault, LnaCurrentGain lnaCurrentGain = LnaCurrentGainDefault, LnaGainSelect lnaGainSelect = LnaGainSelectDefault,
	byte dccFrequency = DccFrequencyDefault, RxBwMant rxBwMant = RxBwMantDefault, byte RxBwExp = RxBwExpDefault,
	byte dccFreqAfc = DccFreqAfcDefault, byte rxBwMantAfc = RxBwMantAfcDefault, byte bxBwExpAfc = RxBwExpAfcDefault,
	ushort preambleSize = PreambleSizeDefault,
	RegSyncConfigFifoFileCondition? syncFifoFileCondition = null, byte? syncTolerance = null, byte[] syncValues = null,
	RegPacketConfig1PacketFormat packetFormat = RegPacketConfig1PacketFormat.FixedLength,
	RegPacketConfig1DcFree packetDcFree = RegPacketConfig1DcFreeDefault,
	bool packetCrc = PacketCrcOnDefault,
	bool packetCrcAutoClearOff = PacketCrcAutoClearOffDefault,
	RegPacketConfig1CrcAddressFiltering packetAddressFiltering = PacketAddressFilteringDefault,
	byte payloadLength = PayloadLengthDefault,
	byte addressNode = NodeAddressDefault, byte addressbroadcast = BroadcastAddressDefault,
	TxStartCondition txStartCondition = TxStartConditionDefault, byte fifoThreshold = FifoThresholdDefault,
	byte interPacketRxDelay = InterPacketRxDelayDefault, bool restartRx = RestartRxDefault, bool autoRestartRx = AutoRestartRxDefault,
	byte[] aesKey = null
	)
{
	RegOpModeModeCurrent = modeAfterInitialise;
	PacketFormat = packetFormat;

	#region RegSyncConfig + RegSyncValue1 to RegSyncValue8 guard conditions
	if (syncValues != null)
	{
		// If sync enabled (i.e. SyncValues array provided) check that SyncValues not to short/long and SyncTolerance not to small/big
		if ((syncValues.Length < SyncValuesSizeMinimum) || (syncValues.Length &gt; SyncValuesSizeMaximum))
		{
			throw new ArgumentException($"The syncValues array length must be between {SyncValuesSizeMinimum} and {SyncValuesSizeMaximum} bytes", "syncValues");
		}
		if (syncTolerance.HasValue)
		{
			if ((syncTolerance < SyncToleranceMinimum) || (syncTolerance &gt; SyncToleranceMaximum))
			{
				throw new ArgumentException($"The syncTolerance size must be between {SyncToleranceMinimum} and {SyncToleranceMaximum}", "syncTolerance");
			}
		}
	}
	else
	{
		// If sync not enabled (i.e. SyncValues array null) check that no syncFifoFileCondition or syncTolerance configuration specified
		if (syncFifoFileCondition.HasValue)
		{
			throw new ArgumentException($"If Sync not enabled syncFifoFileCondition is not supported", "syncFifoFileCondition");
		}

		if (syncTolerance.HasValue)
		{
			throw new ArgumentException($"If Sync not enabled SyncTolerance is not supported", "syncTolerance");
		}
	}
	#endregion

I also ensure that the syncFifoFileCondition and syncTolerance are not specified if synchronisation is not enabled.

The Arduino client code works though I need modify it so I can do more testing of the initialise method parameter options.