Universal RFM69HCW / SX1231 Driver (MCAL-Based)

This is a portable, hardware-agnostic C driver for the RFM69HCW / SX1231 RF transceiver. Originally built for STM32 (HAL), it can now be easily ported to any microcontroller (ESP32, Arduino, Raspberry Pi Pico...) without touching the core logic, thanks to a lightweight MCAL (Microcontroller Abstraction Layer).

This library provides a way of controlling the radio module over SPI, configuring packet or raw modes.

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📖 Documentation

To help you understand or modify the project, the documentation has been split into detailed sections:

• 💻 RFM69HCW Packet Mode Details — Understand how to make a simple communication using Packet Mode
• 📊 RFM69HCW RAW Mode Details — Understand how to use RAW Mode
• 🔒 Payload Encryption Guide — How to secure your data using external cryptographic libraries.
• 🪲 Debug — Simple Debug Implementation
• 🚨 TroubleShooting — Many response to a lot of error...

✨ Implemented Features

🔧 Core API

• RFM69_WriteReg → Write a value in a register
• RFM69_ReadReg → Read a register value

Full reference

Core API	Description	Example
RFM69_WriteReg	Write a value in a register	RFM69_WriteReg(0x37, 0x90);
RFM69_ReadReg	Read a value in a register	uint8_t currentVal = RFM69_ReadReg(0x02);

⚙️ Radio Initialisation

• RFM69_Init → Initialize SPI interface and Chip Select pin
• RFM69_SetMode → Select operating mode type
• RFM69_GetMode → Get operating mode

Full reference

Radio Initialization	Description	Example/Available Modes
RFM69_Init	Initialize SPI interface and Chip Select pin	RFM69_Init(&hspi1, GPIOC, GPIO_PIN_7);
RFM69_SetMode	Select operating mode type	RFM69_MODE_SLEEP RFM69_MODE_STDBY RFM69_MODE_FS RFM69_MODE_TX RFM69_MODE_RX
RFM69_GetMode	Get operating mode	Return RFM69_Mode_t : RFM69_MODE_SLEEP RFM69_MODE_STDBY RFM69_MODE_FS RFM69_MODE_TX RFM69_MODE_RX

📡 Radio Configuration

• RFM69_SetFrequencyTo433 → Set Frequency to 433 MHz
• RFM69_SetBitrate → Set bitrate of communication
• RFM69_GetBitrate → Get bitrate of communication
• RFM69_AutoSetFdev → Automatically adjusts frequency deviation based on bitrate for FSK Modulation
• RFM69_GetFdev → Get frequency deviation based on bitrate with FSK Modulation
• RFM69_SetModulationType → Set modulation type
• RFM69_GetModulationType → Get modulation type
• RFM69_SetDataProcessingMode → Set Data Processing type
• RFM69_GetDataProcessingMode → Get Data Processing type
• RFM69_SetDataShaping → Set Data Shaping type
• RFM69_GetDataShaping → Get Data Shaping type
• RFM69_WaitForPLLLock → Wait For PLL Lock
• RFM69_WaitForTxReady → Wait For Tx Mode Ready

Full reference

Radio Configuration	Description	Example/Available Modes
RFM69_SetFrequencyTo433	Set Frequency to 433 MHz
RFM69_SetBitrate	Set bitrate of communication : 4.8 kbps = 4800	RFM69_SetBitrate(4800);
RFM69_GetBitrate	Get bitrate of communication	uint32_t Bitrate = RFM69_GetBitrate();
RFM69_AutoSetFdev	Automatically adjusts frequency deviation based on bitrate for FSK Modulation	RFM69_AutoSetFdev();
RFM69_GetFdev	Get frequency deviation based on bitrate	uint32_t Fdev = RFM69_GetFdev();
RFM69_SetModulationType	Set Modulation type	RFM69_MODUL_FSK RFM69_MODUL_OOK
RFM69_GetModulationType	Get Modulation type	RFM69_Modulation_t RFM69_GetModulationType(void)
RFM69_SetDataProcessingMode	Select Data Processing type	RFM69_PACKET_MODE RFM69_CONTINUOUS_SYNC RFM69_CONTINUOUS_RAW
RFM69_GetDataProcessingMode	Get Data Processing type	RFM69_DataProcessingMode_t RFM69_GetDataProcessingMode(void)
RFM69_SetDataShaping	Select Data Shaping type	RFM69_SHAPING_NONE RFM69_SHAPING_Gaussianfilter_BT1 RFM69_SHAPING_Gaussianfilter_BT05 RFM69_SHAPING_Gaussianfilter_BT03
RFM69_GetDataShaping	Get Data Shaping type	RFM69_Data_Shaping_t RFM69_GetDataShaping(void)
RFM69_WaitForPLLLock	Wait For PLL Lock
RFM69_WaitForTxReady	Wait For Tx Mode Ready

📶 Packet Engine

• RFM69_SetKeyValues_Sync → Set Key to link two modules.
• RFM69_SetPacketConfig → Select Packet Configuration
• RFM69_AutoMessageDetectionReceive_Config → Select Automatic Receive Packet Configuration
• RFM69_FlushFIFO → Flush FIFO
• RFM69_SendMessage_Packet_Mode → Send message
• RFM69_ReceiveMessage_Packet_Mode → Read a message received

Full reference

Modulation & Packet Engine	Description	Example/Available Modes
RFM69_SetKeyValues_Sync	Set Key to link two modules. Must be identical on both modules Max key length 8	uint8_t mykey[] = {0x42, 0x24}; RFM69_SetSyncValues(mykey, 2);
RFM69_SetPacketConfig	Select Packet Configuration	RFM69_PACKET_FORMAT_FIXED RFM69_PACKET__FORMAT_VARIABLE RFM69_DC_FREE_NONE RFM69_DC_FREE_MANCHESTER RFM69_DC_FREE_WHITENING RFM69_CRC_OFF RFM69_CRC_ON RFM69_CRC_AUTOCLEAR_ON RFM69_CRC_AUTOCLEAR_OFF RFM69_FILTER_NONE RFM69_FILTER_NODE RFM69_FILTER_NODE_BROADCAST
RFM69_AutoMessageDetectionReceive_Config	Choose type of syncing between two module	RFM69_SYNC_OFF RFM69_SYNC_ON RFM69_FIFO_FILL_IF_SYNC RFM69_FIFO_FILL_ALWAYS RFM69_SYNC_TOLERANCE_ERROR_0 RFM69_SYNC_TOLERANCE_ERROR_1 RFM69_SYNC_TOLERANCE_ERROR_2 RFM69_SYNC_TOLERANCE_ERROR_3 RFM69_SYNC_TOLERANCE_ERROR_4 RFM69_SYNC_TOLERANCE_ERROR_5 RFM69_SYNC_TOLERANCE_ERROR_6 RFM69_SYNC_TOLERANCE_ERROR_7
RFM69_FlushFIFO	Flush FIFO
RFM69_SendMessage_Packet_Mode	Send message uint8_t message[] = "SATELLITE_TEST"; RFM69_SendMessage( message, 14);
RFM69_ReceiveMessage_Packet_Mode	Read a message received	uint8_t receivedLen = RFM69_ReceiveMessage_Packet_Mode(rxBuffer, 64);

📶 RAW Mode

• RFM69_SetDefaultDioMapping → Set DIO Mapping Default (Important if you use RAW Mode)
• RFM69_Text_To_Binary_Payload → Transform Text to Binary format
• RFM69_RAW_FillUp_Playload → Fill Up Playload before sending
• RFM69_RAW_DATA_SEND → Automatic Send Message in RAW Mode
• RFM69_RAW_Transmit_Byte → Transmit byte over radio with bit stuffing
• RFM69_RAW_CRC16_Calculation_Buffer → Calculate CRC16 for error check
• RFM69_Pad_To_256 → Complete Data buffer to be up to 256 bytes
• CRC_CHECK → CRC Check

Full reference

Function	Description	Example/Available Modes
RFM69_SetDefaultDioMapping	Set DIO Mapping Default (Important if you use RAW Mode)	By default DIO1 is DCLK (Clock)
RFM69_Text_To_Binary_Payload	Transform Text to Binary format
RFM69_RAW_FillUp_Payload	Fill Up Playload before sending
RFM69_RAW_DATA_SEND	Automatic Send Message in RAW Mode
RFM69_RAW_Transmit_Byte	Transmit byte over radio with bit stuffing	void RFM69_RAW_Transmit_Byte(uint8_t data, uint8_t enable_stuffing)
RFM69_RAW_CRC16_Calculation_Buffer	Calculate CRC16 for error check
RFM69_Pad_To_256	Complete Data buffer to be up to 256 bytes
CRC_CHECK	CRC Check

📤 Transmission Parameters

• RFM69_PowerAmplifierSelection → Select Power Amplifier type Pout = PA_... + OutputPower [dBm]
• RFM69_GetPowerAmplifier → Get Power Amplifier type

Full reference

Transmission	Description	Example/Available Modes
RFM69_PowerAmplifierSelection	Select Power Amplifier type Pout = PA_... + OutputPower [dBm]	PA_0 => Start from -18 to +13 dbm PA_1 => Start from -18 to +13 dbm PA_1_2 => Start from -14 to +17 dbm PA_HIGH_POWER => Start from -11 to +20 dbm
RFM69_GetPowerAmplifier	Get Power Amplifier type	RFM69_PA_Select_t RFM69_GetPowerAmplifier(void)

📥 Reception Parameters

• RFM69_RSSI → Visualize RSSI in dBm
• RFM69_SetLnaImpedance → Set LNA Impedance (Z) In
• RFM69_SetLnaGain → Set LNA Gain
• RFM69_GetLnaStatus → Get LNA Configuration
• RFM69_StartAFC → Start Frequency Recalibration AFC
• RFM69_Status_RecalibrationFrequencyAFC → Get Status of the Automatic Recalibration Frequency Correction AFC
• RFM69_GetAFCCorrectionHz → Read AFC Correction in Hz
• RFM69_ClearAfc → Clear Frequency Recalibration AFC
• RFM69_SetAfcAuto → Activate/Deactive Automatic Frequency Recalibration AFC
• RFM69_SetAfcAutoclear → Activate/Deactive Clearing Automatic Frequency Recalibration AFC
• RFM69_StartFEI → Start Measurement Of Error Frequency in Hz FEI
• RFM69_Status_ReadingErrorFrequency → Get Status of the Reading Error Frequency FEI
• RFM69_GetFrequencyErrorFeiHz → Read Error Frequency in Hz FEI

Full reference

Reception	Description	Example/Available Modes
RFM69_RSSI	Visualize RSSI in dBm	Return an uint8_t ;
RFM69_SetLnaImpedance	Set LNA Impedance (Z) In	LNA_Impedance_50 LNA_Impedance_200
RFM69_SetLnaGain	Set LNA Gain	LNA_GAIN_AUTO LNA_GAIN_G1 LNA_GAIN_G2 LNA_GAIN_G3 LNA_GAIN_G4 LNA_GAIN_G4 LNA_GAIN_G5 LNA_GAIN_G6
RFM69_GetLnaStatus	Get LNA Configuration
RFM69_StartAFC	Start Frequency Recalibration AFC
RFM69_Status_RecalibrationFrequencyAFC	Get Status of the Automatic Recalibration Frequency Correction AFC
RFM69_GetAFCCorrectionHz	Read AFC Correction in Hz
RFM69_ClearAfc	Clear Frequency Recalibration AFC
RFM69_SetAfcAuto	Activate/Deactive Automatic Frequency Recalibration AFC	AFC_AUTO_OFF AFC_AUTO_ON
RFM69_SetAfcAutoclear	Activate/Deactive Automatic Frequency Recalibration AFC	AFC_AUTOCLEAR_OFF AFC_AUTOCLEAR_ON
RFM69_StartFEI	Start Measurement Of Error Frequency in Hz FEI
RFM69_Status_ReadingErrorFrequency	Get Status of the Reading Error Frequency FEI
RFM69_GetFrequencyErrorFeiHz	Read Error Frequency in Hz FEI

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💡 SPI Tested configuration

The SPI was configured as follows:

• Frame Format : Motorola
• Mode : Full-Duplex Master
• CPOL : Low
• CPHA : 2 Edge
• First Bit : MSB First

🚀 How to Port the Driver to Another Microcontroller

Porting this driver to a new platform requires zero modifications to the RFM69HCW.c file. Everything happens in the header configuration (MCAL_RFM69HCW.h).

You simply need to map the MCAL_RFM69H_... macros to your new platform's specific libraries.

🔗 Resources & Links

• Official Website
• Datasheet RFM69HCW
• Adafruit Learning Guide

📄 License

This project is licensed under the Mozilla Public License 2.0 (MPL-2.0).

Note

To use the printf debug feature on STM32, make sure you have redirected stdout to your UART peripheral (by overriding the _write function).