TinyLoRa.h

/*!
 * @file TinyLoRa.h
 *
 * This is part of Adafruit's TinyLoRa library for the Arduino platform. It is
 * designed specifically to work with the Adafruit Feather 32u4 RFM95 LoRa:
 * https://www.adafruit.com/product/3078
 *
 * This library uses SPI to communicate, 4 pins (SCL, SDA, IRQ, SS)
 * are required to interface with the HopeRF RFM95/96 breakout.
 *
 * Adafruit invests time and resources providing this open source code,
 * please support Adafruit and open-source hardware by purchasing
 * products from Adafruit!
 *
 * Copyright 2015, 2016 Ideetron B.V.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Modified by Brent Rubell for Adafruit Industries.
 *
 * LGPL license, all text here must be included in any redistribution.
 *
 */

#ifndef TINY_LORA_H
#define TINY_LORA_H

#include <Arduino.h>
#if defined(ARDUINO_ARCH_AVR)
#include <avr/pgmspace.h>
#elif defined(ARDUINO_ARCH_ESP32)
#include <pgmspace.h>
#endif

// uncomment for debug output
// #define DEBUG

/** RFM channel options */
typedef enum rfm_channels {
  CH0,
  CH1,
  CH2,
  CH3,
  CH4,
  CH5,
  CH6,
  CH7,
  MULTI,
} rfm_channels_t;

/** RFM fixed datarate, dependent on region */
typedef enum rfm_datarates {
  SF7BW125,
  SF7BW250,
  SF8BW125,
  SF9BW125,
  SF10BW125,
  SF11BW125,
  SF12BW125,
} rfm_datarates_t;

/** Region configuration*/
#if !defined(EU863) && !defined(AU915) && !defined(AS920)
#define US902 ///< Used in USA, Canada and South America
#endif
//#define EU863 ///< Used in Europe
//#define AU915 ///< Used in Australia
//#define AS920 ///< Used in Asia

#define RFM9x_VER 0x12 ///< Expected RFM9x RegVersion

/* RFM Modes */
#define MODE_SLEEP 0x00 ///< low-power mode
#define MODE_LORA 0x80  ///< LoRa operating mode
#define MODE_STDBY 0x01 ///< Osc. and baseband disabled
#define MODE_TX 0x83    ///< Configures and transmits packet

/* RFM Registers */
#define REG_PA_CONFIG 0x09    ///< PA selection and Output Power control
#define REG_PA_DAC 0x4D       ///< PA Higher Power Settings
#define REG_PREAMBLE_MSB 0x20 ///< Preamble Length, MSB
#define REG_PREAMBLE_LSB 0x21 ///< Preamble Length, LSB
#define REG_FRF_MSB 0x06      ///< RF Carrier Frequency MSB
#define REG_FRF_MID 0x07      ///< RF Carrier Frequency Intermediate
#define REG_FRF_LSB 0x08      ///< RF Carrier Frequency LSB
#define REG_FEI_LSB 0x1E      ///< Info from Prev. Header
#define REG_FEI_MSB 0x1D      ///< Number of received bytes
#define REG_MODEM_CONFIG 0x26 ///< Modem configuration register
#define REG_VER 0x42          ///< RFM9x version register

/**************************************************************************/
/*!
    @brief  TinyLoRa Class
*/
/**************************************************************************/
class TinyLoRa {
public:
  uint8_t txrandomNum;   ///< random number for AES
  uint16_t frameCounter; ///< frame counter
  void setChannel(rfm_channels_t channel);
  void setDatarate(rfm_datarates_t datarate);
  void setPower(int8_t Tx_Power = 17);
  TinyLoRa(int8_t rfm_dio0, int8_t rfm_nss, int8_t rfm_rst);
  bool begin(void);
  void sendData(unsigned char *Data, unsigned char Data_Length,
                unsigned int Frame_Counter_Tx, uint8_t Frame_Port = 1);

private:
  uint8_t randomNum;
  int8_t _cs, _irq, _rst;
  bool _isMultiChan;
  unsigned char _rfmMSB, _rfmMID, _rfmLSB, _sf, _bw, _modemcfg;
  static const unsigned char LoRa_Frequency[8][3];
  static const unsigned char S_Table[16][16];
  void RFM_Send_Package(unsigned char *RFM_Tx_Package,
                        unsigned char Package_Length);
  void RFM_Write(unsigned char RFM_Address, unsigned char RFM_Data);
  uint8_t RFM_Read(uint8_t RFM_Address);
  void Encrypt_Payload(unsigned char *Data, unsigned char Data_Length,
                       unsigned int Frame_Counter, unsigned char Direction);
  void Calculate_MIC(unsigned char *Data, unsigned char *Final_MIC,
                     unsigned char Data_Length, unsigned int Frame_Counter,
                     unsigned char Direction);
  void Generate_Keys(unsigned char *K1, unsigned char *K2);
  void Shift_Left(unsigned char *Data);
  void XOR(unsigned char *New_Data, unsigned char *Old_Data);
  void AES_Encrypt(unsigned char *Data, unsigned char *Key);
  void AES_Add_Round_Key(unsigned char *Round_Key, unsigned char (*State)[4]);
  unsigned char AES_Sub_Byte(unsigned char Byte);
  void AES_Shift_Rows(unsigned char (*State)[4]);
  void AES_Mix_Collums(unsigned char (*State)[4]);
  void AES_Calculate_Round_Key(unsigned char Round, unsigned char *Round_Key);
};

#endif