Quick & dirty port of the RadioHead library with minimal support for the RF95 radio. It is designed to be used with the swspi library which in turn is designed to be used on the MAX32630FTHR board.

Dependents:   Rocket

RH_RF95.h

Committer:
danjulio
Date:
2017-06-11
Revision:
0:e69d086cb053

File content as of revision 0:e69d086cb053:

// RH_RF95.h
//
// Definitions for HopeRF LoRa radios per:
// http://www.hoperf.com/upload/rf/RFM95_96_97_98W.pdf
// http://www.hoperf.cn/upload/rfchip/RF96_97_98.pdf
//
// Author: Mike McCauley (mikem@airspayce.com)
// Copyright (C) 2014 Mike McCauley
// $Id: RH_RF95.h,v 1.16 2017/03/04 00:59:41 mikem Exp $
//
// Ported to mbed - support only a single radio - Dan Julio - 5/2017 
// 

#ifndef RH_RF95_h
#define RH_RF95_h

#include <RHGenericDriver.h>
#include "swspi.h"

// Max number of octets the LORA Rx/Tx FIFO can hold
#define RH_RF95_FIFO_SIZE 255

// This is the maximum number of bytes that can be carried by the LORA.
// We use some for headers, keeping fewer for RadioHead messages
#define RH_RF95_MAX_PAYLOAD_LEN RH_RF95_FIFO_SIZE

// The length of the headers we add.
// The headers are inside the LORA's payload
#define RH_RF95_HEADER_LEN 4

// This is the maximum message length that can be supported by this driver. 
// Can be pre-defined to a smaller size (to save SRAM) prior to including this header
// Here we allow for 1 byte message length, 4 bytes headers, user data and 2 bytes of FCS
#ifndef RH_RF95_MAX_MESSAGE_LEN
 #define RH_RF95_MAX_MESSAGE_LEN (RH_RF95_MAX_PAYLOAD_LEN - RH_RF95_HEADER_LEN)
#endif

// The crystal oscillator frequency of the module
#define RH_RF95_FXOSC 32000000.0

// The Frequency Synthesizer step = RH_RF95_FXOSC / 2^^19
#define RH_RF95_FSTEP  (RH_RF95_FXOSC / 524288)


// Register names (LoRa Mode, from table 85)
#define RH_RF95_REG_00_FIFO                                0x00
#define RH_RF95_REG_01_OP_MODE                             0x01
#define RH_RF95_REG_02_RESERVED                            0x02
#define RH_RF95_REG_03_RESERVED                            0x03
#define RH_RF95_REG_04_RESERVED                            0x04
#define RH_RF95_REG_05_RESERVED                            0x05
#define RH_RF95_REG_06_FRF_MSB                             0x06
#define RH_RF95_REG_07_FRF_MID                             0x07
#define RH_RF95_REG_08_FRF_LSB                             0x08
#define RH_RF95_REG_09_PA_CONFIG                           0x09
#define RH_RF95_REG_0A_PA_RAMP                             0x0a
#define RH_RF95_REG_0B_OCP                                 0x0b
#define RH_RF95_REG_0C_LNA                                 0x0c
#define RH_RF95_REG_0D_FIFO_ADDR_PTR                       0x0d
#define RH_RF95_REG_0E_FIFO_TX_BASE_ADDR                   0x0e
#define RH_RF95_REG_0F_FIFO_RX_BASE_ADDR                   0x0f
#define RH_RF95_REG_10_FIFO_RX_CURRENT_ADDR                0x10
#define RH_RF95_REG_11_IRQ_FLAGS_MASK                      0x11
#define RH_RF95_REG_12_IRQ_FLAGS                           0x12
#define RH_RF95_REG_13_RX_NB_BYTES                         0x13
#define RH_RF95_REG_14_RX_HEADER_CNT_VALUE_MSB             0x14
#define RH_RF95_REG_15_RX_HEADER_CNT_VALUE_LSB             0x15
#define RH_RF95_REG_16_RX_PACKET_CNT_VALUE_MSB             0x16
#define RH_RF95_REG_17_RX_PACKET_CNT_VALUE_LSB             0x17
#define RH_RF95_REG_18_MODEM_STAT                          0x18
#define RH_RF95_REG_19_PKT_SNR_VALUE                       0x19
#define RH_RF95_REG_1A_PKT_RSSI_VALUE                      0x1a
#define RH_RF95_REG_1B_RSSI_VALUE                          0x1b
#define RH_RF95_REG_1C_HOP_CHANNEL                         0x1c
#define RH_RF95_REG_1D_MODEM_CONFIG1                       0x1d
#define RH_RF95_REG_1E_MODEM_CONFIG2                       0x1e
#define RH_RF95_REG_1F_SYMB_TIMEOUT_LSB                    0x1f
#define RH_RF95_REG_20_PREAMBLE_MSB                        0x20
#define RH_RF95_REG_21_PREAMBLE_LSB                        0x21
#define RH_RF95_REG_22_PAYLOAD_LENGTH                      0x22
#define RH_RF95_REG_23_MAX_PAYLOAD_LENGTH                  0x23
#define RH_RF95_REG_24_HOP_PERIOD                          0x24
#define RH_RF95_REG_25_FIFO_RX_BYTE_ADDR                   0x25
#define RH_RF95_REG_26_MODEM_CONFIG3                       0x26

#define RH_RF95_REG_27_PPM_CORRECTION                      0x27
#define RH_RF95_REG_28_FEI_MSB                             0x28
#define RH_RF95_REG_29_FEI_MID                             0x29
#define RH_RF95_REG_2A_FEI_LSB                             0x2a
#define RH_RF95_REG_2C_RSSI_WIDEBAND                       0x2c
#define RH_RF95_REG_31_DETECT_OPTIMIZ                      0x31
#define RH_RF95_REG_33_INVERT_IQ                           0x33
#define RH_RF95_REG_37_DETECTION_THRESHOLD                 0x37
#define RH_RF95_REG_39_SYNC_WORD                           0x39

#define RH_RF95_REG_40_DIO_MAPPING1                        0x40
#define RH_RF95_REG_41_DIO_MAPPING2                        0x41
#define RH_RF95_REG_42_VERSION                             0x42

#define RH_RF95_REG_4B_TCXO                                0x4b
#define RH_RF95_REG_4D_PA_DAC                              0x4d
#define RH_RF95_REG_5B_FORMER_TEMP                         0x5b
#define RH_RF95_REG_61_AGC_REF                             0x61
#define RH_RF95_REG_62_AGC_THRESH1                         0x62
#define RH_RF95_REG_63_AGC_THRESH2                         0x63
#define RH_RF95_REG_64_AGC_THRESH3                         0x64

// RH_RF95_REG_01_OP_MODE                             0x01
#define RH_RF95_LONG_RANGE_MODE                       0x80
#define RH_RF95_ACCESS_SHARED_REG                     0x40
#define RH_RF95_LOW_FREQUENCY_MODE                    0x08
#define RH_RF95_MODE                                  0x07
#define RH_RF95_MODE_SLEEP                            0x00
#define RH_RF95_MODE_STDBY                            0x01
#define RH_RF95_MODE_FSTX                             0x02
#define RH_RF95_MODE_TX                               0x03
#define RH_RF95_MODE_FSRX                             0x04
#define RH_RF95_MODE_RXCONTINUOUS                     0x05
#define RH_RF95_MODE_RXSINGLE                         0x06
#define RH_RF95_MODE_CAD                              0x07

// RH_RF95_REG_09_PA_CONFIG                           0x09
#define RH_RF95_PA_SELECT                             0x80
#define RH_RF95_MAX_POWER                             0x70
#define RH_RF95_OUTPUT_POWER                          0x0f

// RH_RF95_REG_0A_PA_RAMP                             0x0a
#define RH_RF95_LOW_PN_TX_PLL_OFF                     0x10
#define RH_RF95_PA_RAMP                               0x0f
#define RH_RF95_PA_RAMP_3_4MS                         0x00
#define RH_RF95_PA_RAMP_2MS                           0x01
#define RH_RF95_PA_RAMP_1MS                           0x02
#define RH_RF95_PA_RAMP_500US                         0x03
#define RH_RF95_PA_RAMP_250US                         0x0
#define RH_RF95_PA_RAMP_125US                         0x05
#define RH_RF95_PA_RAMP_100US                         0x06
#define RH_RF95_PA_RAMP_62US                          0x07
#define RH_RF95_PA_RAMP_50US                          0x08
#define RH_RF95_PA_RAMP_40US                          0x09
#define RH_RF95_PA_RAMP_31US                          0x0a
#define RH_RF95_PA_RAMP_25US                          0x0b
#define RH_RF95_PA_RAMP_20US                          0x0c
#define RH_RF95_PA_RAMP_15US                          0x0d
#define RH_RF95_PA_RAMP_12US                          0x0e
#define RH_RF95_PA_RAMP_10US                          0x0f

// RH_RF95_REG_0B_OCP                                 0x0b
#define RH_RF95_OCP_ON                                0x20
#define RH_RF95_OCP_TRIM                              0x1f

// RH_RF95_REG_0C_LNA                                 0x0c
#define RH_RF95_LNA_GAIN                              0xe0
#define RH_RF95_LNA_GAIN_G1                           0x20
#define RH_RF95_LNA_GAIN_G2                           0x40
#define RH_RF95_LNA_GAIN_G3                           0x60                
#define RH_RF95_LNA_GAIN_G4                           0x80
#define RH_RF95_LNA_GAIN_G5                           0xa0
#define RH_RF95_LNA_GAIN_G6                           0xc0
#define RH_RF95_LNA_BOOST_LF                          0x18
#define RH_RF95_LNA_BOOST_LF_DEFAULT                  0x00
#define RH_RF95_LNA_BOOST_HF                          0x03
#define RH_RF95_LNA_BOOST_HF_DEFAULT                  0x00
#define RH_RF95_LNA_BOOST_HF_150PC                    0x11

// RH_RF95_REG_11_IRQ_FLAGS_MASK                      0x11
#define RH_RF95_RX_TIMEOUT_MASK                       0x80
#define RH_RF95_RX_DONE_MASK                          0x40
#define RH_RF95_PAYLOAD_CRC_ERROR_MASK                0x20
#define RH_RF95_VALID_HEADER_MASK                     0x10
#define RH_RF95_TX_DONE_MASK                          0x08
#define RH_RF95_CAD_DONE_MASK                         0x04
#define RH_RF95_FHSS_CHANGE_CHANNEL_MASK              0x02
#define RH_RF95_CAD_DETECTED_MASK                     0x01

// RH_RF95_REG_12_IRQ_FLAGS                           0x12
#define RH_RF95_RX_TIMEOUT                            0x80
#define RH_RF95_RX_DONE                               0x40
#define RH_RF95_PAYLOAD_CRC_ERROR                     0x20
#define RH_RF95_VALID_HEADER                          0x10
#define RH_RF95_TX_DONE                               0x08
#define RH_RF95_CAD_DONE                              0x04
#define RH_RF95_FHSS_CHANGE_CHANNEL                   0x02
#define RH_RF95_CAD_DETECTED                          0x01

// RH_RF95_REG_18_MODEM_STAT                          0x18
#define RH_RF95_RX_CODING_RATE                        0xe0
#define RH_RF95_MODEM_STATUS_CLEAR                    0x10
#define RH_RF95_MODEM_STATUS_HEADER_INFO_VALID        0x08
#define RH_RF95_MODEM_STATUS_RX_ONGOING               0x04
#define RH_RF95_MODEM_STATUS_SIGNAL_SYNCHRONIZED      0x02
#define RH_RF95_MODEM_STATUS_SIGNAL_DETECTED          0x01

// RH_RF95_REG_1C_HOP_CHANNEL                         0x1c
#define RH_RF95_PLL_TIMEOUT                           0x80
#define RH_RF95_RX_PAYLOAD_CRC_IS_ON                  0x40
#define RH_RF95_FHSS_PRESENT_CHANNEL                  0x3f

// RH_RF95_REG_1D_MODEM_CONFIG1                       0x1d
#define RH_RF95_BW                                    0xf0

#define RH_RF95_BW_7_8KHZ                             0x00
#define RH_RF95_BW_10_4KHZ                            0x10
#define RH_RF95_BW_15_6KHZ                            0x20
#define RH_RF95_BW_20_8KHZ                            0x30
#define RH_RF95_BW_31_25KHZ                           0x40
#define RH_RF95_BW_41_7KHZ                            0x50
#define RH_RF95_BW_62_5KHZ                            0x60
#define RH_RF95_BW_125KHZ                             0x70
#define RH_RF95_BW_250KHZ                             0x80
#define RH_RF95_BW_500KHZ                             0x90
#define RH_RF95_CODING_RATE                           0x0e
#define RH_RF95_CODING_RATE_4_5                       0x02
#define RH_RF95_CODING_RATE_4_6                       0x04
#define RH_RF95_CODING_RATE_4_7                       0x06
#define RH_RF95_CODING_RATE_4_8                       0x08
#define RH_RF95_IMPLICIT_HEADER_MODE_ON               0x01

// RH_RF95_REG_1E_MODEM_CONFIG2                       0x1e
#define RH_RF95_SPREADING_FACTOR                      0xf0
#define RH_RF95_SPREADING_FACTOR_64CPS                0x60
#define RH_RF95_SPREADING_FACTOR_128CPS               0x70
#define RH_RF95_SPREADING_FACTOR_256CPS               0x80
#define RH_RF95_SPREADING_FACTOR_512CPS               0x90
#define RH_RF95_SPREADING_FACTOR_1024CPS              0xa0
#define RH_RF95_SPREADING_FACTOR_2048CPS              0xb0
#define RH_RF95_SPREADING_FACTOR_4096CPS              0xc0
#define RH_RF95_TX_CONTINUOUS_MOE                     0x08

#define RH_RF95_PAYLOAD_CRC_ON                        0x04
#define RH_RF95_SYM_TIMEOUT_MSB                       0x03

// RH_RF95_REG_4B_TCXO                                0x4b
#define RH_RF95_TCXO_TCXO_INPUT_ON                    0x10

// RH_RF95_REG_4D_PA_DAC                              0x4d
#define RH_RF95_PA_DAC_DISABLE                        0x04
#define RH_RF95_PA_DAC_ENABLE                         0x07

/////////////////////////////////////////////////////////////////////
/// \class RH_RF95 RH_RF95.h <RH_RF95.h>
/// \brief Driver to send and receive unaddressed, unreliable datagrams via a LoRa 
/// capable radio transceiver.
///
/// For Semtech SX1276/77/78/79 and HopeRF RF95/96/97/98 and other similar LoRa capable radios.
/// Based on http://www.hoperf.com/upload/rf/RFM95_96_97_98W.pdf
/// and http://www.hoperf.cn/upload/rfchip/RF96_97_98.pdf
/// and http://www.semtech.com/images/datasheet/LoraDesignGuide_STD.pdf
/// and http://www.semtech.com/images/datasheet/sx1276.pdf
/// and http://www.semtech.com/images/datasheet/sx1276_77_78_79.pdf
/// FSK/GFSK/OOK modes are not (yet) supported.
///
/// Works with
/// - the excellent MiniWirelessLoRa from Anarduino http://www.anarduino.com/miniwireless
/// - The excellent Modtronix inAir4 http://modtronix.com/inair4.html 
/// and inAir9 modules http://modtronix.com/inair9.html.
/// - the excellent Rocket Scream Mini Ultra Pro with the RFM95W 
///   http://www.rocketscream.com/blog/product/mini-ultra-pro-with-radio/
/// - Lora1276 module from NiceRF http://www.nicerf.com/product_view.aspx?id=99
/// - Adafruit Feather M0 with RFM95 
///
/// \par Overview
///
/// This class provides basic functions for sending and receiving unaddressed, 
/// unreliable datagrams of arbitrary length to 251 octets per packet.
///
/// Manager classes may use this class to implement reliable, addressed datagrams and streams, 
/// mesh routers, repeaters, translators etc.
///
/// Naturally, for any 2 radios to communicate that must be configured to use the same frequency and 
/// modulation scheme.
///
/// This Driver provides an object-oriented interface for sending and receiving data messages with Hope-RF
/// RFM95/96/97/98(W), Semtech SX1276/77/78/79 and compatible radio modules in LoRa mode.
///
/// The Hope-RF (http://www.hoperf.com) RFM95/96/97/98(W) and Semtech SX1276/77/78/79 is a low-cost ISM transceiver
/// chip. It supports FSK, GFSK, OOK over a wide range of frequencies and
/// programmable data rates, and it also supports the proprietary LoRA (Long Range) mode, which
/// is the only mode supported in this RadioHead driver.
///
/// This Driver provides functions for sending and receiving messages of up
/// to 251 octets on any frequency supported by the radio, in a range of
/// predefined Bandwidths, Spreading Factors and Coding Rates.  Frequency can be set with
/// 61Hz precision to any frequency from 240.0MHz to 960.0MHz. Caution: most modules only support a more limited
/// range of frequencies due to antenna tuning.
///
/// Up to 2 modules can be connected to an Arduino (3 on a Mega),
/// permitting the construction of translators and frequency changers, etc.
///
/// Support for other features such as transmitter power control etc is
/// also provided.
///
/// Tested on MinWirelessLoRa with arduino-1.0.5
/// on OpenSuSE 13.1. 
/// Also tested with Teensy3.1, Modtronix inAir4 and Arduino 1.6.5 on OpenSuSE 13.1
///
/// \par Packet Format
///
/// All messages sent and received by this RH_RF95 Driver conform to this packet format:
///
/// - LoRa mode:
/// - 8 symbol PREAMBLE
/// - Explicit header with header CRC (handled internally by the radio)
/// - 4 octets HEADER: (TO, FROM, ID, FLAGS)
/// - 0 to 251 octets DATA 
/// - CRC (handled internally by the radio)
///
/// \par Connecting RFM95/96/97/98 and Semtech SX1276/77/78/79 to Arduino
///
/// We tested with Anarduino MiniWirelessLoRA, which is an Arduino Duemilanove compatible with a RFM96W
/// module on-board. Therefore it needs no connections other than the USB
/// programming connection and an antenna to make it work.
///
/// If you have a bare RFM95/96/97/98 that you want to connect to an Arduino, you
/// might use these connections (untested): CAUTION: you must use a 3.3V type
/// Arduino, otherwise you will also need voltage level shifters between the
/// Arduino and the RFM95.  CAUTION, you must also ensure you connect an
/// antenna.
/// 
/// \code
///                 Arduino      RFM95/96/97/98
///                 GND----------GND   (ground in)
///                 3V3----------3.3V  (3.3V in)
/// interrupt 0 pin D2-----------DIO0  (interrupt request out)
///          SS pin D10----------NSS   (CS chip select in)
///         SCK pin D13----------SCK   (SPI clock in)
///        MOSI pin D11----------MOSI  (SPI Data in)
///        MISO pin D12----------MISO  (SPI Data out)
/// \endcode
/// With these connections, you can then use the default constructor RH_RF95().
/// You can override the default settings for the SS pin and the interrupt in
/// the RH_RF95 constructor if you wish to connect the slave select SS to other
/// than the normal one for your Arduino (D10 for Diecimila, Uno etc and D53
/// for Mega) or the interrupt request to other than pin D2 (Caution,
/// different processors have different constraints as to the pins available
/// for interrupts).
///
/// You can connect a Modtronix inAir4 or inAir9 directly to a 3.3V part such as a Teensy 3.1 like
/// this (tested).
/// \code
///                 Teensy      inAir4 inAir9
///                 GND----------GND   (ground in)
///                 3V3----------3.3V  (3.3V in)
/// interrupt 0 pin D2-----------D00   (interrupt request out)
///          SS pin D10----------CS    (CS chip select in)
///         SCK pin D13----------CK    (SPI clock in)
///        MOSI pin D11----------SI    (SPI Data in)
///        MISO pin D12----------SO    (SPI Data out)
/// \endcode
/// With these connections, you can then use the default constructor RH_RF95().
/// you must also set the transmitter power with useRFO:
/// driver.setTxPower(13, true);
///
/// Note that if you are using Modtronix inAir4 or inAir9,or any other module which uses the
/// transmitter RFO pins and not the PA_BOOST pins
/// that you must configure the power transmitter power for -1 to 14 dBm and with useRFO true. 
/// Failure to do that will result in extremely low transmit powers.
///
/// If you have an Arduino M0 Pro from arduino.org, 
/// you should note that you cannot use Pin 2 for the interrupt line 
/// (Pin 2 is for the NMI only). The same comments apply to Pin 4 on Arduino Zero from arduino.cc.
/// Instead you can use any other pin (we use Pin 3) and initialise RH_RF69 like this:
/// \code
/// // Slave Select is pin 10, interrupt is Pin 3
/// RH_RF95 driver(10, 3);
/// \endcode
///
/// If you have a Rocket Scream Mini Ultra Pro with the RFM95W:
/// - Ensure you have Arduino SAMD board support 1.6.5 or later in Arduino IDE 1.6.8 or later.
/// - The radio SS is hardwired to pin D5 and the DIO0 interrupt to pin D2, 
/// so you need to initialise the radio like this:
/// \code
/// RH_RF95 driver(5, 2);
/// \endcode
/// - The name of the serial port on that board is 'SerialUSB', not 'Serial', so this may be helpful at the top of our
///   sample sketches:
/// \code
/// #define Serial SerialUSB
/// \endcode
/// - You also need this in setup before radio initialisation  
/// \code
/// // Ensure serial flash is not interfering with radio communication on SPI bus
///  pinMode(4, OUTPUT);
///  digitalWrite(4, HIGH);
/// \endcode
/// - and if you have a 915MHz part, you need this after driver/manager intitalisation:
/// \code
/// rf95.setFrequency(915.0);
/// \endcode
/// which adds up to modifying sample sketches something like:
/// \code
/// #include <SPI.h>
/// #include <RH_RF95.h>
/// RH_RF95 rf95(5, 2); // Rocket Scream Mini Ultra Pro with the RFM95W
/// #define Serial SerialUSB
/// 
/// void setup() 
/// {
///   // Ensure serial flash is not interfering with radio communication on SPI bus
///   pinMode(4, OUTPUT);
///   digitalWrite(4, HIGH);
/// 
///   Serial.begin(9600);
///   while (!Serial) ; // Wait for serial port to be available
///   if (!rf95.init())
///     Serial.println("init failed");
///   rf95.setFrequency(915.0);
/// }
/// ...
/// \endcode
///
/// For Adafruit Feather M0 with RFM95, construct the driver like this:
/// \code
/// RH_RF95 rf95(8, 3);
/// \endcode
///
/// It is possible to have 2 or more radios connected to one Arduino, provided
/// each radio has its own SS and interrupt line (SCK, SDI and SDO are common
/// to all radios)
///
/// Caution: on some Arduinos such as the Mega 2560, if you set the slave
/// select pin to be other than the usual SS pin (D53 on Mega 2560), you may
/// need to set the usual SS pin to be an output to force the Arduino into SPI
/// master mode.
///
/// Caution: Power supply requirements of the RFM module may be relevant in some circumstances: 
/// RFM95/96/97/98 modules are capable of pulling 120mA+ at full power, where Arduino's 3.3V line can
/// give 50mA. You may need to make provision for alternate power supply for
/// the RFM module, especially if you wish to use full transmit power, and/or you have
/// other shields demanding power. Inadequate power for the RFM is likely to cause symptoms such as:
/// - reset's/bootups terminate with "init failed" messages
/// - random termination of communication after 5-30 packets sent/received
/// - "fake ok" state, where initialization passes fluently, but communication doesn't happen
/// - shields hang Arduino boards, especially during the flashing
///
/// \par Interrupts
///
/// The RH_RF95 driver uses interrupts to react to events in the RFM module,
/// such as the reception of a new packet, or the completion of transmission
/// of a packet.  The RH_RF95 driver interrupt service routine reads status from
/// and writes data to the the RFM module via the SPI interface. It is very
/// important therefore, that if you are using the RH_RF95 driver with another
/// SPI based deviced, that you disable interrupts while you transfer data to
/// and from that other device.  Use cli() to disable interrupts and sei() to
/// reenable them.
///
/// \par Memory
///
/// The RH_RF95 driver requires non-trivial amounts of memory. The sample
/// programs all compile to about 8kbytes each, which will fit in the
/// flash proram memory of most Arduinos. However, the RAM requirements are
/// more critical. Therefore, you should be vary sparing with RAM use in
/// programs that use the RH_RF95 driver.
///
/// It is often hard to accurately identify when you are hitting RAM limits on Arduino. 
/// The symptoms can include:
/// - Mysterious crashes and restarts
/// - Changes in behaviour when seemingly unrelated changes are made (such as adding print() statements)
/// - Hanging
/// - Output from Serial.print() not appearing
///
/// \par Range
///
/// We have made some simple range tests under the following conditions:
/// - rf95_client base station connected to a VHF discone antenna at 8m height above ground
/// - rf95_server mobile connected to 17.3cm 1/4 wavelength antenna at 1m height, no ground plane.
/// - Both configured for 13dBm, 434MHz, Bw = 125 kHz, Cr = 4/8, Sf = 4096chips/symbol, CRC on. Slow+long range
/// - Minimum reported RSSI seen for successful comms was about -91
/// - Range over flat ground through heavy trees and vegetation approx 2km.
/// - At 20dBm (100mW) otherwise identical conditions approx 3km.
/// - At 20dBm, along salt water flat sandy beach, 3.2km.
///
/// It should be noted that at this data rate, a 12 octet message takes 2 seconds to transmit.
///
/// At 20dBm (100mW) with Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on. 
/// (Default medium range) in the conditions described above.
/// - Range over flat ground through heavy trees and vegetation approx 2km.
///
/// Caution: the performance of this radio, especially with narrow bandwidths is strongly dependent on the
/// accuracy and stability of the chip clock. HopeRF and Semtech do not appear to 
/// recommend bandwidths of less than 62.5 kHz 
/// unless you have the optional Temperature Compensated Crystal Oscillator (TCXO) installed and 
/// enabled on your radio module. See the refernece manual for more data.
/// Also https://lowpowerlab.com/forum/rf-range-antennas-rfm69-library/lora-library-experiences-range/15/
/// and http://www.semtech.com/images/datasheet/an120014-xo-guidance-lora-modulation.pdf
/// 
/// \par Transmitter Power
///
/// You can control the transmitter power on the RF transceiver
/// with the RH_RF95::setTxPower() function. The argument can be any of
/// +5 to +23 (for modules that use PA_BOOST)
/// -1 to +14 (for modules that use RFO transmitter pin)
/// The default is 13. Eg:
/// \code
/// driver.setTxPower(10); // use PA_BOOST transmitter pin
/// driver.setTxPower(10, true); // use PA_RFO pin transmitter pin
/// \endcode
///
/// We have made some actual power measurements against
/// programmed power for Anarduino MiniWirelessLoRa (which has RFM96W-433Mhz installed)
/// - MiniWirelessLoRa RFM96W-433Mhz, USB power
/// - 30cm RG316 soldered direct to RFM96W module ANT and GND
/// - SMA connector
/// - 12db attenuator
/// - SMA connector
/// - MiniKits AD8307 HF/VHF Power Head (calibrated against Rohde&Schwartz 806.2020 test set)
/// - Tektronix TDS220 scope to measure the Vout from power head
/// \code
/// Program power           Measured Power
///    dBm                         dBm
///      5                           5
///      7                           7
///      9                           8
///     11                          11
///     13                          13
///     15                          15
///     17                          16
///     19                          18
///     20                          20 
///     21                          21 
///     22                          22 
///     23                          23 
/// \endcode
///
/// We have also measured the actual power output from a Modtronix inAir4 http://modtronix.com/inair4.html
/// connected to a Teensy 3.1:
/// Teensy 3.1 this is a 3.3V part, connected directly to:
/// Modtronix inAir4 with SMA antenna connector, connected as above:
/// 10cm SMA-SMA cable
/// - MiniKits AD8307 HF/VHF Power Head (calibrated against Rohde&Schwartz 806.2020 test set)
/// - Tektronix TDS220 scope to measure the Vout from power head
/// \code
/// Program power           Measured Power
///    dBm                         dBm
///      -1                         0
///      1                          2
///      3                          4
///      5                          7
///      7                         10
///      9                         13
///     11                         14.2
///     13                         15
///     14                         16
/// \endcode
/// (Caution: we dont claim laboratory accuracy for these power measurements)
/// You would not expect to get anywhere near these powers to air with a simple 1/4 wavelength wire antenna.
class RH_RF95 : public RHGenericDriver
{
public:
    /// \brief Defines register values for a set of modem configuration registers
    ///
    /// Defines register values for a set of modem configuration registers
    /// that can be passed to setModemRegisters() if none of the choices in
    /// ModemConfigChoice suit your need setModemRegisters() writes the
    /// register values from this structure to the appropriate registers
    /// to set the desired spreading factor, coding rate and bandwidth
    typedef struct
    {
    uint8_t    reg_1d;   ///< Value for register RH_RF95_REG_1D_MODEM_CONFIG1
    uint8_t    reg_1e;   ///< Value for register RH_RF95_REG_1E_MODEM_CONFIG2
    uint8_t    reg_26;   ///< Value for register RH_RF95_REG_26_MODEM_CONFIG3
    } ModemConfig;
  
    /// Choices for setModemConfig() for a selected subset of common
    /// data rates. If you need another configuration,
    /// determine the necessary settings and call setModemRegisters() with your
    /// desired settings. It might be helpful to use the LoRa calculator mentioned in 
    /// http://www.semtech.com/images/datasheet/LoraDesignGuide_STD.pdf
    /// These are indexes into MODEM_CONFIG_TABLE. We strongly recommend you use these symbolic
    /// definitions and not their integer equivalents: its possible that new values will be
    /// introduced in later versions (though we will try to avoid it).
    /// Caution: if you are using slow packet rates and long packets with RHReliableDatagram or subclasses
    /// you may need to change the RHReliableDatagram timeout for reliable operations.
    /// Caution: for some slow rates nad with ReliableDatagrams youi may need to increase the reply timeout 
    /// with manager.setTimeout() to
    /// deal with the long transmission times.
    typedef enum
    {
    Bw125Cr45Sf128 = 0,    ///< Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on. Default medium range
    Bw500Cr45Sf128,            ///< Bw = 500 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on. Fast+short range
    Bw31_25Cr48Sf512,      ///< Bw = 31.25 kHz, Cr = 4/8, Sf = 512chips/symbol, CRC on. Slow+long range
    Bw125Cr48Sf4096,           ///< Bw = 125 kHz, Cr = 4/8, Sf = 4096chips/symbol, CRC on. Slow+long range
    } ModemConfigChoice;

    /// Constructor. You can have multiple instances, but each instance must have its own
    /// interrupt and slave select pin. After constructing, you must call init() to initialise the interface
    /// and the radio module. A maximum of 3 instances can co-exist on one processor, provided there are sufficient
    /// distinct interrupt lines, one for each instance.
    /// \param[in] slaveSelectPin the Arduino pin number of the output to use to select the RH_RF22 before
    /// accessing it. Defaults to the normal SS pin for your Arduino (D10 for Diecimila, Uno etc, D53 for Mega, D10 for Maple)
    /// \param[in] interruptPin The interrupt Pin number that is connected to the RFM DIO0 interrupt line. 
    /// Defaults to pin 2, as required by Anarduino MinWirelessLoRa module.
    /// Caution: You must specify an interrupt capable pin.
    /// On many Arduino boards, there are limitations as to which pins may be used as interrupts.
    /// On Leonardo pins 0, 1, 2 or 3. On Mega2560 pins 2, 3, 18, 19, 20, 21. On Due and Teensy, any digital pin.
    /// On Arduino Zero from arduino.cc, any digital pin other than 4.
    /// On Arduino M0 Pro from arduino.org, any digital pin other than 2.
    /// On other Arduinos pins 2 or 3. 
    /// See http://arduino.cc/en/Reference/attachInterrupt for more details.
    /// On Chipkit Uno32, pins 38, 2, 7, 8, 35.
    /// On other boards, any digital pin may be used.
    /// \param[in] spi Pointer to the SPI interface object to use. 
    /// \param[in] ssNum the swspi slave select number to use
    RH_RF95(swspi& spi, int ssNum);
  
    /// Initialise the Driver transport hardware and software.
    /// Make sure the Driver is properly configured before calling init().
    /// \return true if initialisation succeeded.
    virtual bool    init();

    /// Prints the value of all chip registers
    /// to the Serial device if RH_HAVE_SERIAL is defined for the current platform
    /// For debugging purposes only.
    /// \return true on success
    bool printRegisters();

    /// Sets all the registered required to configure the data modem in the RF95/96/97/98, including the bandwidth, 
    /// spreading factor etc. You can use this to configure the modem with custom configurations if none of the 
    /// canned configurations in ModemConfigChoice suit you.
    /// \param[in] config A ModemConfig structure containing values for the modem configuration registers.
    void           setModemRegisters(const ModemConfig* config);

    /// Select one of the predefined modem configurations. If you need a modem configuration not provided 
    /// here, use setModemRegisters() with your own ModemConfig.
    /// \param[in] index The configuration choice.
    /// \return true if index is a valid choice.
    bool        setModemConfig(ModemConfigChoice index);

    /// Tests whether a new message is available
    /// from the Driver. 
    /// On most drivers, this will also put the Driver into RHModeRx mode until
    /// a message is actually received by the transport, when it wil be returned to RHModeIdle.
    /// This can be called multiple times in a timeout loop
    /// \return true if a new, complete, error-free uncollected message is available to be retreived by recv()
    virtual bool    available();

    /// Turns the receiver on if it not already on.
    /// If there is a valid message available, copy it to buf and return true
    /// else return false.
    /// If a message is copied, *len is set to the length (Caution, 0 length messages are permitted).
    /// You should be sure to call this function frequently enough to not miss any messages
    /// It is recommended that you call it in your main loop.
    /// \param[in] buf Location to copy the received message
    /// \param[in,out] len Pointer to available space in buf. Set to the actual number of octets copied.
    /// \return true if a valid message was copied to buf
    virtual bool    recv(uint8_t* buf, uint8_t* len);

    /// Waits until any previous transmit packet is finished being transmitted with waitPacketSent().
    /// Then optionally waits for Channel Activity Detection (CAD) 
    /// to show the channnel is clear (if the radio supports CAD) by calling waitCAD().
    /// Then loads a message into the transmitter and starts the transmitter. Note that a message length
    /// of 0 is permitted. 
    /// \param[in] data Array of data to be sent
    /// \param[in] len Number of bytes of data to send
    /// specify the maximum time in ms to wait. If 0 (the default) do not wait for CAD before transmitting.
    /// \return true if the message length was valid and it was correctly queued for transmit. Return false
    /// if CAD was requested and the CAD timeout timed out before clear channel was detected.
    virtual bool    send(const uint8_t* data, uint8_t len);

    /// Sets the length of the preamble
    /// in bytes. 
    /// Caution: this should be set to the same 
    /// value on all nodes in your network. Default is 8.
    /// Sets the message preamble length in RH_RF95_REG_??_PREAMBLE_?SB
    /// \param[in] bytes Preamble length in bytes.  
    void           setPreambleLength(uint16_t bytes);

    /// Returns the maximum message length 
    /// available in this Driver.
    /// \return The maximum legal message length
    virtual uint8_t maxMessageLength();

    /// Sets the transmitter and receiver 
    /// centre frequency.
    /// \param[in] centre Frequency in MHz. 137.0 to 1020.0. Caution: RFM95/96/97/98 comes in several
    /// different frequency ranges, and setting a frequency outside that range of your radio will probably not work
    /// \return true if the selected frquency centre is within range
    bool        setFrequency(float centre);

    /// If current mode is Rx or Tx changes it to Idle. If the transmitter or receiver is running, 
    /// disables them.
    void           setModeIdle();

    /// If current mode is Tx or Idle, changes it to Rx. 
    /// Starts the receiver in the RF95/96/97/98.
    void           setModeRx();

    /// If current mode is Rx or Idle, changes it to Rx. F
    /// Starts the transmitter in the RF95/96/97/98.
    void           setModeTx();

    /// Sets the transmitter power output level, and configures the transmitter pin.
    /// Be a good neighbour and set the lowest power level you need.
    /// Some SX1276/77/78/79 and compatible modules (such as RFM95/96/97/98) 
    /// use the PA_BOOST transmitter pin for high power output (and optionally the PA_DAC)
    /// while some (such as the Modtronix inAir4 and inAir9) 
    /// use the RFO transmitter pin for lower power but higher efficiency.
    /// You must set the appropriate power level and useRFO argument for your module.
    /// Check with your module manufacturer which transmtter pin is used on your module
    /// to ensure you are setting useRFO correctly. 
    /// Failure to do so will result in very low 
    /// transmitter power output.
    /// Caution: legal power limits may apply in certain countries.
    /// After init(), the power will be set to 13dBm, with useRFO false (ie PA_BOOST enabled).
    /// \param[in] power Transmitter power level in dBm. For RFM95/96/97/98 LORA with useRFO false, 
    /// valid values are from +5 to +23.
    /// For Modtronix inAir4 and inAir9 with useRFO true (ie RFO pins in use), 
    /// valid values are from -1 to 14.
    /// \param[in] useRFO If true, enables the use of the RFO transmitter pins instead of
    /// the PA_BOOST pin (false). Choose the correct setting for your module.
    void           setTxPower(int8_t power, bool useRFO = false);

    /// Sets the radio into low-power sleep mode.
    /// If successful, the transport will stay in sleep mode until woken by 
    /// changing mode it idle, transmit or receive (eg by calling send(), recv(), available() etc)
    /// Caution: there is a time penalty as the radio takes a finite time to wake from sleep mode.
    /// \return true if sleep mode was successfully entered.
    virtual bool    sleep();

    // Bent G Christensen (bentor@gmail.com), 08/15/2016
    /// Use the radio's Channel Activity Detect (CAD) function to detect channel activity.
    /// Sets the RF95 radio into CAD mode and waits until CAD detection is complete.
    /// To be used in a listen-before-talk mechanism (Collision Avoidance)
    /// with a reasonable time backoff algorithm.
    /// This is called automatically by waitCAD().
    /// \return true if channel is in use.  
    virtual bool    isChannelActive();

    /// Enable TCXO mode
    /// Call this immediately after init(), to force your radio to use an external 
    /// frequency source, such as a Temperature Compensated Crystal Oscillator (TCXO).
    /// See the comments in the main documentation about the sensitivity of this radio to
    /// clock frequency especially when using narrow bandwidths.
    /// Leaves the module in sleep mode.
    /// Caution, this function has not been tested by us.
    void enableTCXO();

    /// Returns the last measured frequency error.
    /// The LoRa receiver estimates the frequency offset between the receiver centre frequency
    /// and that of the received LoRa signal. This function returns the estimates offset (in Hz) 
    /// of the last received message. Caution: this measurement is not absolute, but is measured 
    /// relative to the local receiver's oscillator. 
    /// Apparent errors may be due to the transmitter, the receiver or both.
    /// \return The estimated centre frequency offset in Hz of the last received message. 
    /// If the modem bandwidth selector in 
    /// register RH_RF95_REG_1D_MODEM_CONFIG1 is invalid, returns 0.
    int frequencyError();

    /// Returns the Signal-to-noise ratio (SNR) of the last received message, as measured
    /// by the receiver.
    /// \return SNR of the last received message in dB
    int lastSNR();

    /// This is a low level function to handle the interrupts for one instance of RH_RF95.
    /// Must be called from user code in mbed because the swspi library mutex cannot be
    /// executed in an ISR.  It should be executed when the ISR pin is seen low.
    void           handleInterrupt();

protected:
    /// Examine the revceive buffer to determine whether the message is for this node
    void validateRxBuf();

    /// Clear our local receive buffer
    void clearRxBuf();

private:
    /// SPI
    swspi&              _spi;
    int                 _ssn;
    
    /// Number of octets in the buffer
    volatile uint8_t    _bufLen;
    
    /// The receiver/transmitter buffer
    uint8_t             _buf[RH_RF95_MAX_PAYLOAD_LEN];

    /// True when there is a valid message in the buffer
    volatile bool       _rxBufValid;

    // True if we are using the HF port (779.0 MHz and above)
    bool                _usingHFport;

    // Last measured SNR, dB
    int8_t              _lastSNR;
};

/// @example rf95_client.pde
/// @example rf95_server.pde
/// @example rf95_reliable_datagram_client.pde
/// @example rf95_reliable_datagram_server.pde

#endif