Diff: RH_RF22.cpp

Revision:

0:ab4e012489ef

diff -r 000000000000 -r ab4e012489ef RH_RF22.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/RH_RF22.cpp	Thu Oct 15 01:27:00 2015 +0000
@@ -0,0 +1,748 @@
+// RH_RF22.cpp
+//
+// Copyright (C) 2011 Mike McCauley
+// $Id: RH_RF22.cpp,v 1.24 2015/05/17 00:11:26 mikem Exp $
+
+#include <RH_RF22.h>
+
+// Interrupt vectors for the 2 Arduino interrupt pins
+// Each interrupt can be handled by a different instance of RH_RF22, allowing you to have
+// 2 RH_RF22s per Arduino
+RH_RF22* RH_RF22::_deviceForInterrupt[RH_RF22_NUM_INTERRUPTS] = {0, 0, 0};
+uint8_t RH_RF22::_interruptCount = 0; // Index into _deviceForInterrupt for next device
+
+// These are indexed by the values of ModemConfigChoice
+// Canned modem configurations generated with 
+// http://www.hoperf.com/upload/rf/RH_RF22B%2023B%2031B%2042B%2043B%20Register%20Settings_RevB1-v5.xls
+// Stored in flash (program) memory to save SRAM
+PROGMEM static const RH_RF22::ModemConfig MODEM_CONFIG_TABLE[] =
+{
+    { 0x2b, 0x03, 0xf4, 0x20, 0x41, 0x89, 0x00, 0x36, 0x40, 0x0a, 0x1d, 0x80, 0x60, 0x10, 0x62, 0x2c, 0x00, 0x08 }, // Unmodulated carrier
+    { 0x2b, 0x03, 0xf4, 0x20, 0x41, 0x89, 0x00, 0x36, 0x40, 0x0a, 0x1d, 0x80, 0x60, 0x10, 0x62, 0x2c, 0x33, 0x08 }, // FSK, PN9 random modulation, 2, 5
+
+    // All the following enable FIFO with reg 71
+    //  1c,   1f,   20,   21,   22,   23,   24,   25,   2c,   2d,   2e,   58,   69,   6e,   6f,   70,   71,   72
+    // FSK, No Manchester, Max Rb err <1%, Xtal Tol 20ppm
+    { 0x2b, 0x03, 0xf4, 0x20, 0x41, 0x89, 0x00, 0x36, 0x40, 0x0a, 0x1d, 0x80, 0x60, 0x10, 0x62, 0x2c, 0x22, 0x08 }, // 2, 5
+    { 0x1b, 0x03, 0x41, 0x60, 0x27, 0x52, 0x00, 0x07, 0x40, 0x0a, 0x1e, 0x80, 0x60, 0x13, 0xa9, 0x2c, 0x22, 0x3a }, // 2.4, 36
+    { 0x1d, 0x03, 0xa1, 0x20, 0x4e, 0xa5, 0x00, 0x13, 0x40, 0x0a, 0x1e, 0x80, 0x60, 0x27, 0x52, 0x2c, 0x22, 0x48 }, // 4.8, 45
+    { 0x1e, 0x03, 0xd0, 0x00, 0x9d, 0x49, 0x00, 0x45, 0x40, 0x0a, 0x20, 0x80, 0x60, 0x4e, 0xa5, 0x2c, 0x22, 0x48 }, // 9.6, 45
+    { 0x2b, 0x03, 0x34, 0x02, 0x75, 0x25, 0x07, 0xff, 0x40, 0x0a, 0x1b, 0x80, 0x60, 0x9d, 0x49, 0x2c, 0x22, 0x0f }, // 19.2, 9.6
+    { 0x02, 0x03, 0x68, 0x01, 0x3a, 0x93, 0x04, 0xd5, 0x40, 0x0a, 0x1e, 0x80, 0x60, 0x09, 0xd5, 0x0c, 0x22, 0x1f }, // 38.4, 19.6
+    { 0x06, 0x03, 0x45, 0x01, 0xd7, 0xdc, 0x07, 0x6e, 0x40, 0x0a, 0x2d, 0x80, 0x60, 0x0e, 0xbf, 0x0c, 0x22, 0x2e }, // 57.6. 28.8
+    { 0x8a, 0x03, 0x60, 0x01, 0x55, 0x55, 0x02, 0xad, 0x40, 0x0a, 0x50, 0x80, 0x60, 0x20, 0x00, 0x0c, 0x22, 0xc8 }, // 125, 125
+
+    { 0x2b, 0x03, 0xa1, 0xe0, 0x10, 0xc7, 0x00, 0x09, 0x40, 0x0a, 0x1d,  0x80, 0x60, 0x04, 0x32, 0x2c, 0x22, 0x04 }, // 512 baud, FSK, 2.5 Khz fd for POCSAG compatibility
+    { 0x27, 0x03, 0xa1, 0xe0, 0x10, 0xc7, 0x00, 0x06, 0x40, 0x0a, 0x1d,  0x80, 0x60, 0x04, 0x32, 0x2c, 0x22, 0x07 }, // 512 baud, FSK, 4.5 Khz fd for POCSAG compatibility
+
+    // GFSK, No Manchester, Max Rb err <1%, Xtal Tol 20ppm
+    // These differ from FSK only in register 71, for the modulation type
+    { 0x2b, 0x03, 0xf4, 0x20, 0x41, 0x89, 0x00, 0x36, 0x40, 0x0a, 0x1d, 0x80, 0x60, 0x10, 0x62, 0x2c, 0x23, 0x08 }, // 2, 5
+    { 0x1b, 0x03, 0x41, 0x60, 0x27, 0x52, 0x00, 0x07, 0x40, 0x0a, 0x1e, 0x80, 0x60, 0x13, 0xa9, 0x2c, 0x23, 0x3a }, // 2.4, 36
+    { 0x1d, 0x03, 0xa1, 0x20, 0x4e, 0xa5, 0x00, 0x13, 0x40, 0x0a, 0x1e, 0x80, 0x60, 0x27, 0x52, 0x2c, 0x23, 0x48 }, // 4.8, 45
+    { 0x1e, 0x03, 0xd0, 0x00, 0x9d, 0x49, 0x00, 0x45, 0x40, 0x0a, 0x20, 0x80, 0x60, 0x4e, 0xa5, 0x2c, 0x23, 0x48 }, // 9.6, 45
+    { 0x2b, 0x03, 0x34, 0x02, 0x75, 0x25, 0x07, 0xff, 0x40, 0x0a, 0x1b, 0x80, 0x60, 0x9d, 0x49, 0x2c, 0x23, 0x0f }, // 19.2, 9.6
+    { 0x02, 0x03, 0x68, 0x01, 0x3a, 0x93, 0x04, 0xd5, 0x40, 0x0a, 0x1e, 0x80, 0x60, 0x09, 0xd5, 0x0c, 0x23, 0x1f }, // 38.4, 19.6
+    { 0x06, 0x03, 0x45, 0x01, 0xd7, 0xdc, 0x07, 0x6e, 0x40, 0x0a, 0x2d, 0x80, 0x60, 0x0e, 0xbf, 0x0c, 0x23, 0x2e }, // 57.6. 28.8
+    { 0x8a, 0x03, 0x60, 0x01, 0x55, 0x55, 0x02, 0xad, 0x40, 0x0a, 0x50, 0x80, 0x60, 0x20, 0x00, 0x0c, 0x23, 0xc8 }, // 125, 125
+
+    // OOK, No Manchester, Max Rb err <1%, Xtal Tol 20ppm
+    { 0x51, 0x03, 0x68, 0x00, 0x3a, 0x93, 0x01, 0x3d, 0x2c, 0x11, 0x28, 0x80, 0x60, 0x09, 0xd5, 0x2c, 0x21, 0x08 }, // 1.2, 75
+    { 0xc8, 0x03, 0x39, 0x20, 0x68, 0xdc, 0x00, 0x6b, 0x2a, 0x08, 0x2a, 0x80, 0x60, 0x13, 0xa9, 0x2c, 0x21, 0x08 }, // 2.4, 335
+    { 0xc8, 0x03, 0x9c, 0x00, 0xd1, 0xb7, 0x00, 0xd4, 0x29, 0x04, 0x29, 0x80, 0x60, 0x27, 0x52, 0x2c, 0x21, 0x08 }, // 4.8, 335
+    { 0xb8, 0x03, 0x9c, 0x00, 0xd1, 0xb7, 0x00, 0xd4, 0x28, 0x82, 0x29, 0x80, 0x60, 0x4e, 0xa5, 0x2c, 0x21, 0x08 }, // 9.6, 335
+    { 0xa8, 0x03, 0x9c, 0x00, 0xd1, 0xb7, 0x00, 0xd4, 0x28, 0x41, 0x29, 0x80, 0x60, 0x9d, 0x49, 0x2c, 0x21, 0x08 }, // 19.2, 335
+    { 0x98, 0x03, 0x9c, 0x00, 0xd1, 0xb7, 0x00, 0xd4, 0x28, 0x20, 0x29, 0x80, 0x60, 0x09, 0xd5, 0x0c, 0x21, 0x08 }, // 38.4, 335
+    { 0x98, 0x03, 0x96, 0x00, 0xda, 0x74, 0x00, 0xdc, 0x28, 0x1f, 0x29, 0x80, 0x60, 0x0a, 0x3d, 0x0c, 0x21, 0x08 }, // 40, 335
+};
+
+RH_RF22::RH_RF22(PINS slaveSelectPin, PINS interruptPin, RHGenericSPI& spi)
+    :
+    RHSPIDriver(slaveSelectPin, spi),
+    _interruptPin(interruptPin)
+{
+    _idleMode = RH_RF22_XTON; // Default idle state is READY mode
+    _polynomial = CRC_16_IBM; // Historical
+    _myInterruptIndex = 0xff; // Not allocated yet
+}
+
+void RH_RF22::setIdleMode(uint8_t idleMode)
+{
+    _idleMode = idleMode;
+}
+
+bool RH_RF22::init()
+{
+    if (!RHSPIDriver::init())
+	return false;
+
+#if (RH_PLATFORM != RH_PLATFORM_MBED)
+    // Determine the interrupt number that corresponds to the interruptPin
+    int interruptNumber = digitalPinToInterrupt(_interruptPin);
+    if (interruptNumber == NOT_AN_INTERRUPT)
+	return false;
+#endif
+
+    // Software reset the device
+    reset();
+
+    // Get the device type and check it
+    // This also tests whether we are really connected to a device
+    _deviceType = spiRead(RH_RF22_REG_00_DEVICE_TYPE);
+    if (   _deviceType != RH_RF22_DEVICE_TYPE_RX_TRX
+        && _deviceType != RH_RF22_DEVICE_TYPE_TX)
+    {
+	return false;
+    }
+
+
+#if (RH_PLATFORM != RH_PLATFORM_MBED)
+    // Add by Adrien van den Bossche <vandenbo@univ-tlse2.fr> for Teensy
+    // ARM M4 requires the below. else pin interrupt doesn't work properly.
+    // On all other platforms, its innocuous, belt and braces
+    pinMode(_interruptPin, INPUT); 
+#endif
+
+    // Enable interrupt output on the radio. Interrupt line will now go high until
+    // an interrupt occurs
+    spiWrite(RH_RF22_REG_05_INTERRUPT_ENABLE1, RH_RF22_ENTXFFAEM | RH_RF22_ENRXFFAFULL | RH_RF22_ENPKSENT | RH_RF22_ENPKVALID | RH_RF22_ENCRCERROR | RH_RF22_ENFFERR);
+    spiWrite(RH_RF22_REG_06_INTERRUPT_ENABLE2, RH_RF22_ENPREAVAL);
+
+    // Set up interrupt handler
+    // Since there are a limited number of interrupt glue functions isr*() available,
+    // we can only support a limited number of devices simultaneously
+    // On some devices, notably most Arduinos, the interrupt pin passed in is actually the 
+    // interrupt number. You have to figure out the interruptnumber-to-interruptpin mapping
+    // yourself based on knowledge of what Arduino board you are running on.
+    if (_myInterruptIndex == 0xff)
+    {
+	// First run, no interrupt allocated yet
+	if (_interruptCount <= RH_RF22_NUM_INTERRUPTS)
+	    _myInterruptIndex = _interruptCount++;
+	else
+	    return false; // Too many devices, not enough interrupt vectors
+    }
+    _deviceForInterrupt[_myInterruptIndex] = this;
+    
+#if (RH_PLATFORM == RH_PLATFORM_MBED)
+    if (_myInterruptIndex == 0)
+		_interruptPin.fall(&isr0);
+    else if (_myInterruptIndex == 1)
+		_interruptPin.fall(&isr1);
+    else if (_myInterruptIndex == 2)
+		_interruptPin.fall(&isr2);
+    else
+	return false; // Too many devices, not enough interrupt vectors
+#else
+    if (_myInterruptIndex == 0)
+	attachInterrupt(interruptNumber, isr0, FALLING);
+    else if (_myInterruptIndex == 1)
+	attachInterrupt(interruptNumber, isr1, FALLING);
+    else if (_myInterruptIndex == 2)
+	attachInterrupt(interruptNumber, isr2, FALLING);
+    else
+	return false; // Too many devices, not enough interrupt vectors
+#endif
+
+    setModeIdle();
+
+    clearTxBuf();
+    clearRxBuf();
+
+    // Most of these are the POR default
+    spiWrite(RH_RF22_REG_7D_TX_FIFO_CONTROL2, RH_RF22_TXFFAEM_THRESHOLD);
+    spiWrite(RH_RF22_REG_7E_RX_FIFO_CONTROL,  RH_RF22_RXFFAFULL_THRESHOLD);
+    spiWrite(RH_RF22_REG_30_DATA_ACCESS_CONTROL, RH_RF22_ENPACRX | RH_RF22_ENPACTX | RH_RF22_ENCRC | (_polynomial & RH_RF22_CRC));
+
+    // Configure the message headers
+    // Here we set up the standard packet format for use by the RH_RF22 library
+    // 8 nibbles preamble
+    // 2 SYNC words 2d, d4
+    // Header length 4 (to, from, id, flags)
+    // 1 octet of data length (0 to 255)
+    // 0 to 255 octets data
+    // 2 CRC octets as CRC16(IBM), computed on the header, length and data
+    // On reception the to address is check for validity against RH_RF22_REG_3F_CHECK_HEADER3
+    // or the broadcast address of 0xff
+    // If no changes are made after this, the transmitted
+    // to address will be 0xff, the from address will be 0xff
+    // and all such messages will be accepted. This permits the out-of the box
+    // RH_RF22 config to act as an unaddresed, unreliable datagram service
+    spiWrite(RH_RF22_REG_32_HEADER_CONTROL1, RH_RF22_BCEN_HEADER3 | RH_RF22_HDCH_HEADER3);
+    spiWrite(RH_RF22_REG_33_HEADER_CONTROL2, RH_RF22_HDLEN_4 | RH_RF22_SYNCLEN_2);
+
+    setPreambleLength(8);
+    uint8_t syncwords[] = { 0x2d, 0xd4 };
+    setSyncWords(syncwords, sizeof(syncwords));
+    setPromiscuous(false); 
+
+    // Set some defaults. An innocuous ISM frequency, and reasonable pull-in
+    setFrequency(434.0, 0.05);
+//    setFrequency(900.0);
+    // Some slow, reliable default speed and modulation
+    setModemConfig(FSK_Rb2_4Fd36);
+//    setModemConfig(FSK_Rb125Fd125);
+    setGpioReversed(false);
+    // Lowish power
+    setTxPower(RH_RF22_TXPOW_8DBM);
+
+    return true;
+}
+
+// C++ level interrupt handler for this instance
+void RH_RF22::handleInterrupt()
+{
+    uint8_t _lastInterruptFlags[2];
+    // Read the interrupt flags which clears the interrupt
+    spiBurstRead(RH_RF22_REG_03_INTERRUPT_STATUS1, _lastInterruptFlags, 2);
+
+#if 0
+    // DEVELOPER TESTING ONLY
+    // Caution: Serial printing in this interrupt routine can cause mysterious crashes
+    Serial.print("interrupt ");
+    Serial.print(_lastInterruptFlags[0], HEX);
+    Serial.print(" ");
+    Serial.println(_lastInterruptFlags[1], HEX);
+    if (_lastInterruptFlags[0] == 0 && _lastInterruptFlags[1] == 0)
+	Serial.println("FUNNY: no interrupt!");
+#endif
+
+#if 0
+    // DEVELOPER TESTING ONLY
+    // TESTING: fake an RH_RF22_IFFERROR
+    static int counter = 0;
+    if (_lastInterruptFlags[0] & RH_RF22_IPKSENT && counter++ == 10)
+    {
+	_lastInterruptFlags[0] = RH_RF22_IFFERROR;
+	counter = 0;
+    }
+#endif
+
+    if (_lastInterruptFlags[0] & RH_RF22_IFFERROR)
+    {
+	resetFifos(); // Clears the interrupt
+	if (_mode == RHModeTx)
+	    restartTransmit();
+	else if (_mode == RHModeRx)
+	    clearRxBuf();
+//	Serial.println("IFFERROR");  
+    }
+    // Caution, any delay here may cause a FF underflow or overflow
+    if (_lastInterruptFlags[0] & RH_RF22_ITXFFAEM)
+    {
+	// See if more data has to be loaded into the Tx FIFO 
+  	sendNextFragment();
+//	Serial.println("ITXFFAEM");  
+    }
+    if (_lastInterruptFlags[0] & RH_RF22_IRXFFAFULL)
+    {
+	// Caution, any delay here may cause a FF overflow
+	// Read some data from the Rx FIFO
+	readNextFragment();
+//	Serial.println("IRXFFAFULL"); 
+    }
+    if (_lastInterruptFlags[0] & RH_RF22_IEXT)
+    {
+	// This is not enabled by the base code, but users may want to enable it
+	handleExternalInterrupt();
+//	Serial.println("IEXT"); 
+    }
+    if (_lastInterruptFlags[1] & RH_RF22_IWUT)
+    {
+	// This is not enabled by the base code, but users may want to enable it
+	handleWakeupTimerInterrupt();
+//	Serial.println("IWUT"); 
+    }
+    if (_lastInterruptFlags[0] & RH_RF22_IPKSENT)
+    {
+//	Serial.println("IPKSENT");   
+	_txGood++; 
+	// Transmission does not automatically clear the tx buffer.
+	// Could retransmit if we wanted
+	// RH_RF22 transitions automatically to Idle
+	_mode = RHModeIdle;
+    }
+    if (_lastInterruptFlags[0] & RH_RF22_IPKVALID)
+    {
+	uint8_t len = spiRead(RH_RF22_REG_4B_RECEIVED_PACKET_LENGTH);
+//	Serial.println("IPKVALID");   
+
+	// May have already read one or more fragments
+	// Get any remaining unread octets, based on the expected length
+	// First make sure we dont overflow the buffer in the case of a stupid length
+	// or partial bad receives
+	if (   len >  RH_RF22_MAX_MESSAGE_LEN
+	    || len < _bufLen)
+	{
+	    _rxBad++;
+	    _mode = RHModeIdle;
+	    clearRxBuf();
+	    return; // Hmmm receiver buffer overflow. 
+	}
+
+	spiBurstRead(RH_RF22_REG_7F_FIFO_ACCESS, _buf + _bufLen, len - _bufLen);
+	_rxHeaderTo = spiRead(RH_RF22_REG_47_RECEIVED_HEADER3);
+	_rxHeaderFrom = spiRead(RH_RF22_REG_48_RECEIVED_HEADER2);
+	_rxHeaderId = spiRead(RH_RF22_REG_49_RECEIVED_HEADER1);
+	_rxHeaderFlags = spiRead(RH_RF22_REG_4A_RECEIVED_HEADER0);
+	_rxGood++;
+	_bufLen = len;
+	_mode = RHModeIdle;
+	_rxBufValid = true;
+    }
+    if (_lastInterruptFlags[0] & RH_RF22_ICRCERROR)
+    {
+//	Serial.println("ICRCERR");  
+	_rxBad++;
+	clearRxBuf();
+	resetRxFifo();
+	_mode = RHModeIdle;
+	setModeRx(); // Keep trying
+    }
+    if (_lastInterruptFlags[1] & RH_RF22_IPREAVAL)
+    {
+//	Serial.println("IPREAVAL");  
+	_lastRssi = (int8_t)(-120 + ((spiRead(RH_RF22_REG_26_RSSI) / 2)));
+	_lastPreambleTime = millis();
+	resetRxFifo();
+	clearRxBuf();
+    }
+}
+
+// These are low level functions that call the interrupt handler for the correct
+// instance of RH_RF22.
+// 3 interrupts allows us to have 3 different devices
+void RH_RF22::isr0()
+{
+    if (_deviceForInterrupt[0])
+	_deviceForInterrupt[0]->handleInterrupt();
+}
+void RH_RF22::isr1()
+{
+    if (_deviceForInterrupt[1])
+	_deviceForInterrupt[1]->handleInterrupt();
+}
+void RH_RF22::isr2()
+{
+    if (_deviceForInterrupt[2])
+	_deviceForInterrupt[2]->handleInterrupt();
+}
+
+void RH_RF22::reset()
+{
+    spiWrite(RH_RF22_REG_07_OPERATING_MODE1, RH_RF22_SWRES);
+    // Wait for it to settle
+    delay(1); // SWReset time is nominally 100usec
+}
+
+uint8_t RH_RF22::statusRead()
+{
+    return spiRead(RH_RF22_REG_02_DEVICE_STATUS);
+}
+
+uint8_t RH_RF22::adcRead(uint8_t adcsel,
+                      uint8_t adcref ,
+                      uint8_t adcgain, 
+                      uint8_t adcoffs)
+{
+    uint8_t configuration = adcsel | adcref | (adcgain & RH_RF22_ADCGAIN);
+    spiWrite(RH_RF22_REG_0F_ADC_CONFIGURATION, configuration | RH_RF22_ADCSTART);
+    spiWrite(RH_RF22_REG_10_ADC_SENSOR_AMP_OFFSET, adcoffs);
+
+    // Conversion time is nominally 305usec
+    // Wait for the DONE bit
+    while (!(spiRead(RH_RF22_REG_0F_ADC_CONFIGURATION) & RH_RF22_ADCDONE))
+	;
+    // Return the value  
+    return spiRead(RH_RF22_REG_11_ADC_VALUE);
+}
+
+uint8_t RH_RF22::temperatureRead(uint8_t tsrange, uint8_t tvoffs)
+{
+    spiWrite(RH_RF22_REG_12_TEMPERATURE_SENSOR_CALIBRATION, tsrange | RH_RF22_ENTSOFFS);
+    spiWrite(RH_RF22_REG_13_TEMPERATURE_VALUE_OFFSET, tvoffs);
+    return adcRead(RH_RF22_ADCSEL_INTERNAL_TEMPERATURE_SENSOR | RH_RF22_ADCREF_BANDGAP_VOLTAGE); 
+}
+
+uint16_t RH_RF22::wutRead()
+{
+    uint8_t buf[2];
+    spiBurstRead(RH_RF22_REG_17_WAKEUP_TIMER_VALUE1, buf, 2);
+    return ((uint16_t)buf[0] << 8) | buf[1]; // Dont rely on byte order
+}
+
+// RFM-22 doc appears to be wrong: WUT for wtm = 10000, r, = 0, d = 0 is about 1 sec
+void RH_RF22::setWutPeriod(uint16_t wtm, uint8_t wtr, uint8_t wtd)
+{
+    uint8_t period[3];
+
+    period[0] = ((wtr & 0xf) << 2) | (wtd & 0x3);
+    period[1] = wtm >> 8;
+    period[2] = wtm & 0xff;
+    spiBurstWrite(RH_RF22_REG_14_WAKEUP_TIMER_PERIOD1, period, sizeof(period));
+}
+
+// Returns true if centre + (fhch * fhs) is within limits
+// Caution, different versions of the RH_RF22 support different max freq
+// so YMMV
+bool RH_RF22::setFrequency(float centre, float afcPullInRange)
+{
+    uint8_t fbsel = RH_RF22_SBSEL;
+    uint8_t afclimiter;
+    if (centre < 240.0 || centre > 960.0) // 930.0 for early silicon
+	return false;
+    if (centre >= 480.0)
+    {
+	if (afcPullInRange < 0.0 || afcPullInRange > 0.318750)
+	    return false;
+	centre /= 2;
+	fbsel |= RH_RF22_HBSEL;
+	afclimiter = afcPullInRange * 1000000.0 / 1250.0;
+    }
+    else
+    {
+	if (afcPullInRange < 0.0 || afcPullInRange > 0.159375)
+	    return false;
+	afclimiter = afcPullInRange * 1000000.0 / 625.0;
+    }
+    centre /= 10.0;
+    float integerPart = floor(centre);
+    float fractionalPart = centre - integerPart;
+
+    uint8_t fb = (uint8_t)integerPart - 24; // Range 0 to 23
+    fbsel |= fb;
+    uint16_t fc = fractionalPart * 64000;
+    spiWrite(RH_RF22_REG_73_FREQUENCY_OFFSET1, 0);  // REVISIT
+    spiWrite(RH_RF22_REG_74_FREQUENCY_OFFSET2, 0);
+    spiWrite(RH_RF22_REG_75_FREQUENCY_BAND_SELECT, fbsel);
+    spiWrite(RH_RF22_REG_76_NOMINAL_CARRIER_FREQUENCY1, fc >> 8);
+    spiWrite(RH_RF22_REG_77_NOMINAL_CARRIER_FREQUENCY0, fc & 0xff);
+    spiWrite(RH_RF22_REG_2A_AFC_LIMITER, afclimiter);
+    return !(statusRead() & RH_RF22_FREQERR);
+}
+
+// Step size in 10kHz increments
+// Returns true if centre + (fhch * fhs) is within limits
+bool RH_RF22::setFHStepSize(uint8_t fhs)
+{
+    spiWrite(RH_RF22_REG_7A_FREQUENCY_HOPPING_STEP_SIZE, fhs);
+    return !(statusRead() & RH_RF22_FREQERR);
+}
+
+// Adds fhch * fhs to centre frequency
+// Returns true if centre + (fhch * fhs) is within limits
+bool RH_RF22::setFHChannel(uint8_t fhch)
+{
+    spiWrite(RH_RF22_REG_79_FREQUENCY_HOPPING_CHANNEL_SELECT, fhch);
+    return !(statusRead() & RH_RF22_FREQERR);
+}
+
+uint8_t RH_RF22::rssiRead()
+{
+    return spiRead(RH_RF22_REG_26_RSSI);
+}
+
+uint8_t RH_RF22::ezmacStatusRead()
+{
+    return spiRead(RH_RF22_REG_31_EZMAC_STATUS);
+}
+
+void RH_RF22::setOpMode(uint8_t mode)
+{
+    spiWrite(RH_RF22_REG_07_OPERATING_MODE1, mode);
+}
+
+void RH_RF22::setModeIdle()
+{
+    if (_mode != RHModeIdle)
+    {
+	setOpMode(_idleMode);
+	_mode = RHModeIdle;
+    }
+}
+
+bool RH_RF22::sleep()
+{
+    if (_mode != RHModeSleep)
+    {
+	setOpMode(0);
+	_mode = RHModeSleep;
+    }
+    return true;
+}
+
+void RH_RF22::setModeRx()
+{
+    if (_mode != RHModeRx)
+    {
+	setOpMode(_idleMode | RH_RF22_RXON);
+	_mode = RHModeRx;
+    }
+}
+
+void RH_RF22::setModeTx()
+{
+    if (_mode != RHModeTx)
+    {
+	setOpMode(_idleMode | RH_RF22_TXON);
+	// Hmmm, if you dont clear the RX FIFO here, then it appears that going
+	// to transmit mode in the middle of a receive can corrupt the
+	// RX FIFO
+	resetRxFifo();
+	_mode = RHModeTx;
+    }
+}
+
+void RH_RF22::setTxPower(uint8_t power)
+{
+    spiWrite(RH_RF22_REG_6D_TX_POWER, power | RH_RF22_LNA_SW); // On RF23, LNA_SW must be set.
+}
+
+// Sets registers from a canned modem configuration structure
+void RH_RF22::setModemRegisters(const ModemConfig* config)
+{
+    spiWrite(RH_RF22_REG_1C_IF_FILTER_BANDWIDTH,                    config->reg_1c);
+    spiWrite(RH_RF22_REG_1F_CLOCK_RECOVERY_GEARSHIFT_OVERRIDE,      config->reg_1f);
+    spiBurstWrite(RH_RF22_REG_20_CLOCK_RECOVERY_OVERSAMPLING_RATE, &config->reg_20, 6);
+    spiBurstWrite(RH_RF22_REG_2C_OOK_COUNTER_VALUE_1,              &config->reg_2c, 3);
+    spiWrite(RH_RF22_REG_58_CHARGE_PUMP_CURRENT_TRIMMING,           config->reg_58);
+    spiWrite(RH_RF22_REG_69_AGC_OVERRIDE1,                          config->reg_69);
+    spiBurstWrite(RH_RF22_REG_6E_TX_DATA_RATE1,                    &config->reg_6e, 5);
+}
+
+// Set one of the canned FSK Modem configs
+// Returns true if its a valid choice
+bool RH_RF22::setModemConfig(ModemConfigChoice index)
+{
+    if (index > (signed int)(sizeof(MODEM_CONFIG_TABLE) / sizeof(ModemConfig)))
+        return false;
+
+    RH_RF22::ModemConfig cfg;
+    memcpy_P(&cfg, &MODEM_CONFIG_TABLE[index], sizeof(RH_RF22::ModemConfig));
+    setModemRegisters(&cfg);
+
+    return true;
+}
+
+// REVISIT: top bit is in Header Control 2 0x33
+void RH_RF22::setPreambleLength(uint8_t nibbles)
+{
+    spiWrite(RH_RF22_REG_34_PREAMBLE_LENGTH, nibbles);
+}
+
+// Caution doesnt set sync word len in Header Control 2 0x33
+void RH_RF22::setSyncWords(const uint8_t* syncWords, uint8_t len)
+{
+    spiBurstWrite(RH_RF22_REG_36_SYNC_WORD3, syncWords, len);
+}
+
+void RH_RF22::clearRxBuf()
+{
+    ATOMIC_BLOCK_START;
+    _bufLen = 0;
+    _rxBufValid = false;
+    ATOMIC_BLOCK_END;
+}
+
+bool RH_RF22::available()
+{
+    if (!_rxBufValid)
+    {
+	if (_mode == RHModeTx)
+	    return false;
+	setModeRx(); // Make sure we are receiving
+    }
+    return _rxBufValid;
+}
+
+bool RH_RF22::recv(uint8_t* buf, uint8_t* len)
+{
+    if (!available())
+	return false;
+
+    if (buf && len)
+    {
+	ATOMIC_BLOCK_START;
+	if (*len > _bufLen)
+	    *len = _bufLen;
+	memcpy(buf, _buf, *len);
+	ATOMIC_BLOCK_END;
+    }
+    clearRxBuf();
+//    printBuffer("recv:", buf, *len);
+    return true;
+}
+
+void RH_RF22::clearTxBuf()
+{
+    ATOMIC_BLOCK_START;
+    _bufLen = 0;
+    _txBufSentIndex = 0;
+    ATOMIC_BLOCK_END;
+}
+
+void RH_RF22::startTransmit()
+{
+    sendNextFragment(); // Actually the first fragment
+    spiWrite(RH_RF22_REG_3E_PACKET_LENGTH, _bufLen); // Total length that will be sent
+    setModeTx(); // Start the transmitter, turns off the receiver
+}
+
+// Restart the transmission of a packet that had a problem
+void RH_RF22::restartTransmit()
+{
+    _mode = RHModeIdle;
+    _txBufSentIndex = 0;
+//	    Serial.println("Restart");
+    startTransmit();
+}
+
+bool RH_RF22::send(const uint8_t* data, uint8_t len)
+{
+    bool ret = true;
+    waitPacketSent();
+    ATOMIC_BLOCK_START;
+    spiWrite(RH_RF22_REG_3A_TRANSMIT_HEADER3, _txHeaderTo);
+    spiWrite(RH_RF22_REG_3B_TRANSMIT_HEADER2, _txHeaderFrom);
+    spiWrite(RH_RF22_REG_3C_TRANSMIT_HEADER1, _txHeaderId);
+    spiWrite(RH_RF22_REG_3D_TRANSMIT_HEADER0, _txHeaderFlags);
+    if (!fillTxBuf(data, len))
+	ret = false;
+    else
+	startTransmit();
+    ATOMIC_BLOCK_END;
+//    printBuffer("send:", data, len);
+    return ret;
+}
+
+bool RH_RF22::fillTxBuf(const uint8_t* data, uint8_t len)
+{
+    clearTxBuf();
+    if (!len)
+	return false; 
+    return appendTxBuf(data, len);
+}
+
+bool RH_RF22::appendTxBuf(const uint8_t* data, uint8_t len)
+{
+    if (((uint16_t)_bufLen + len) > RH_RF22_MAX_MESSAGE_LEN)
+	return false;
+    ATOMIC_BLOCK_START;
+    memcpy(_buf + _bufLen, data, len);
+    _bufLen += len;
+    ATOMIC_BLOCK_END;
+//    printBuffer("txbuf:", _buf, _bufLen);
+    return true;
+}
+
+// Assumption: there is currently <= RH_RF22_TXFFAEM_THRESHOLD bytes in the Tx FIFO
+void RH_RF22::sendNextFragment()
+{
+    if (_txBufSentIndex < _bufLen)
+    {
+	// Some left to send?
+	uint8_t len = _bufLen - _txBufSentIndex;
+	// But dont send too much
+	if (len > (RH_RF22_FIFO_SIZE - RH_RF22_TXFFAEM_THRESHOLD - 1))
+	    len = (RH_RF22_FIFO_SIZE - RH_RF22_TXFFAEM_THRESHOLD - 1);
+	spiBurstWrite(RH_RF22_REG_7F_FIFO_ACCESS, _buf + _txBufSentIndex, len);
+//	printBuffer("frag:", _buf  + _txBufSentIndex, len);
+	_txBufSentIndex += len;
+    }
+}
+
+// Assumption: there are at least RH_RF22_RXFFAFULL_THRESHOLD in the RX FIFO
+// That means it should only be called after a RXFFAFULL interrupt
+void RH_RF22::readNextFragment()
+{
+    if (((uint16_t)_bufLen + RH_RF22_RXFFAFULL_THRESHOLD) > RH_RF22_MAX_MESSAGE_LEN)
+	return; // Hmmm receiver overflow. Should never occur
+
+    // Read the RH_RF22_RXFFAFULL_THRESHOLD octets that should be there
+    spiBurstRead(RH_RF22_REG_7F_FIFO_ACCESS, _buf + _bufLen, RH_RF22_RXFFAFULL_THRESHOLD);
+    _bufLen += RH_RF22_RXFFAFULL_THRESHOLD;
+}
+
+// Clear the FIFOs
+void RH_RF22::resetFifos()
+{
+    spiWrite(RH_RF22_REG_08_OPERATING_MODE2, RH_RF22_FFCLRRX | RH_RF22_FFCLRTX);
+    spiWrite(RH_RF22_REG_08_OPERATING_MODE2, 0);
+}
+
+// Clear the Rx FIFO
+void RH_RF22::resetRxFifo()
+{
+    spiWrite(RH_RF22_REG_08_OPERATING_MODE2, RH_RF22_FFCLRRX);
+    spiWrite(RH_RF22_REG_08_OPERATING_MODE2, 0);
+}
+
+// CLear the TX FIFO
+void RH_RF22::resetTxFifo()
+{
+    spiWrite(RH_RF22_REG_08_OPERATING_MODE2, RH_RF22_FFCLRTX);
+    spiWrite(RH_RF22_REG_08_OPERATING_MODE2, 0);
+}
+
+// Default implmentation does nothing. Override if you wish
+void RH_RF22::handleExternalInterrupt()
+{
+}
+
+// Default implmentation does nothing. Override if you wish
+void RH_RF22::handleWakeupTimerInterrupt()
+{
+}
+
+void RH_RF22::setPromiscuous(bool promiscuous)
+{
+    RHSPIDriver::setPromiscuous(promiscuous);
+    spiWrite(RH_RF22_REG_43_HEADER_ENABLE3, promiscuous ? 0x00 : 0xff);
+}
+
+bool RH_RF22::setCRCPolynomial(CRCPolynomial polynomial)
+{
+    if (polynomial >= CRC_CCITT &&
+	polynomial <= CRC_Biacheva)
+    {
+	_polynomial = polynomial;
+	return true;
+    }
+    else
+	return false;
+}
+
+uint8_t RH_RF22::maxMessageLength()
+{
+    return RH_RF22_MAX_MESSAGE_LEN;
+}
+
+void RH_RF22::setThisAddress(uint8_t thisAddress)
+{
+    RHSPIDriver::setThisAddress(thisAddress);
+    spiWrite(RH_RF22_REG_3F_CHECK_HEADER3, thisAddress);
+}
+
+uint32_t RH_RF22::getLastPreambleTime()
+{
+    return _lastPreambleTime;
+}
+
+void RH_RF22::setGpioReversed(bool gpioReversed)
+{
+    // Ensure the antenna can be switched automatically according to transmit and receive
+    // This assumes GPIO0(out) is connected to TX_ANT(in) to enable tx antenna during transmit
+    // This assumes GPIO1(out) is connected to RX_ANT(in) to enable rx antenna during receive
+    if (gpioReversed)
+    {
+	// Reversed for HAB-RFM22B-BOA HAB-RFM22B-BO, also Si4432 sold by Dorji.com via Tindie.com.
+	spiWrite(RH_RF22_REG_0B_GPIO_CONFIGURATION0, 0x15) ; // RX state
+	spiWrite(RH_RF22_REG_0C_GPIO_CONFIGURATION1, 0x12) ; // TX state
+    }
+    else
+    {
+	spiWrite(RH_RF22_REG_0B_GPIO_CONFIGURATION0, 0x12) ; // TX state
+	spiWrite(RH_RF22_REG_0C_GPIO_CONFIGURATION1, 0x15) ; // RX state
+    }
+}
+