RFM69.cpp

00001 //Port of RFM69 from lowpowerlab
00002 //Sync'd Feb. 6, 2015
00003 //spi register read/write routines from Karl Zweimuller's RF22
00004 //
00005 //
00006 //
00007 // **********************************************************************************
00008 // Driver definition for HopeRF RFM69W/RFM69HW/RFM69CW/RFM69HCW, Semtech SX1231/1231H
00009 // **********************************************************************************
00010 // Copyright Felix Rusu (2014), felix@lowpowerlab.com
00011 // http://lowpowerlab.com/
00012 // **********************************************************************************
00013 // License
00014 // **********************************************************************************
00015 // This program is free software; you can redistribute it 
00016 // and/or modify it under the terms of the GNU General    
00017 // Public License as published by the Free Software       
00018 // Foundation; either version 3 of the License, or        
00019 // (at your option) any later version.                    
00020 //                                                        
00021 // This program is distributed in the hope that it will   
00022 // be useful, but WITHOUT ANY WARRANTY; without even the  
00023 // implied warranty of MERCHANTABILITY or FITNESS FOR A   
00024 // PARTICULAR PURPOSE. See the GNU General Public        
00025 // License for more details.                              
00026 //                                                        
00027 // You should have received a copy of the GNU General    
00028 // Public License along with this program.
00029 // If not, see <http://www.gnu.org/licenses/>.
00030 //                                                        
00031 // Licence can be viewed at                               
00032 // http://www.gnu.org/licenses/gpl-3.0.txt
00033 //
00034 // Please maintain this license information along with authorship
00035 // and copyright notices in any redistribution of this code
00036 // **********************************************************************************// RF22.cpp
00037 //
00038 // Copyright (C) 2011 Mike McCauley
00039 // $Id: RF22.cpp,v 1.17 2013/02/06 21:33:56 mikem Exp mikem $
00040 // ported to mbed by Karl Zweimueller
00041 
00042 
00043 #include "mbed.h"
00044 #include "RFM69.h"
00045 #include <RFM69registers.h>
00046 #include <SPI.h>
00047 
00048 volatile uint8_t RFM69::DATA[RF69_MAX_DATA_LEN];
00049 volatile uint8_t RFM69::_mode;        // current transceiver state
00050 volatile uint8_t RFM69::DATALEN;
00051 volatile uint8_t RFM69::SENDERID;
00052 volatile uint8_t RFM69::TARGETID;     // should match _address
00053 volatile uint8_t RFM69::PAYLOADLEN;
00054 volatile uint8_t RFM69::ACK_REQUESTED;
00055 volatile uint8_t RFM69::ACK_RECEIVED; // should be polled immediately after sending a packet with ACK request
00056 volatile int16_t RFM69::RSSI;          // most accurate RSSI during reception (closest to the reception)
00057 
00058 RFM69::RFM69(PinName mosi, PinName miso, PinName sclk, PinName slaveSelectPin, PinName interrupt): 
00059       _slaveSelectPin(slaveSelectPin) ,  _spi(mosi, miso, sclk), _interrupt(interrupt) {
00060  
00061     // Setup the spi for 8 bit data, high steady state clock,
00062     // second edge capture, with a 1MHz clock rate
00063     _spi.format(8,0);
00064     _spi.frequency(1000000);
00065     _mode = RF69_MODE_STANDBY;
00066     _promiscuousMode = false;
00067     _powerLevel = 31;
00068 }
00069 
00070 bool RFM69::initialize(uint8_t freqBand, uint8_t nodeID, uint8_t networkID)
00071 {
00072   unsigned long start_to;
00073   const uint8_t CONFIG[][2] =
00074   {
00075     /* 0x01 */ { REG_OPMODE, RF_OPMODE_SEQUENCER_ON | RF_OPMODE_LISTEN_OFF | RF_OPMODE_STANDBY },
00076     /* 0x02 */ { REG_DATAMODUL, RF_DATAMODUL_DATAMODE_PACKET | RF_DATAMODUL_MODULATIONTYPE_FSK | RF_DATAMODUL_MODULATIONSHAPING_00 }, // no shaping
00077     /* 0x03 */ { REG_BITRATEMSB, RF_BITRATEMSB_55555}, // default: 4.8 KBPS
00078     /* 0x04 */ { REG_BITRATELSB, RF_BITRATELSB_55555},
00079     /* 0x05 */ { REG_FDEVMSB, RF_FDEVMSB_50000}, // default: 5KHz, (FDEV + BitRate / 2 <= 500KHz)
00080     /* 0x06 */ { REG_FDEVLSB, RF_FDEVLSB_50000},
00081 
00082     /* 0x07 */ { REG_FRFMSB, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFMSB_315 : (freqBand==RF69_433MHZ ? RF_FRFMSB_433 : (freqBand==RF69_868MHZ ? RF_FRFMSB_868 : RF_FRFMSB_915))) },
00083     /* 0x08 */ { REG_FRFMID, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFMID_315 : (freqBand==RF69_433MHZ ? RF_FRFMID_433 : (freqBand==RF69_868MHZ ? RF_FRFMID_868 : RF_FRFMID_915))) },
00084     /* 0x09 */ { REG_FRFLSB, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFLSB_315 : (freqBand==RF69_433MHZ ? RF_FRFLSB_433 : (freqBand==RF69_868MHZ ? RF_FRFLSB_868 : RF_FRFLSB_915))) },
00085 
00086     // looks like PA1 and PA2 are not implemented on RFM69W, hence the max output power is 13dBm
00087     // +17dBm and +20dBm are possible on RFM69HW
00088     // +13dBm formula: Pout = -18 + OutputPower (with PA0 or PA1**)
00089     // +17dBm formula: Pout = -14 + OutputPower (with PA1 and PA2)**
00090     // +20dBm formula: Pout = -11 + OutputPower (with PA1 and PA2)** and high power PA settings (section 3.3.7 in datasheet)
00091     ///* 0x11 */ { REG_PALEVEL, RF_PALEVEL_PA0_ON | RF_PALEVEL_PA1_OFF | RF_PALEVEL_PA2_OFF | RF_PALEVEL_OUTPUTPOWER_11111},
00092     ///* 0x13 */ { REG_OCP, RF_OCP_ON | RF_OCP_TRIM_95 }, // over current protection (default is 95mA)
00093     /* 0x11 */ { REG_PALEVEL, RF_PALEVEL_PA0_ON | RF_PALEVEL_PA1_ON | RF_PALEVEL_PA2_ON | RF_PALEVEL_OUTPUTPOWER_11111},
00094     /* 0x13 */ { REG_OCP, RF_OCP_ON | RF_OCP_TRIM_95 }, // over current protection (default is 95mA)
00095 
00096     // RXBW defaults are { REG_RXBW, RF_RXBW_DCCFREQ_010 | RF_RXBW_MANT_24 | RF_RXBW_EXP_5} (RxBw: 10.4KHz)
00097     /* 0x19 */ { REG_RXBW, RF_RXBW_DCCFREQ_010 | RF_RXBW_MANT_16 | RF_RXBW_EXP_2 }, // (BitRate < 2 * RxBw)
00098     //for BR-19200: /* 0x19 */ { REG_RXBW, RF_RXBW_DCCFREQ_010 | RF_RXBW_MANT_24 | RF_RXBW_EXP_3 },
00099     ///* 0x25 */ { REG_DIOMAPPING1, RF_DIOMAPPING1_DIO0_01 }, // DIO0 is the only IRQ we're using
00100     ///* 0x26 */ { REG_DIOMAPPING2, RF_DIOMAPPING2_CLKOUT_OFF }, // DIO5 ClkOut disable for power saving
00101     ///* 0x28 */ { REG_IRQFLAGS2, RF_IRQFLAGS2_FIFOOVERRUN }, // writing to this bit ensures that the FIFO & status flags are reset
00102     /* 0x29 */ { REG_RSSITHRESH, 220 }, // must be set to dBm = (-Sensitivity / 2), default is 0xE4 = 228 so -114dBm
00103     /* 0x2D */ { REG_PREAMBLELSB, RF_PREAMBLESIZE_LSB_VALUE }, // default 3 preamble bytes 0xAAAAAA
00104     /* 0x2E */ { REG_SYNCCONFIG, RF_SYNC_ON | RF_SYNC_FIFOFILL_AUTO | RF_SYNC_SIZE_2 | RF_SYNC_TOL_0 },
00105     /* 0x2F */ { REG_SYNCVALUE1, 0x2D },      // attempt to make this compatible with sync1 byte of RFM12B lib
00106     /* 0x30 */ { REG_SYNCVALUE2, networkID }, // NETWORK ID
00107     /* 0x37 */ { REG_PACKETCONFIG1, RF_PACKET1_FORMAT_VARIABLE | RF_PACKET1_DCFREE_WHITENING | RF_PACKET1_CRC_ON | RF_PACKET1_CRCAUTOCLEAR_ON | RF_PACKET1_ADRSFILTERING_OFF },
00108     /* 0x38 */ { REG_PAYLOADLENGTH, 66 }, // in variable length mode: the max frame size, not used in TX
00109     ///* 0x39 */ { REG_NODEADRS, nodeID }, // turned off because we're not using address filtering
00110     /* 0x3C */ { REG_FIFOTHRESH, RF_FIFOTHRESH_TXSTART_FIFONOTEMPTY | RF_FIFOTHRESH_VALUE }, // TX on FIFO not empty
00111     /* 0x3D */ { REG_PACKETCONFIG2, RF_PACKET2_RXRESTARTDELAY_2BITS | RF_PACKET2_AUTORXRESTART_ON | RF_PACKET2_AES_OFF }, // RXRESTARTDELAY must match transmitter PA ramp-down time (bitrate dependent)
00112     //for BR-19200: /* 0x3D */ { REG_PACKETCONFIG2, RF_PACKET2_RXRESTARTDELAY_NONE | RF_PACKET2_AUTORXRESTART_ON | RF_PACKET2_AES_OFF }, // RXRESTARTDELAY must match transmitter PA ramp-down time (bitrate dependent)
00113     /* 0x6F */ { REG_TESTDAGC, RF_DAGC_IMPROVED_LOWBETA0 }, // run DAGC continuously in RX mode for Fading Margin Improvement, recommended default for AfcLowBetaOn=0
00114     {255, 0}
00115   };
00116 // Timer for ms waits
00117     t.start();
00118      _slaveSelectPin = 1;
00119 
00120     // Setup the spi for 8 bit data : 1RW-bit 7 adressbit and  8 databit
00121     // second edge capture, with a 10MHz clock rate
00122     _spi.format(8,0);
00123     _spi.frequency(1000000);
00124 
00125 #define TIME_OUT 50
00126   
00127   start_to = t.read_ms() ;
00128 
00129   do writeReg(REG_SYNCVALUE1, 0xaa); while (readReg(REG_SYNCVALUE1) != 0xaa);// && t.read_ms()-start_to < TIME_OUT);
00130   if (t.read_ms()-start_to >= TIME_OUT) return (false);
00131     
00132   // Set time out 
00133   start_to = t.read_ms()  ;  
00134     do writeReg(REG_SYNCVALUE1, 0x55); while (readReg(REG_SYNCVALUE1) != 0x55);// && t.read_ms()-start_to < TIME_OUT);
00135   if (t.read_ms()-start_to >= TIME_OUT) return (false);
00136   for (uint8_t i = 0; CONFIG[i][0] != 255; i++)
00137     writeReg(CONFIG[i][0], CONFIG[i][1]);
00138 
00139   // Encryption is persistent between resets and can trip you up during debugging.
00140   // Disable it during initialization so we always start from a known state.
00141   encrypt(0);
00142 
00143   //setHighPower(_isRFM69HW); // called regardless if it's a RFM69W or RFM69HW
00144   setMode(RF69_MODE_STANDBY);
00145     // Set up interrupt handler
00146     start_to = t.read_ms() ;
00147     while (((readReg(REG_IRQFLAGS1) & RF_IRQFLAGS1_MODEREADY) == 0x00) && t.read_ms()-start_to < TIME_OUT); // Wait for ModeReady
00148   if (t.read_ms()-start_to >= TIME_OUT) return (false);
00149 
00150     _interrupt.rise(this, &RFM69::isr0);
00151  
00152   _address = nodeID;
00153    return true;
00154 }
00155 // return the frequency (in Hz)
00156 uint32_t RFM69::getFrequency()
00157 {
00158   return RF69_FSTEP * (((uint32_t) readReg(REG_FRFMSB) << 16) + ((uint16_t) readReg(REG_FRFMID) << 8) + readReg(REG_FRFLSB));
00159 }
00160 
00161 // set the frequency (in Hz)
00162 void RFM69::setFrequency(uint32_t freqHz)
00163 {
00164   uint8_t oldMode = _mode;
00165   if (oldMode == RF69_MODE_TX) {
00166     setMode(RF69_MODE_RX);
00167   }
00168   freqHz /= RF69_FSTEP; // divide down by FSTEP to get FRF
00169   writeReg(REG_FRFMSB, freqHz >> 16);
00170   writeReg(REG_FRFMID, freqHz >> 8);
00171   writeReg(REG_FRFLSB, freqHz);
00172   if (oldMode == RF69_MODE_RX) {
00173     setMode(RF69_MODE_SYNTH);
00174   }
00175   setMode(oldMode);
00176 }
00177 
00178 void RFM69::setMode(uint8_t newMode)
00179 {
00180   if (newMode == _mode)
00181     return;
00182 
00183   switch (newMode) {
00184     case RF69_MODE_TX:
00185       writeReg(REG_OPMODE, (readReg(REG_OPMODE) & 0xE3) | RF_OPMODE_TRANSMITTER);
00186       if (_isRFM69HW) setHighPowerRegs(true);
00187       break;
00188     case RF69_MODE_RX:
00189       writeReg(REG_OPMODE, (readReg(REG_OPMODE) & 0xE3) | RF_OPMODE_RECEIVER);
00190       if (_isRFM69HW) setHighPowerRegs(false);
00191       break;
00192     case RF69_MODE_SYNTH:
00193       writeReg(REG_OPMODE, (readReg(REG_OPMODE) & 0xE3) | RF_OPMODE_SYNTHESIZER);
00194       break;
00195     case RF69_MODE_STANDBY:
00196       writeReg(REG_OPMODE, (readReg(REG_OPMODE) & 0xE3) | RF_OPMODE_STANDBY);
00197       break;
00198     case RF69_MODE_SLEEP:
00199       writeReg(REG_OPMODE, (readReg(REG_OPMODE) & 0xE3) | RF_OPMODE_SLEEP);
00200       break;
00201     default:
00202       return;
00203   }
00204 
00205   // we are using packet mode, so this check is not really needed
00206   // but waiting for mode ready is necessary when going from sleep because the FIFO may not be immediately available from previous mode
00207   while (_mode == RF69_MODE_SLEEP && (readReg(REG_IRQFLAGS1) & RF_IRQFLAGS1_MODEREADY) == 0x00); // wait for ModeReady
00208   _mode = newMode;
00209 }
00210 
00211 void RFM69::sleep() {
00212   setMode(RF69_MODE_SLEEP);
00213 }
00214 
00215 void RFM69::setAddress(uint8_t addr)
00216 {
00217   _address = addr;
00218   writeReg(REG_NODEADRS, _address);
00219 }
00220 
00221 void RFM69::setNetwork(uint8_t networkID)
00222 {
00223   writeReg(REG_SYNCVALUE2, networkID);
00224 }
00225 
00226 // set output power: 0 = min, 31 = max
00227 // this results in a "weaker" transmitted signal, and directly results in a lower RSSI at the receiver
00228 void RFM69::setPowerLevel(uint8_t powerLevel)
00229 {
00230   _powerLevel = powerLevel;
00231   writeReg(REG_PALEVEL, (readReg(REG_PALEVEL) & 0xE0) | (_powerLevel > 31 ? 31 : _powerLevel));
00232 }
00233 
00234 bool RFM69::canSend()
00235 {
00236   if (_mode == RF69_MODE_RX && PAYLOADLEN == 0 && readRSSI() < CSMA_LIMIT) // if signal stronger than -100dBm is detected assume channel activity
00237   {
00238     setMode(RF69_MODE_STANDBY);
00239     return true;
00240   }
00241   return false;
00242 }
00243 
00244 void RFM69::send(uint8_t toAddress, const void* buffer, uint8_t bufferSize, bool requestACK)
00245 {
00246   writeReg(REG_PACKETCONFIG2, (readReg(REG_PACKETCONFIG2) & 0xFB) | RF_PACKET2_RXRESTART); // avoid RX deadlocks
00247   //uint32_t now = t.read_ms();
00248   //while (!canSend() && t.read_ms() - now < RF69_CSMA_LIMIT_MS) receiveDone();
00249   sendFrame(toAddress, buffer, bufferSize, requestACK, false);
00250 }
00251 
00252 // to increase the chance of getting a packet across, call this function instead of send
00253 // and it handles all the ACK requesting/retrying for you :)
00254 // The only twist is that you have to manually listen to ACK requests on the other side and send back the ACKs
00255 // The reason for the semi-automaton is that the lib is interrupt driven and
00256 // requires user action to read the received data and decide what to do with it
00257 // replies usually take only 5..8ms at 50kbps@915MHz
00258 bool RFM69::sendWithRetry(uint8_t toAddress, const void* buffer, uint8_t bufferSize, uint8_t retries, uint8_t retryWaitTime) {
00259   uint32_t sentTime;
00260   for (uint8_t i = 0; i <= retries; i++)
00261   {
00262     send(toAddress, buffer, bufferSize, true);
00263     sentTime = t.read_ms();
00264     while (t.read_ms() - sentTime < retryWaitTime)
00265     {
00266       if (ACKReceived(toAddress))
00267       {
00268         //Serial.print(" ~ms:"); Serial.print(t.read_ms() - sentTime);
00269         return true;
00270       }
00271     }
00272     //Serial.print(" RETRY#"); Serial.println(i + 1);
00273   }
00274   return false;
00275 }
00276 
00277 // should be polled immediately after sending a packet with ACK request
00278 bool RFM69::ACKReceived(uint8_t fromNodeID) {
00279   if (receiveDone())
00280     return (SENDERID == fromNodeID || fromNodeID == RF69_BROADCAST_ADDR) && ACK_RECEIVED;
00281   return false;
00282 }
00283 
00284 // check whether an ACK was requested in the last received packet (non-broadcasted packet)
00285 bool RFM69::ACKRequested() {
00286   return ACK_REQUESTED && (TARGETID != RF69_BROADCAST_ADDR);
00287 }
00288 
00289 // should be called immediately after reception in case sender wants ACK
00290 void RFM69::sendACK(const void* buffer, uint8_t bufferSize) {
00291   uint8_t sender = SENDERID;
00292   int16_t _RSSI = RSSI; // save payload received RSSI value
00293   writeReg(REG_PACKETCONFIG2, (readReg(REG_PACKETCONFIG2) & 0xFB) | RF_PACKET2_RXRESTART); // avoid RX deadlocks
00294   uint32_t now = t.read_ms();
00295   while (!canSend() && t.read_ms() - now < RF69_CSMA_LIMIT_MS) receiveDone();
00296   sendFrame(sender, buffer, bufferSize, false, true);
00297   RSSI = _RSSI; // restore payload RSSI
00298 }
00299 
00300 void RFM69::sendFrame(uint8_t toAddress, const void* buffer, uint8_t bufferSize, bool requestACK, bool sendACK)
00301 {
00302   setMode(RF69_MODE_STANDBY); // turn off receiver to prevent reception while filling fifo
00303   while ((readReg(REG_IRQFLAGS1) & RF_IRQFLAGS1_MODEREADY) == 0x00); // wait for ModeReady
00304   //writeReg(REG_DIOMAPPING1, RF_DIOMAPPING1_DIO0_00); // DIO0 is "Packet Sent"
00305   if (bufferSize > RF69_MAX_DATA_LEN) bufferSize = RF69_MAX_DATA_LEN;
00306 
00307  // control byte
00308   uint8_t CTLbyte = 0x00;
00309   if (sendACK)
00310     CTLbyte = 0x80;
00311   else if (requestACK)
00312     CTLbyte = 0x40;
00313 
00314    select();
00315    _spi.write(REG_FIFO | 0x80); 
00316     _spi.write(bufferSize + 3);
00317    _spi.write(toAddress);
00318    _spi.write(_address);
00319    _spi.write(CTLbyte);
00320  
00321   for (uint8_t i = 0; i < bufferSize; i++)
00322      _spi.write(((uint8_t*) buffer)[i]);
00323   unselect();
00324 
00325   // no need to wait for transmit mode to be ready since its handled by the radio
00326   setMode(RF69_MODE_TX);
00327   uint32_t txStart = t.read_ms();
00328   //while (_interrupt == 0 && t.read_ms() - txStart < RF69_TX_LIMIT_MS); // wait for DIO0 to turn HIGH signalling transmission finish
00329   while ((readReg(REG_IRQFLAGS2) & RF_IRQFLAGS2_PACKETSENT) == 0x00); // wait for ModeReady
00330   setMode(RF69_MODE_STANDBY);
00331 }
00332 // ON  = disable filtering to capture all frames on network
00333 // OFF = enable node/broadcast filtering to capture only frames sent to this/broadcast address
00334 void RFM69::promiscuous(bool onOff) {
00335   _promiscuousMode = onOff;
00336   //writeReg(REG_PACKETCONFIG1, (readReg(REG_PACKETCONFIG1) & 0xF9) | (onOff ? RF_PACKET1_ADRSFILTERING_OFF : RF_PACKET1_ADRSFILTERING_NODEBROADCAST));
00337 }
00338 
00339 void RFM69::setHighPower(bool onOff) {
00340   _isRFM69HW = onOff;
00341   writeReg(REG_OCP, _isRFM69HW ? RF_OCP_OFF : RF_OCP_ON);
00342   if (_isRFM69HW) // turning ON
00343     writeReg(REG_PALEVEL, (readReg(REG_PALEVEL) & 0x1F) | RF_PALEVEL_PA1_ON | RF_PALEVEL_PA2_ON); // enable P1 & P2 amplifier stages
00344   else
00345     writeReg(REG_PALEVEL, RF_PALEVEL_PA0_ON | RF_PALEVEL_PA1_OFF | RF_PALEVEL_PA2_OFF | _powerLevel); // enable P0 only
00346 }
00347 
00348 void RFM69::setHighPowerRegs(bool onOff) {
00349   writeReg(REG_TESTPA1, onOff ? 0x5D : 0x55);
00350   writeReg(REG_TESTPA2, onOff ? 0x7C : 0x70);
00351 }
00352 
00353 /*
00354 void RFM69::setCS(uint8_t newSPISlaveSelect) {
00355     DigitalOut _slaveSelectPin(newSPISlaveSelect);
00356     _slaveSelectPin = 1;
00357 }
00358 */
00359 // for debugging
00360 void RFM69::readAllRegs()
00361 {
00362   uint8_t regVal,regAddr;
00363 
00364   for (regAddr = 1; regAddr <= 0x4F; regAddr++)
00365   {
00366     select();
00367     _spi.write(regAddr & 0x7F); // send address + r/w bit
00368     regVal = _spi.write(0);
00369  
00370  /*   Serial.print(regAddr, HEX);
00371     Serial.print(" - ");
00372     Serial.print(regVal,HEX);
00373     Serial.print(" - ");
00374     Serial.println(regVal,BIN);*/
00375   }
00376   unselect();
00377 }
00378 
00379 uint8_t RFM69::readTemperature(int8_t calFactor) // returns centigrade
00380 {
00381    uint8_t oldMode = _mode;
00382  
00383   setMode(RF69_MODE_STANDBY);
00384   writeReg(REG_TEMP1, RF_TEMP1_MEAS_START);
00385   while ((readReg(REG_TEMP1) & RF_TEMP1_MEAS_RUNNING));
00386   setMode(oldMode);
00387 
00388   return ~readReg(REG_TEMP2) + COURSE_TEMP_COEF + calFactor; // 'complement' corrects the slope, rising temp = rising val
00389 } // COURSE_TEMP_COEF puts reading in the ballpark, user can add additional correction
00390 
00391 void RFM69::rcCalibration()
00392 {
00393   writeReg(REG_OSC1, RF_OSC1_RCCAL_START);
00394   while ((readReg(REG_OSC1) & RF_OSC1_RCCAL_DONE) == 0x00);
00395 }
00396 // C++ level interrupt handler for this instance
00397 void RFM69::interruptHandler() {
00398 
00399   if (_mode == RF69_MODE_RX && (readReg(REG_IRQFLAGS2) & RF_IRQFLAGS2_PAYLOADREADY))
00400   {
00401     setMode(RF69_MODE_STANDBY);
00402     select();
00403 
00404     _spi.write(REG_FIFO & 0x7F);
00405     PAYLOADLEN = _spi.write(0);
00406     PAYLOADLEN = PAYLOADLEN > 66 ? 66 : PAYLOADLEN; // precaution
00407     TARGETID = _spi.write(0);
00408     if(!(_promiscuousMode || TARGETID == _address || TARGETID == RF69_BROADCAST_ADDR) // match this node's address, or broadcast address or anything in promiscuous mode
00409        || PAYLOADLEN < 3) // address situation could receive packets that are malformed and don't fit this libraries extra fields
00410     {
00411       PAYLOADLEN = 0;
00412       unselect();
00413       receiveBegin();
00414       return;
00415     }
00416 
00417     DATALEN = PAYLOADLEN - 3;
00418     SENDERID = _spi.write(0);
00419     uint8_t CTLbyte = _spi.write(0);
00420 
00421     ACK_RECEIVED = CTLbyte & 0x80; // extract ACK-received flag
00422     ACK_REQUESTED = CTLbyte & 0x40; // extract ACK-requested flag
00423 
00424     for (uint8_t i = 0; i < DATALEN; i++)
00425     {
00426       DATA[i] = _spi.write(0);
00427     }
00428     if (DATALEN < RF69_MAX_DATA_LEN) DATA[DATALEN] = 0; // add null at end of string
00429     unselect();
00430     setMode(RF69_MODE_RX);
00431   }
00432   RSSI = readRSSI();
00433 }
00434 
00435 
00436 // These are low level functions that call the interrupt handler for the correct instance of RFM69.
00437 void RFM69::isr0()
00438 {
00439      interruptHandler();
00440 }
00441 void RFM69::receiveBegin() {
00442   DATALEN = 0;
00443   SENDERID = 0;
00444   TARGETID = 0;
00445   PAYLOADLEN = 0;
00446   ACK_REQUESTED = 0;
00447   ACK_RECEIVED = 0;
00448   RSSI = 0;
00449   if (readReg(REG_IRQFLAGS2) & RF_IRQFLAGS2_PAYLOADREADY)
00450     writeReg(REG_PACKETCONFIG2, (readReg(REG_PACKETCONFIG2) & 0xFB) | RF_PACKET2_RXRESTART); // avoid RX deadlocks
00451   writeReg(REG_DIOMAPPING1, RF_DIOMAPPING1_DIO0_01); // set DIO0 to "PAYLOADREADY" in receive mode
00452   setMode(RF69_MODE_RX);
00453   _interrupt.enable_irq();
00454 }
00455 
00456 bool RFM69::receiveDone() {
00457   _interrupt.disable_irq();  // re-enabled in unselect() via setMode() or via receiveBegin()
00458   if (_mode == RF69_MODE_RX && PAYLOADLEN > 0)
00459   {
00460     setMode(RF69_MODE_STANDBY); // enables interrupts
00461     return true;
00462   }
00463   else if (_mode == RF69_MODE_RX) // already in RX no payload yet
00464   {
00465    _interrupt.enable_irq(); // explicitly re-enable interrupts
00466     return false;
00467   }
00468   receiveBegin();
00469   return false;
00470 }
00471 
00472 // To enable encryption: radio.encrypt("ABCDEFGHIJKLMNOP");
00473 // To disable encryption: radio.encrypt(null) or radio.encrypt(0)
00474 // KEY HAS TO BE 16 bytes !!!
00475 void RFM69::encrypt(const char* key) {
00476   setMode(RF69_MODE_STANDBY);
00477   if (key != 0)
00478   {
00479     select();
00480     _spi.write(REG_AESKEY1 | 0x80);
00481     for (uint8_t i = 0; i < 16; i++)
00482       _spi.write(key[i]);
00483     unselect();
00484   }
00485   writeReg(REG_PACKETCONFIG2, (readReg(REG_PACKETCONFIG2) & 0xFE) | (key ? 1 : 0));
00486 }
00487 
00488 int16_t RFM69::readRSSI(bool forceTrigger) {
00489   int16_t rssi = 0;
00490   if (forceTrigger)
00491   {
00492     // RSSI trigger not needed if DAGC is in continuous mode
00493     writeReg(REG_RSSICONFIG, RF_RSSI_START);
00494     while ((readReg(REG_RSSICONFIG) & RF_RSSI_DONE) == 0x00); // wait for RSSI_Ready
00495   }
00496   rssi = -readReg(REG_RSSIVALUE);
00497   rssi >>= 1;
00498   return rssi;
00499 }
00500 
00501 uint8_t RFM69::readReg(uint8_t addr)
00502 {
00503     select();
00504     _spi.write(addr & 0x7F); // Send the address with the write mask off
00505     uint8_t val = _spi.write(0); // The written value is ignored, reg value is read
00506     unselect();
00507     return val;
00508 }
00509 
00510 void RFM69::writeReg(uint8_t addr, uint8_t value)
00511 {
00512     select();
00513     _spi.write(addr | 0x80); // Send the address with the write mask on
00514     _spi.write(value); // New value follows
00515     unselect();
00516  }
00517 
00518 // select the transceiver
00519 void RFM69::select() {
00520    _interrupt.disable_irq();    // Disable Interrupts
00521 /*  // set RFM69 SPI settings
00522   SPI.setDataMode(SPI_MODE0);
00523   SPI.setBitOrder(MSBFIRST);
00524   SPI.setClockDivider(SPI_CLOCK_DIV4); // decided to slow down from DIV2 after SPI stalling in some instances, especially visible on mega1284p when RFM69 and FLASH chip both present  */
00525    _slaveSelectPin = 0;
00526 }
00527 
00528 // UNselect the transceiver chip
00529 void RFM69::unselect() {
00530     _slaveSelectPin = 1;
00531     _interrupt.enable_irq();     // Enable Interrupts
00532 }