Diff: RH_RF95.cpp

Revision:

0:e69d086cb053

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/RH_RF95.cpp	Sun Jun 11 04:05:05 2017 +0000
@@ -0,0 +1,399 @@
+// RH_RF95.cpp
+//
+// Copyright (C) 2011 Mike McCauley
+// $Id: RH_RF95.cpp,v 1.14 2017/03/04 00:59:41 mikem Exp $
+//
+// Ported to mbed - support only a single radio - Dan Julio - 5/2017 
+//
+
+#include <RH_RF95.h>
+
+// These are indexed by the values of ModemConfigChoice
+// Stored in flash (program) memory to save SRAM
+static const RH_RF95::ModemConfig MODEM_CONFIG_TABLE[] =
+{
+    //  1d,     1e,      26
+    { 0x72,   0x74,    0x00}, // Bw125Cr45Sf128 (the chip default)
+    { 0x92,   0x74,    0x00}, // Bw500Cr45Sf128
+    { 0x48,   0x94,    0x00}, // Bw31_25Cr48Sf512
+    { 0x78,   0xc4,    0x00}, // Bw125Cr48Sf4096
+    
+};
+
+RH_RF95::RH_RF95(swspi& spi, int ssNum)
+    :
+    _spi(spi),
+    _ssn(ssNum),
+    _rxBufValid(0)
+{
+}
+
+bool RH_RF95::init()
+{
+    // Set sleep mode, so we can also set LORA mode:
+    _spi.spiWrite(RH_RF95_REG_01_OP_MODE, RH_RF95_MODE_SLEEP | RH_RF95_LONG_RANGE_MODE, 0, _ssn);
+    wait_ms(10); // Wait for sleep mode to take over from say, CAD
+    // Check we are in sleep mode, with LORA set
+    if (_spi.spiRead(RH_RF95_REG_01_OP_MODE, 0, _ssn) != (RH_RF95_MODE_SLEEP | RH_RF95_LONG_RANGE_MODE))
+    {
+//        printf("REG_01_OP_MODE: 0x%2x\n", _spi.spiRead(RH_RF95_REG_01_OP_MODE, 0, _ssn));
+        return false; // No device present?
+    }
+
+    // Set up FIFO
+    // We configure so that we can use the entire 256 byte FIFO for either receive
+    // or transmit, but not both at the same time
+    _spi.spiWrite(RH_RF95_REG_0E_FIFO_TX_BASE_ADDR, 0, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_0F_FIFO_RX_BASE_ADDR, 0, 0, _ssn);
+
+    // Packet format is preamble + explicit-header + payload + crc
+    // Explicit Header Mode
+    // payload is TO + FROM + ID + FLAGS + message data
+    // RX mode is implmented with RXCONTINUOUS
+    // max message data length is 255 - 4 = 251 octets
+
+    setModeIdle();
+
+    // Set up default configuration
+    // No Sync Words in LORA mode.
+    setModemConfig(Bw125Cr45Sf128); // Radio default
+//    setModemConfig(Bw125Cr48Sf4096); // slow and reliable?
+    setPreambleLength(8); // Default is 8
+    // An innocuous ISM frequency, same as RF22's
+    setFrequency(434.0);
+    // Lowish power
+    setTxPower(13);
+
+    return true;
+}
+
+// C++ level interrupt handler for this instance
+// LORA is unusual in that it has several interrupt lines, and not a single, combined one.
+// On MiniWirelessLoRa, only one of the several interrupt lines (DI0) from the RFM95 is usefuly 
+// connnected to the processor.
+// We use this to get RxDone and TxDone interrupts
+void RH_RF95::handleInterrupt()
+{
+    // Read the interrupt register
+    uint8_t irq_flags = _spi.spiRead(RH_RF95_REG_12_IRQ_FLAGS, 0, _ssn);
+    if (_mode == RHModeRx && irq_flags & (RH_RF95_RX_TIMEOUT | RH_RF95_PAYLOAD_CRC_ERROR))
+    {
+        _rxBad++;
+    }
+    else if (_mode == RHModeRx && irq_flags & RH_RF95_RX_DONE)
+    {
+    // Have received a packet
+    uint8_t len = _spi.spiRead(RH_RF95_REG_13_RX_NB_BYTES, 0, _ssn);
+
+    // Reset the fifo read ptr to the beginning of the packet
+    _spi.spiWrite(RH_RF95_REG_0D_FIFO_ADDR_PTR, _spi.spiRead(RH_RF95_REG_10_FIFO_RX_CURRENT_ADDR, 0, _ssn), 0, _ssn);
+    _spi.spiBurstRead(RH_RF95_REG_00_FIFO, _buf, len, 0, _ssn);
+    _bufLen = len;
+    _spi.spiWrite(RH_RF95_REG_12_IRQ_FLAGS, 0xff, 0, _ssn); // Clear all IRQ flags
+
+    // Remember the last signal to noise ratio, LORA mode
+    // Per page 111, SX1276/77/78/79 datasheet
+    _lastSNR = (int8_t)_spi.spiRead(RH_RF95_REG_19_PKT_SNR_VALUE, 0, _ssn) / 4;
+
+    // Remember the RSSI of this packet, LORA mode
+    // this is according to the doc, but is it really correct?
+    // weakest receiveable signals are reported RSSI at about -66
+    _lastRssi = _spi.spiRead(RH_RF95_REG_1A_PKT_RSSI_VALUE, 0, _ssn);
+    // Adjust the RSSI, datasheet page 87
+    if (_lastSNR < 0)
+        _lastRssi = _lastRssi + _lastSNR;
+    else
+        _lastRssi = (int)_lastRssi * 16 / 15;
+    if (_usingHFport)
+        _lastRssi -= 157;
+    else
+        _lastRssi -= 164;
+        
+    // We have received a message.
+    validateRxBuf(); 
+    if (_rxBufValid)
+        setModeIdle(); // Got one 
+    }
+    else if (_mode == RHModeTx && irq_flags & RH_RF95_TX_DONE)
+    {
+        _txGood++;
+        setModeIdle();
+    }
+    else if (_mode == RHModeCad && irq_flags & RH_RF95_CAD_DONE)
+    {
+        _cad = irq_flags & RH_RF95_CAD_DETECTED;
+        setModeIdle();
+    }
+    
+    _spi.spiWrite(RH_RF95_REG_12_IRQ_FLAGS, 0xff, 0, _ssn); // Clear all IRQ flags
+}
+
+// Check whether the latest received message is complete and uncorrupted
+void RH_RF95::validateRxBuf()
+{
+    if (_bufLen < 4)
+        return; // Too short to be a real message
+    
+    // Extract the 4 headers
+    _rxHeaderTo    = _buf[0];
+    _rxHeaderFrom  = _buf[1];
+    _rxHeaderId    = _buf[2];
+    _rxHeaderFlags = _buf[3];
+    if (_promiscuous ||
+      _rxHeaderTo == _thisAddress ||
+      _rxHeaderTo == RH_BROADCAST_ADDRESS)
+    {
+        _rxGood++;
+        _rxBufValid = true;
+    }
+}
+
+bool RH_RF95::available()
+{
+    if (_mode == RHModeTx)
+        return false;
+    
+    setModeRx();
+    return _rxBufValid; // Will be set by the interrupt handler when a good message is received
+}
+
+void RH_RF95::clearRxBuf()
+{
+    _rxBufValid = false;
+    _bufLen = 0;
+}
+
+bool RH_RF95::recv(uint8_t* buf, uint8_t* len)
+{
+    if (!available())
+        return false;
+    
+    if (buf && len)
+    {
+        // Skip the 4 headers that are at the beginning of the rxBuf
+        if (*len > _bufLen-RH_RF95_HEADER_LEN)
+            *len = _bufLen-RH_RF95_HEADER_LEN;
+        memcpy(buf, _buf+RH_RF95_HEADER_LEN, *len);
+    }
+    clearRxBuf(); // This message accepted and cleared
+    return true;
+}
+
+bool RH_RF95::send(const uint8_t* data, uint8_t len)
+{
+    if (len > RH_RF95_MAX_MESSAGE_LEN)
+        return false;
+
+    waitPacketSent(); // Make sure we dont interrupt an outgoing message
+    setModeIdle();
+
+    if (!waitCAD()) 
+        return false;  // Check channel activity
+
+    // Position at the beginning of the FIFO
+    _spi.spiWrite(RH_RF95_REG_0D_FIFO_ADDR_PTR, 0, 0, _ssn);
+    // The headers
+    _spi.spiWrite(RH_RF95_REG_00_FIFO, _txHeaderTo, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_00_FIFO, _txHeaderFrom, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_00_FIFO, _txHeaderId, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_00_FIFO, _txHeaderFlags, 0, _ssn);
+    // The message data
+    _spi.spiBurstWrite(RH_RF95_REG_00_FIFO, data, len, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_22_PAYLOAD_LENGTH, len + RH_RF95_HEADER_LEN, 0, _ssn);
+
+    setModeTx(); // Start the transmitter
+    // when Tx is done, interruptHandler will fire and radio mode will return to STANDBY
+    return true;
+}
+
+bool RH_RF95::printRegisters()
+{
+    uint8_t registers[] = { 0x01, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x014, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27};
+
+    uint8_t i;
+    for (i = 0; i < sizeof(registers); i++)
+    {
+        printf("0x%x: 0x%x\n\r", registers[i], _spi.spiRead(registers[i], 0, _ssn));
+    }
+    return true;
+}
+
+uint8_t RH_RF95::maxMessageLength()
+{
+    return RH_RF95_MAX_MESSAGE_LEN;
+}
+
+bool RH_RF95::setFrequency(float centre)
+{
+    // Frf = FRF / FSTEP
+    uint32_t frf = (centre * 1000000.0f) / RH_RF95_FSTEP;
+    _spi.spiWrite(RH_RF95_REG_06_FRF_MSB, (frf >> 16) & 0xff, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_07_FRF_MID, (frf >> 8) & 0xff, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_08_FRF_LSB, frf & 0xff, 0, _ssn);
+    _usingHFport = (centre >= 779.0f);
+
+    return true;
+}
+
+void RH_RF95::setModeIdle()
+{
+    if (_mode != RHModeIdle)
+    {
+        _spi.spiWrite(RH_RF95_REG_01_OP_MODE, RH_RF95_MODE_STDBY, 0, _ssn);
+        _mode = RHModeIdle;
+    }
+}
+
+bool RH_RF95::sleep()
+{
+    if (_mode != RHModeSleep)
+    {
+        _spi.spiWrite(RH_RF95_REG_01_OP_MODE, RH_RF95_MODE_SLEEP, 0, _ssn);
+        _mode = RHModeSleep;
+    }
+    return true;
+}
+
+void RH_RF95::setModeRx()
+{
+    if (_mode != RHModeRx)
+    {
+        _spi.spiWrite(RH_RF95_REG_01_OP_MODE, RH_RF95_MODE_RXCONTINUOUS, 0, _ssn);
+        _spi.spiWrite(RH_RF95_REG_40_DIO_MAPPING1, 0x00, 0, _ssn); // Interrupt on RxDone
+        _mode = RHModeRx;
+    }
+}
+
+void RH_RF95::setModeTx()
+{
+    if (_mode != RHModeTx)
+    {
+        _spi.spiWrite(RH_RF95_REG_01_OP_MODE, RH_RF95_MODE_TX, 0, _ssn);
+        _spi.spiWrite(RH_RF95_REG_40_DIO_MAPPING1, 0x40, 0, _ssn); // Interrupt on TxDone
+        _mode = RHModeTx;
+    }
+}
+
+void RH_RF95::setTxPower(int8_t power, bool useRFO)
+{
+    // Sigh, different behaviours depending on whther the module use PA_BOOST or the RFO pin
+    // for the transmitter output
+    if (useRFO)
+    {
+        if (power > 14)
+            power = 14;
+        if (power < -1)
+            power = -1;
+        _spi.spiWrite(RH_RF95_REG_09_PA_CONFIG, RH_RF95_MAX_POWER | (power + 1), 0, _ssn);
+    }
+    else
+    {
+        if (power > 23)
+            power = 23;
+        if (power < 5)
+            power = 5;
+
+        // For RH_RF95_PA_DAC_ENABLE, manual says '+20dBm on PA_BOOST when OutputPower=0xf'
+        // RH_RF95_PA_DAC_ENABLE actually adds about 3dBm to all power levels. We will us it
+        // for 21, 22 and 23dBm
+        if (power > 20)
+        {
+            _spi.spiWrite(RH_RF95_REG_4D_PA_DAC, RH_RF95_PA_DAC_ENABLE, 0, _ssn);
+            power -= 3;
+        }
+        else
+        {
+            _spi.spiWrite(RH_RF95_REG_4D_PA_DAC, RH_RF95_PA_DAC_DISABLE, 0, _ssn);
+        }
+
+        // RFM95/96/97/98 does not have RFO pins connected to anything. Only PA_BOOST
+        // pin is connected, so must use PA_BOOST
+        // Pout = 2 + OutputPower.
+        // The documentation is pretty confusing on this topic: PaSelect says the max power is 20dBm,
+        // but OutputPower claims it would be 17dBm.
+        // My measurements show 20dBm is correct
+        _spi.spiWrite(RH_RF95_REG_09_PA_CONFIG, RH_RF95_PA_SELECT | (power-5), 0, _ssn);
+    }
+}
+
+// Sets registers from a canned modem configuration structure
+void RH_RF95::setModemRegisters(const ModemConfig* config)
+{
+    _spi.spiWrite(RH_RF95_REG_1D_MODEM_CONFIG1,       config->reg_1d, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_1E_MODEM_CONFIG2,       config->reg_1e, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_26_MODEM_CONFIG3,       config->reg_26, 0, _ssn);
+}
+
+// Set one of the canned FSK Modem configs
+// Returns true if its a valid choice
+bool RH_RF95::setModemConfig(ModemConfigChoice index)
+{
+    if (index > (signed int)(sizeof(MODEM_CONFIG_TABLE) / sizeof(ModemConfig)))
+        return false;
+
+    ModemConfig cfg;
+    memcpy(&cfg, &MODEM_CONFIG_TABLE[index], sizeof(RH_RF95::ModemConfig));
+    setModemRegisters(&cfg);
+
+    return true;
+}
+
+void RH_RF95::setPreambleLength(uint16_t bytes)
+{
+    _spi.spiWrite(RH_RF95_REG_20_PREAMBLE_MSB, bytes >> 8, 0, _ssn);
+    _spi.spiWrite(RH_RF95_REG_21_PREAMBLE_LSB, bytes & 0xff, 0, _ssn);
+}
+
+bool RH_RF95::isChannelActive()
+{
+    // Set mode RHModeCad
+    if (_mode != RHModeCad)
+    {
+        _spi.spiWrite(RH_RF95_REG_01_OP_MODE, RH_RF95_MODE_CAD, 0, _ssn);
+        _spi.spiWrite(RH_RF95_REG_40_DIO_MAPPING1, 0x80, 0, _ssn); // Interrupt on CadDone
+        _mode = RHModeCad;
+    }
+
+    while (_mode == RHModeCad)
+        Thread::yield();
+
+    return _cad;
+}
+
+void RH_RF95::enableTCXO()
+{
+    while ((_spi.spiRead(RH_RF95_REG_4B_TCXO, 0, _ssn) & RH_RF95_TCXO_TCXO_INPUT_ON) != RH_RF95_TCXO_TCXO_INPUT_ON)
+    {
+        sleep();
+        _spi.spiWrite(RH_RF95_REG_4B_TCXO, (_spi.spiRead(RH_RF95_REG_4B_TCXO, 0, _ssn) | RH_RF95_TCXO_TCXO_INPUT_ON), 0, _ssn);
+    } 
+}
+
+// From section 4.1.5 of SX1276/77/78/79
+// Ferror = FreqError * 2**24 * BW / Fxtal / 500
+int RH_RF95::frequencyError()
+{
+    int32_t freqerror = 0;
+
+    // Convert 2.5 bytes (5 nibbles, 20 bits) to 32 bit signed int
+    freqerror = _spi.spiRead(RH_RF95_REG_28_FEI_MSB, 0, _ssn) << 16;
+    freqerror |= _spi.spiRead(RH_RF95_REG_29_FEI_MID, 0, _ssn) << 8;
+    freqerror |= _spi.spiRead(RH_RF95_REG_2A_FEI_LSB, 0, _ssn);
+    // Sign extension into top 3 nibbles
+    if (freqerror & 0x80000)
+        freqerror |= 0xfff00000;
+
+    int error = 0; // In hertz
+    float bw_tab[] = {7.8, 10.4, 15.6, 20.8, 31.25, 41.7, 62.5, 125, 250, 500};
+    uint8_t bwindex = _spi.spiRead(RH_RF95_REG_1D_MODEM_CONFIG1, 0, _ssn) >> 4;
+    if (bwindex < (sizeof(bw_tab) / sizeof(float)))
+        error = (float)freqerror * bw_tab[bwindex] * ((float)(1L << 24) / (float)RH_RF95_FXOSC / 500.0f);
+    // else not defined
+
+    return error;
+}
+
+int RH_RF95::lastSNR()
+{
+    return _lastSNR;
+}