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395 lines
10 KiB
Go
395 lines
10 KiB
Go
// Package rfm69 RFM69 Implementation in Go
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package rfm69
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import (
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"log"
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"github.com/davecheney/gpio"
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"github.com/fulr/spidev"
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)
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const (
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spiPath = "/dev/spidev0.0"
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irqPin = gpio.GPIO25
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)
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// Device RFM69 Device
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type Device struct {
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SpiDevice *spidev.SPIDevice
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gpio gpio.Pin
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mode byte
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address byte
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network byte
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isRFM69HW bool
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powerLevel byte
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}
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// Global settings
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const (
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CsmaLimit = -80
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MaxDataLen = 66
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)
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// Data is the data structure for the protocol
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type Data struct {
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ToAddress byte
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FromAddress byte
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Data []byte
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RequestAck bool
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SendAck bool
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Rssi int
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}
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// NewDevice creates a new device
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func NewDevice(nodeID, networkID byte, isRfm69HW bool) (*Device, error) {
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pin, err := gpio.OpenPin(irqPin, gpio.ModeInput)
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if err != nil {
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return nil, err
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}
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spi, err := spidev.NewSPIDevice(spiPath)
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if err != nil {
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return nil, err
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}
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ret := &Device{
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SpiDevice: spi,
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gpio: pin,
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network: networkID,
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address: nodeID,
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isRFM69HW: isRfm69HW,
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powerLevel: 31,
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}
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err = ret.setup()
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return ret, err
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}
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// Close cleans up
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func (r *Device) Close() error {
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err := r.gpio.Close()
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if err != nil {
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return err
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}
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r.SpiDevice.Close()
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return err
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}
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func (r *Device) writeReg(addr, data byte) error {
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tx := make([]byte, 2)
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tx[0] = addr | 0x80
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tx[1] = data
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//log.Printf("write %x: %x", addr, data)
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_, err := r.SpiDevice.Xfer(tx)
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if err != nil {
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log.Println(err)
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}
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return err
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}
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func (r *Device) readReg(addr byte) (byte, error) {
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tx := make([]uint8, 2)
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tx[0] = addr & 0x7f
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tx[1] = 0
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rx, err := r.SpiDevice.Xfer(tx)
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if err != nil {
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log.Println(err)
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}
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return rx[1], err
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}
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func (r *Device) setup() error {
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config := [][]byte{
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/* 0x01 */ {REG_OPMODE, RF_OPMODE_SEQUENCER_ON | RF_OPMODE_LISTEN_OFF | RF_OPMODE_STANDBY},
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/* 0x02 */ {REG_DATAMODUL, RF_DATAMODUL_DATAMODE_PACKET | RF_DATAMODUL_MODULATIONTYPE_FSK | RF_DATAMODUL_MODULATIONSHAPING_00}, // no shaping
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/* 0x03 */ {REG_BITRATEMSB, RF_BITRATEMSB_55555}, // default: 4.8 KBPS
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/* 0x04 */ {REG_BITRATELSB, RF_BITRATELSB_55555},
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/* 0x05 */ {REG_FDEVMSB, RF_FDEVMSB_50000}, // default: 5KHz, (FDEV + BitRate / 2 <= 500KHz)
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/* 0x06 */ {REG_FDEVLSB, RF_FDEVLSB_50000},
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/* 0x07 */ {REG_FRFMSB, RF_FRFMSB_868},
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/* 0x08 */ {REG_FRFMID, RF_FRFMID_868},
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/* 0x09 */ {REG_FRFLSB, RF_FRFLSB_868},
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// looks like PA1 and PA2 are not implemented on RFM69W, hence the max output power is 13dBm
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// +17dBm and +20dBm are possible on RFM69HW
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// +13dBm formula: Pout = -18 + OutputPower (with PA0 or PA1**)
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// +17dBm formula: Pout = -14 + OutputPower (with PA1 and PA2)**
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// +20dBm formula: Pout = -11 + OutputPower (with PA1 and PA2)** and high power PA settings (section 3.3.7 in datasheet)
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///* 0x11 */ { REG_PALEVEL, RF_PALEVEL_PA0_ON | RF_PALEVEL_PA1_OFF | RF_PALEVEL_PA2_OFF | RF_PALEVEL_OUTPUTPOWER_11111},
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///* 0x13 */ { REG_OCP, RF_OCP_ON | RF_OCP_TRIM_95 }, // over current protection (default is 95mA)
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// RXBW defaults are { REG_RXBW, RF_RXBW_DCCFREQ_010 | RF_RXBW_MANT_24 | RF_RXBW_EXP_5} (RxBw: 10.4KHz)
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/* 0x19 */ {REG_RXBW, RF_RXBW_DCCFREQ_010 | RF_RXBW_MANT_16 | RF_RXBW_EXP_2}, // (BitRate < 2 * RxBw)
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//for BR-19200: /* 0x19 */ { REG_RXBW, RF_RXBW_DCCFREQ_010 | RF_RXBW_MANT_24 | RF_RXBW_EXP_3 },
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/* 0x25 */ {REG_DIOMAPPING1, RF_DIOMAPPING1_DIO0_01}, // DIO0 is the only IRQ we're using
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/* 0x26 */ {REG_DIOMAPPING2, RF_DIOMAPPING2_CLKOUT_OFF}, // DIO5 ClkOut disable for power saving
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/* 0x28 */ {REG_IRQFLAGS2, RF_IRQFLAGS2_FIFOOVERRUN}, // writing to this bit ensures that the FIFO & status flags are reset
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/* 0x29 */ //{REG_RSSITHRESH, 220}, // must be set to dBm = (-Sensitivity / 2), default is 0xE4 = 228 so -114dBm
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///* 0x2D */ { REG_PREAMBLELSB, RF_PREAMBLESIZE_LSB_VALUE } // default 3 preamble bytes 0xAAAAAA
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/* 0x2E */ {REG_SYNCCONFIG, RF_SYNC_ON | RF_SYNC_FIFOFILL_AUTO | RF_SYNC_SIZE_2 | RF_SYNC_TOL_0},
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/* 0x2F */ {REG_SYNCVALUE1, 0x2D}, // attempt to make this compatible with sync1 byte of RFM12B lib
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/* 0x30 */ {REG_SYNCVALUE2, r.network}, // NETWORK ID
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/* 0x37 */ {REG_PACKETCONFIG1, RF_PACKET1_FORMAT_VARIABLE | RF_PACKET1_DCFREE_OFF | RF_PACKET1_CRC_ON | RF_PACKET1_CRCAUTOCLEAR_ON | RF_PACKET1_ADRSFILTERING_OFF},
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/* 0x38 */ {REG_PAYLOADLENGTH, 66}, // in variable length mode: the max frame size, not used in TX
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///* 0x39 */ { REG_NODEADRS, nodeID }, // turned off because we're not using address filtering
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/* 0x3C */ {REG_FIFOTHRESH, RF_FIFOTHRESH_TXSTART_FIFONOTEMPTY | RF_FIFOTHRESH_VALUE}, // TX on FIFO not empty
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/* 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)
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//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)
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/* 0x6F */ {REG_TESTDAGC, RF_DAGC_IMPROVED_LOWBETA0}, // run DAGC continuously in RX mode for Fading Margin Improvement, recommended default for AfcLowBetaOn=0
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}
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for data, err := r.readReg(REG_SYNCVALUE1); err == nil && data != 0xAA; data, err = r.readReg(REG_SYNCVALUE1) {
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err := r.writeReg(REG_SYNCVALUE1, 0xAA)
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if err != nil {
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return err
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}
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}
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for data, err := r.readReg(REG_SYNCVALUE1); err == nil && data != 0x55; data, err = r.readReg(REG_SYNCVALUE1) {
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r.writeReg(REG_SYNCVALUE1, 0x55)
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if err != nil {
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return err
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}
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}
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for _, c := range config {
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err := r.writeReg(c[0], c[1])
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if err != nil {
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return err
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}
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}
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err := r.Encrypt([]byte{})
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if err != nil {
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return err
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}
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err = r.setHighPower(r.isRFM69HW)
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if err != nil {
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return err
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}
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err = r.SetMode(RF_OPMODE_STANDBY)
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if err != nil {
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return err
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}
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err = r.waitForMode()
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return err
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}
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func (r *Device) waitForMode() error {
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for {
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reg, err := r.readReg(REG_IRQFLAGS1)
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if err != nil {
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return err
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}
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if reg&RF_IRQFLAGS1_MODEREADY != 0 {
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break
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}
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}
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return nil
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}
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// Encrypt sets the encryption key and enables AES encryption
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func (r *Device) Encrypt(key []byte) error {
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var turnOn byte
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if len(key) == 16 {
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turnOn = 1
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tx := make([]byte, 17)
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tx[0] = REG_AESKEY1 | 0x80
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copy(tx[1:], key)
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if _, err := r.SpiDevice.Xfer(tx); err != nil {
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return err
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}
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}
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return r.readWriteReg(REG_PACKETCONFIG2, 0xFE, turnOn)
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}
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// SetMode sets operation mode
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func (r *Device) SetMode(newMode byte) error {
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if newMode == r.mode {
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return nil
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}
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err := r.readWriteReg(REG_OPMODE, 0xE3, newMode)
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if err != nil {
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return err
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}
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if r.isRFM69HW && (newMode == RF_OPMODE_RECEIVER || newMode == RF_OPMODE_TRANSMITTER) {
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err := r.setHighPowerRegs(newMode == RF_OPMODE_TRANSMITTER)
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if err != nil {
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return err
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}
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}
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if r.mode == RF_OPMODE_SLEEP {
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err = r.waitForMode()
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if err != nil {
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return err
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}
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}
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r.mode = newMode
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return nil
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}
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// SetModeAndWait sets the mode and waits for it
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func (r *Device) SetModeAndWait(newMode byte) error {
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err := r.SetMode(RF_OPMODE_STANDBY)
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if err != nil {
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return err
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}
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err = r.waitForMode()
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if err != nil {
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return err
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}
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return nil
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}
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func (r *Device) setHighPower(turnOn bool) error {
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r.isRFM69HW = turnOn
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ocp := byte(RF_OCP_ON)
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if r.isRFM69HW {
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ocp = RF_OCP_OFF
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}
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err := r.writeReg(REG_OCP, ocp)
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if err != nil {
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return err
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}
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if r.isRFM69HW {
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err = r.readWriteReg(REG_PALEVEL, 0x1F, RF_PALEVEL_PA1_ON|RF_PALEVEL_PA2_ON)
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} else {
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err = r.readWriteReg(REG_PALEVEL, 0, RF_PALEVEL_PA0_ON|RF_PALEVEL_PA1_OFF|RF_PALEVEL_PA2_OFF|r.powerLevel)
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}
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return err
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}
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func (r *Device) setHighPowerRegs(turnOn bool) (err error) {
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var (
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testPa1 byte = 0x55
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testPa2 byte = 0x70
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)
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if turnOn {
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testPa1 = 0x5D
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testPa2 = 0x7C
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}
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err = r.writeReg(REG_TESTPA1, testPa1)
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if err != nil {
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return
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}
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err = r.writeReg(REG_TESTPA2, testPa2)
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return
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}
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// SetNetwork sets the network ID
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func (r *Device) SetNetwork(networkID byte) error {
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r.network = networkID
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return r.writeReg(REG_SYNCVALUE2, networkID)
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}
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// SetAddress sets the node address
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func (r *Device) SetAddress(address byte) error {
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r.address = address
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return r.writeReg(REG_NODEADRS, address)
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}
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// SetPowerLevel sets the TX power
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func (r *Device) SetPowerLevel(powerLevel byte) error {
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r.powerLevel = powerLevel
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if r.powerLevel > 31 {
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r.powerLevel = 31
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}
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return r.readWriteReg(REG_PALEVEL, 0xE0, r.powerLevel)
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}
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func (r *Device) canSend() (bool, error) {
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// if signal stronger than -100dBm is detected assume channel activity
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if r.mode == RF_OPMODE_RECEIVER {
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rssi, err := r.readRSSI(false)
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if err != nil {
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return false, err
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}
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if rssi < CsmaLimit {
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err = r.SetMode(RF_OPMODE_STANDBY)
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return true, err
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}
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}
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return false, nil
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}
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func (r *Device) readRSSI(forceTrigger bool) (rssi int, err error) {
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if forceTrigger {
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// RSSI trigger not needed if DAGC is in continuous mode
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err = r.writeReg(REG_RSSICONFIG, RF_RSSI_START)
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if err != nil {
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return
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}
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for {
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data, err := r.readReg(REG_RSSICONFIG)
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if err != nil {
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return 0, err
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}
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if data&RF_RSSI_DONE != 0 {
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break
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}
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}
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}
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data, err := r.readReg(REG_RSSIVALUE)
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if err != nil {
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return
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}
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rssi = -int(data) / 2
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return
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}
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func (r *Device) readWriteReg(reg, andMask, orMask byte) error {
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regValue, err := r.readReg(reg)
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if err != nil {
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return err
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}
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regValue = (regValue & andMask) | orMask
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return r.writeReg(reg, regValue)
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}
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func (r *Device) writeFifo(data *Data) error {
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buffersize := len(data.Data)
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if buffersize > MaxDataLen {
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buffersize = MaxDataLen
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}
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tx := make([]byte, buffersize+5)
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// write to FIFO
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tx[0] = REG_FIFO | 0x80
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tx[1] = byte(buffersize + 3)
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tx[2] = data.ToAddress
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tx[3] = r.address
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if data.RequestAck {
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tx[4] = 0x40
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}
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if data.SendAck {
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tx[4] = 0x80
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}
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copy(tx[5:], data.Data[:buffersize])
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_, err := r.SpiDevice.Xfer(tx)
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return err
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}
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func (r *Device) readFifo() (Data, error) {
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var err error
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data := Data{}
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data.Rssi, err = r.readRSSI(false)
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if err != nil {
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return data, err
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}
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tx := new([67]byte)
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tx[0] = REG_FIFO & 0x7f
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rx, err := r.SpiDevice.Xfer(tx[:3])
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if err != nil {
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return data, err
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}
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data.ToAddress = rx[2]
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length := rx[1] - 3
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if length > 66 {
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length = 66
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}
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rx, err = r.SpiDevice.Xfer(tx[:length+3])
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if err != nil {
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return data, err
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}
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data.FromAddress = rx[1]
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data.SendAck = bool(rx[2]&0x80 > 0)
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data.RequestAck = bool(rx[2]&0x40 > 0)
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data.Data = rx[3:]
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return data, nil
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}
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