Merge pull request #1 from soypat/sx128x

bare minimum sx128x setup

lora.go

@@ -22,8 +22,8 @@ type Config struct {
 	// Must be set when working with implicit headers.
 	MaxImplicitPayloadLength uint8
 	CodingRate               CodingRate
-	SpreadFactor             SpreadFactor
-	SyncWord                 uint8
+	SpreadingFactor          SpreadingFactor
+	SyncWord                 uint16 // for new chips sync word is full 16 bits
 	TxPower                  int8   // Tx Power in dBm.
 	CRC                      bool
 	// Low data rate optimisation flag. The use of this flag is mandated when
@@ -34,9 +34,9 @@ type Config struct {
 }
 
 // SymbolPeriod returns the time it takes to transmit a single symbol given the
-// current configuration parameters. It depends on Spread factor and Bandwidth.
+// current configuration parameters. It depends on Spreading factor and Bandwidth.
 func (cfg *Config) SymbolPeriod() time.Duration {
-	T_s := time.Second * time.Duration(cfg.SpreadFactor.ChipsPerSymbol()) /
+	T_s := time.Second * time.Duration(cfg.SpreadingFactor.ChipsPerSymbol()) /
 		time.Duration(cfg.Bandwidth.Hertz())
 	return T_s
 }
@@ -47,7 +47,7 @@ func (cfg *Config) SymbolPeriod() time.Duration {
 //   - CRC presence	(presence == longer)
 //   - Header type	(explicit == longer)
 //   - Coding rate	(proportional)
-//   - Spread factor	(inversely proportional)
+//   - Spreading factor	(inversely proportional)
 //   - Preamble length	(proportional)
 //   - Low data rate optimisation	(presence == longer)
 func (cfg *Config) TimeOnAir(payloadLength int) time.Duration {
@@ -58,10 +58,10 @@ func (cfg *Config) TimeOnAir(payloadLength int) time.Duration {
 	ih := int64(cfg.HeaderType)
 	ldr := int64(b2u8(cfg.LDRO))
 	cr := int64(cfg.CodingRate)
-	spread := int64(cfg.SpreadFactor)
+	sf := int64(cfg.SpreadingFactor)
 	// Page 31 SX1276IMLTRT SEMTECH | Alldatasheet.
-	Npayload := 8*int64(payloadLength) - 4*spread + 28 + 16*crc - 20*ih
-	div := 4 * (spread - 2*ldr)
+	Npayload := 8*int64(payloadLength) - 4*sf + 28 + 16*crc - 20*ih
+	div := 4 * (sf - 2*ldr)
 	// Apply Ceil and max with minimal branching.
 	if Npayload < 0 || div <= 0 {
 		Npayload = 0
@@ -77,7 +77,7 @@ func (cfg *Config) TimeOnAir(payloadLength int) time.Duration {
 	// time calculated.
 	Npayload += 8 + int64(cfg.PreambleLength) + 5
 	// Calculate LoRa Transmission Parameter Relationship page 28.
-	chipsPerSymbol := cfg.SpreadFactor.ChipsPerSymbol() // chips per symbol.
+	chipsPerSymbol := cfg.SpreadingFactor.ChipsPerSymbol() // chips per symbol.
 	return time.Second * time.Duration(Npayload*int64(chipsPerSymbol)) /
 		time.Duration(cfg.Bandwidth.Hertz())
 }
@@ -110,15 +110,16 @@ const (
 	CR4_8 CodingRate = 4
 )
 
-// SpreadFactor defines the number of chips per symbol. Higher spread factors
+// SpreadingFactor defines the number of chips per symbol. Higher spreading factors
 // imply longer transmission times but more robust communications.
-// The number of chips per symbol is 2^SF, so a spread factor of 8 takes twice
-// as long to transmit a symbol as a spread factor of 7.
-type SpreadFactor uint8
+// The number of chips per symbol is 2^SF, so a spreading factor of 8 takes twice
+// as long to transmit a symbol as a spreading factor of 7.
+type SpreadingFactor uint8
 
-// Common spread factors. Decide the number of chips per symbol.
+// Common spreading factors. Decide the number of chips per symbol.
 const (
-	SF6 SpreadFactor = iota + 6
+	SF5 SpreadingFactor = iota + 5
+	SF6
 	SF7
 	SF8
 	SF9
@@ -129,9 +130,9 @@ const (
 
 // ChipsPerSymbol returns the number of chips in a symbol. A chip is a subdivision
 // of a symbol in the frequency domain rather than the time domain, which is why
-// the units of this value is Hz, not Duration. A chip tells tells where to start
+// the units of this value is Hz, not Duration. A chip tells where to start
 // the frequency sweep for a symbol.
-func (sf SpreadFactor) ChipsPerSymbol() int64 {
+func (sf SpreadingFactor) ChipsPerSymbol() int64 {
 	return 1 << sf
 }
 
@@ -161,6 +162,7 @@ const (
 	BW125k  = 125 * Kilohertz
 	BW250k  = 250 * Kilohertz
 	BW500k  = 500 * Kilohertz
+	BW1625k = 1625 * Kilohertz
 )
 
 // Common LoRa frequencies
@@ -173,6 +175,7 @@ const (
 	Freq868_5M  = 868500000 * Hertz
 	Freq916_8M  = 916800000 * Hertz
 	Freq923_3M  = 923300000 * Hertz
+	Freq2400_0M = 2400 * Megahertz
 )
 
 // 169.4MHz radio band ([Wize]), formerly known as ERMES band. Historically used by pagers.

lora_test.go

@@ -24,7 +24,7 @@ func TestTimeOnAir(t *testing.T) {
 			cfg: lora.Config{
 				Bandwidth:       lora.BW125k,
 				Frequency:       915e6,
-				SpreadFactor:   lora.SF7,
+				SpreadingFactor: lora.SF7,
 				HeaderType:      lora.HeaderExplicit,
 				CodingRate:      loraWANCodeRate,
 				CRC:             true,
@@ -38,7 +38,7 @@ func TestTimeOnAir(t *testing.T) {
 			cfg: lora.Config{
 				Bandwidth:       lora.BW500k,
 				Frequency:       915e6,
-				SpreadFactor:   lora.SF7,
+				SpreadingFactor: lora.SF7,
 				HeaderType:      lora.HeaderExplicit,
 				CodingRate:      loraWANCodeRate,
 				CRC:             true,

sx127x/sx127x.go

@@ -81,7 +81,7 @@ type DeviceLoRa struct {
 func DefaultConfig(freq lora.Frequency) lora.Config {
 	return lora.Config{
 		Frequency:                freq,
-		SpreadFactor:             lora.SF7,
+		SpreadingFactor:          lora.SF7,
 		Bandwidth:                lora.BW125k,
 		CodingRate:               lora.CR4_5,
 		PreambleLength:           8,
@@ -103,7 +103,7 @@ func NewLoRa(bus SPI, cs, reset PinOutput) *DeviceLoRa {
 }
 
 var (
-	errBadSpread              = errors.New("bad spread factor")
+	errBadSpreadingFactor     = errors.New("bad spreading factor")
 	errSF6Implicit            = errors.New("SF6 can only be used with implicit header type") // Page 30: Implicit Header Mode.
 	errPreambleTooShort       = errors.New("preamble length too short")
 	ErrNotDetected            = errors.New("sx127x not detected")
@@ -116,6 +116,7 @@ var (
 	ErrCRC                    = errors.New("crc error")
 	ErrRxTimeout              = errors.New("rx timeout")
 	errImplicitPacketTooLarge = errors.New("packet length exceeds MaxImplicitPayloadLength")
+	errSyncWordTooLarge       = errors.New("sync word too long")
 )
 
 func (d *DeviceLoRa) InitLoRaMode() (err error) {
@@ -139,9 +140,9 @@ func (d *DeviceLoRa) InitLoRaMode() (err error) {
 
 func (d *DeviceLoRa) Configure(cfg lora.Config) (err error) {
 	switch {
-	case cfg.SpreadFactor < lora.SF6 || cfg.SpreadFactor > lora.SF12:
-		err = errBadSpread
-	case cfg.SpreadFactor == lora.SF6 && cfg.HeaderType != lora.HeaderImplicit:
+	case cfg.SpreadingFactor < lora.SF6 || cfg.SpreadingFactor > lora.SF12:
+		err = errBadSpreadingFactor
+	case cfg.SpreadingFactor == lora.SF6 && cfg.HeaderType != lora.HeaderImplicit:
 		err = errSF6Implicit
 	case cfg.PreambleLength < 6:
 		err = errPreambleTooShort
@@ -156,6 +157,8 @@ func (d *DeviceLoRa) Configure(cfg lora.Config) (err error) {
 		err = errors.New("MaxImplicitPayloadLength parameter must be set when working with implicit headers")
 	case cfg.TxPower > 20 || cfg.TxPower < -4:
 		err = errors.New("tx power not in operating range -4..20")
+	case cfg.SyncWord > 0xff:
+		err = errSyncWordTooLarge
 	}
 	if err != nil {
 		return err
@@ -189,7 +192,7 @@ func (d *DeviceLoRa) Configure(cfg lora.Config) (err error) {
 		return err
 	}
 	// TODO(soypat): Use default OCP?
-	err = d.setSyncWord(cfg.SyncWord)
+	err = d.setSyncWord(uint8(cfg.SyncWord))
 	if err != nil {
 		return err
 	}
@@ -197,7 +200,7 @@ func (d *DeviceLoRa) Configure(cfg lora.Config) (err error) {
 	if err != nil {
 		return err
 	}
-	err = d.setSpreadFactorConsistent(cfg.SpreadFactor)
+	err = d.setSpreadingFactorConsistent(cfg.SpreadingFactor)
 	if err != nil {
 		return err
 	}
@@ -706,7 +709,7 @@ func (d *DeviceLoRa) ReadConfig() (cfg lora.Config, err error) {
 	cfg.CodingRate = lora.CodingRate(cfg1>>1) & 0b111
 	cfg.HeaderType = lora.HeaderType(cfg1 & 1)
 	cfg2 := buf[1]
-	cfg.SpreadFactor = lora.SpreadFactor(cfg1 >> 4)
+	cfg.SpreadingFactor = lora.SpreadingFactor(cfg1 >> 4)
 	cfg.CRC = cfg2&0x4 != 0
 	// continuousMode = cfg2&0x8 != 0
 	cfg.PreambleLength = binary.BigEndian.Uint16(buf[3:])
@@ -715,7 +718,7 @@ func (d *DeviceLoRa) ReadConfig() (cfg lora.Config, err error) {
 	if err != nil {
 		return cfg, err
 	}
-	cfg.SyncWord = sync
+	cfg.SyncWord = uint16(sync)
 	// Read Frequency.
 	err = d.read(regFRF_MSB, buf[:3])
 	if err != nil {
@@ -864,9 +867,9 @@ func (d *DeviceLoRa) setFrequency(freq lora.Frequency) error {
 	return d.Write8(regFRF_LSB, freqReg[2]) // Write LSB last!
 }
 
-// setSpreadFactorConsistent sets the spreading factor and closely related parameters
+// setSpreadingFactorConsistent sets the spreading factor and closely related parameters
 // including Low Data Rate Optimization, DetectionOptimize, and DetectionThreshold.
-func (d *DeviceLoRa) setSpreadFactorConsistent(sf lora.SpreadFactor) (err error) {
+func (d *DeviceLoRa) setSpreadingFactorConsistent(sf lora.SpreadingFactor) (err error) {
 	err = d.setSpreadingFactor(sf)
 	if err != nil {
 		return err
@@ -889,9 +892,9 @@ func (d *DeviceLoRa) setSpreadFactorConsistent(sf lora.SpreadFactor) (err error)
 // It does not set parameters closely associated with the spreading factor such as
 // the Low Data Optimization, the Detection threshold, Detection Optimize and the
 // Symbol Timeout.
-func (d *DeviceLoRa) setSpreadingFactor(sf lora.SpreadFactor) error {
+func (d *DeviceLoRa) setSpreadingFactor(sf lora.SpreadingFactor) error {
 	if sf < 6 || sf > 12 {
-		return errBadSpread
+		return errBadSpreadingFactor
 	}
 	const sfMask = 0b111 << 4
 	return d.writeMasked8(regMODEM_CONFIG_2, sfMask, uint8(sf)<<4)

sx128x/commands.go

@@ -0,0 +1,43 @@
+package sx128x
+
+const (
+	// SX128X SPI commands
+	cmdGetStatus = uint8(0xC0)
+
+	// Register Access Operations
+	cmdWriteRegister = uint8(0x18)
+	cmdReadRegister  = uint8(0x19)
+
+	// Data Buffer Operations
+	cmdWriteBuffer = uint8(0x1A)
+	cmdReadBuffer  = uint8(0x1B)
+
+	// Radio Operation Modes
+	cmdSetSleep   = uint8(0x84)
+	cmdSetStandby = uint8(0x80)
+	cmdSetTx      = uint8(0x83)
+	cmdSetRx      = uint8(0x82)
+
+	// Radio Configuration
+	cmdSetPacketType        = uint8(0x8A)
+	cmdGetPacketType        = uint8(0x03)
+	cmdSetRFFrequency       = uint8(0x86)
+	cmdSetTxParams          = uint8(0x8E)
+	cmdSetBufferBaseAddress = uint8(0x8F)
+	cmdSetModulationParams  = uint8(0x8B)
+	cmdSetPacketParams      = uint8(0x8C)
+
+	// Communication Status Information
+	cmdGetRxBufferStatus = uint8(0x17)
+	cmdGetPacketStatus   = uint8(0x1D)
+	cmdGetRSSIInst       = uint8(0x1F)
+
+	// IRQ Handling
+	cmdSetDIOIRQParams = uint8(0x8D)
+	cmdGetIRQStatus    = uint8(0x15)
+	cmdClearIRQStatus  = uint8(0x97)
+
+	// Miscellaneous
+	cmdSetRegulatorMode = uint8(0x96)
+	cmdSetSaveContext   = uint8(0xD5)
+)

sx128x/constants.go

@@ -0,0 +1,67 @@
+package sx128x
+
+type standbyConfig uint8
+type periodBase uint8
+type packetType uint8
+type radioRampTime uint8
+
+// Misc
+type irqMask uint16
+
+const (
+
+	// StandbyConfig
+	standbyRC   = standbyConfig(0)
+	standbyXOSC = standbyConfig(1)
+
+	// PeriodBase
+	periodBase4Ms = periodBase(3)
+
+	// PacketType
+	packetTypeLoRa = packetType(0x01)
+	packetTypeBLE  = packetType(0x04)
+
+	// RampTime
+	radioRamp02us = radioRampTime(0x00)
+	radioRamp04us = radioRampTime(0x20)
+	radioRamp06us = radioRampTime(0x40)
+	radioRamp08us = radioRampTime(0x60)
+	radioRamp10us = radioRampTime(0x80)
+	radioRamp12us = radioRampTime(0xA0)
+	radioRamp16us = radioRampTime(0xC0)
+	radioRamp20us = radioRampTime(0xE0)
+
+	// LoRa Modulation Params
+	loraBW1600 = byte(0x0A)
+	loraBW800  = byte(0x18)
+	loraBW400  = byte(0x26)
+	loraBW200  = byte(0x34)
+
+	// CodingRate
+	loraCR4_5    = byte(0x01)
+	loraCR4_6    = byte(0x02)
+	loraCR4_7    = byte(0x03)
+	loraCR4_8    = byte(0x04)
+	loraCRLI_4_5 = byte(0x05)
+	loraCRLI_4_6 = byte(0x06)
+	loraCRLI_4_8 = byte(0x07)
+
+	// LoraPacketParams
+	// HeaderType
+	loraHeaderExplicit = byte(0x00)
+	loraHeaderImplicit = byte(0x80)
+
+	// CRC Type
+	loraCRCEnable  = byte(0x20)
+	loraCRCDisable = byte(0x00)
+
+	// IQ Type
+	loraIQInverted = byte(0x00)
+	loraIQStandard = byte(0x40)
+
+	// IRQ masks
+	irqAll     = irqMask(0xFFFF)
+	irqTxDone  = irqMask(0b0000000000000001)
+	irqRxDone  = irqMask(0b0000000000000010)
+	irqTimeout = irqMask(0b0100000000000000)
+)

sx128x/errors.go

@@ -0,0 +1,20 @@
+package sx128x
+
+import "errors"
+
+var (
+	ErrBusyPinTimeout        = errors.New("busy pin timeout")
+	errDataTooLong           = errors.New("data over 256 bytes")
+	errInvalidStandbyConfig  = errors.New("invalid standby config")
+	errFrequencyTooLow       = errors.New("frequency below 2.4Ghz")
+	errFrequencyTooHigh      = errors.New("frequency above 2.5Ghz")
+	errPowerTooLow           = errors.New("power level below -18dBm")
+	errPowerTooHigh          = errors.New("power level above 13dBm")
+	errInvalidPeriodBase     = errors.New("invalid period base")
+	errInvalidPacketType     = errors.New("invalid packet type")
+	errInvalidHeaderType     = errors.New("invalid header type")
+	errInvalidBandwidth      = errors.New("invalid bandwidth")
+	errInvalidCodingRate     = errors.New("invalid coding rate")
+	errPayloadLengthTooShort = errors.New("payload length too short")
+	errRxTimeout             = errors.New("rx timeout")
+)

sx128x/registers.go

@@ -0,0 +1,8 @@
+package sx128x
+
+const (
+	regSpreadingFactorAdditionalConfiguration = uint16(0x925)
+	regFrequencyErrorCorrection               = uint16(0x93C)
+	regLoRaSyncWordMSB                        = uint16(0x944)
+	regLoRaSyncWordLSB                        = uint16(0x945)
+)

sx128x/sx128x.go

@@ -0,0 +1,580 @@
+package sx128x
+
+import (
+	"errors"
+	"io"
+	"runtime"
+	"time"
+
+	"github.com/soypat/lora"
+)
+
+type Output func(bool)
+type Input func() bool
+
+type SPI interface {
+	Transfer(w byte) (byte, error)
+	Tx(writeBuffer, readBuffer []byte) error
+}
+
+type DeviceLoRa struct {
+	spi      SPI
+	cs       Output
+	rst      Output
+	busy     Input
+	dio1     Input
+	spiTxBuf []byte
+	spiRxBuf []byte
+	config   lora.Config
+}
+
+func DefaultConfig(freq lora.Frequency) lora.Config {
+	return lora.Config{
+		Frequency:                freq,
+		SpreadingFactor:          lora.SF9,
+		Bandwidth:                lora.BW1625k,
+		CodingRate:               lora.CR4_5,
+		PreambleLength:           12,
+		HeaderType:               lora.HeaderExplicit,
+		MaxImplicitPayloadLength: 0, // No need to be set when working with explicit headers.
+		CRC:                      true,
+		SyncWord:                 0x1424,
+		TxPower:                  2,     // Low power by default.
+		LDRO:                     false, // not available on sx128x
+		IQInversion:              false,
+	}
+}
+
+func NewLoRa(spi SPI, cs Output, rst Output, busy Input, dio1 Input) *DeviceLoRa {
+	return &DeviceLoRa{
+		spi:      spi,
+		cs:       cs,
+		rst:      rst,
+		busy:     busy,
+		dio1:     dio1,
+		spiTxBuf: make([]byte, 256), // TODO: optimize buffer size
+		spiRxBuf: make([]byte, 256),
+	}
+}
+
+func (d *DeviceLoRa) Configure(config lora.Config) error {
+	switch {
+	case config.Frequency < 2400*lora.Megahertz:
+		return errFrequencyTooLow
+	case config.Frequency > 2500*lora.Megahertz:
+		return errFrequencyTooHigh
+	case config.TxPower < -18:
+		return errPowerTooLow
+	case config.TxPower > 13:
+		return errPowerTooHigh
+	case config.HeaderType != lora.HeaderExplicit && config.HeaderType != lora.HeaderImplicit:
+		return errInvalidHeaderType
+	case config.Bandwidth != lora.BW1625k:
+		return errInvalidBandwidth
+	case config.CodingRate != lora.CR4_5 && config.CodingRate != lora.CR4_6 && config.CodingRate != lora.CR4_7 && config.CodingRate != lora.CR4_8:
+		return errInvalidCodingRate
+	}
+	d.Reset()
+	d.config = config
+	// Switch to standby prior to configuration changes
+	err := d.setStandby(standbyRC)
+	if err != nil {
+		return err
+	}
+	// Clear errors, disable radio interrupts for the moment
+	err = d.setPacketType(packetTypeLoRa)
+	if err != nil {
+		return err
+	}
+	err = d.setRfFrequency(config.Frequency)
+	if err != nil {
+		return err
+	}
+	err = d.setModulationParamsLoRa(config.SpreadingFactor, config.Bandwidth, config.CodingRate)
+	if err != nil {
+		return err
+	}
+
+	// special register setting depending on spreading factor chosen
+	switch config.SpreadingFactor {
+	case lora.SF5, lora.SF6:
+		d.writeRegister(regSpreadingFactorAdditionalConfiguration, []byte{0x1E})
+	case lora.SF7, lora.SF8:
+		d.writeRegister(regSpreadingFactorAdditionalConfiguration, []byte{0x37})
+	default:
+		d.writeRegister(regSpreadingFactorAdditionalConfiguration, []byte{0x32})
+	}
+	d.writeRegister(regFrequencyErrorCorrection, []byte{0x01})
+
+	// TODO(jwetzell): hardcoded radio ramp
+	err = d.setTxParams(config.TxPower, radioRamp02us)
+	if err != nil {
+		return err
+	}
+	err = d.setPacketParamsLoRa(uint32(config.PreambleLength), config.HeaderType, 0xFF, config.CRC, config.IQInversion)
+	if err != nil {
+		return err
+	}
+	var syncWord [2]uint8
+	syncWord[0] = uint8(config.SyncWord >> 8)
+	syncWord[1] = uint8(config.SyncWord & 0x00FF)
+
+	err = d.writeRegister(regLoRaSyncWordMSB, syncWord[:])
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (d *DeviceLoRa) Tx(data []byte) error {
+	if len(data) > 255 {
+		return errors.New("data length exceeds maximum of 255 bytes")
+	}
+
+	// TODO(jwetzell): check chip status prior to setting Rx mode and return error if not ready
+	d.setStandby(standbyRC)
+	d.setPacketParamsLoRa(uint32(d.config.PreambleLength), d.config.HeaderType, uint8(len(data)&0xFF), d.config.CRC, d.config.IQInversion)
+	d.setBufferBaseAddress(0, 0)
+	d.writeBuffer(0, data)
+	d.setDioIrqParams(irqTxDone|irqTimeout, irqTxDone|irqTimeout, 0x00, 0x00)
+	d.clearIrqStatus(irqAll)
+	d.setTx(periodBase4Ms, 250) // fixed timeout for now
+	for {
+		if d.dio1() {
+			irqStatus, err := d.getIrqStatus()
+			if err != nil {
+				return err
+			}
+			if irqStatus&irqTimeout != 0 {
+				return errRxTimeout
+			}
+			if irqStatus&irqTxDone != 0 {
+				return nil
+			}
+		}
+	}
+}
+
+func (d *DeviceLoRa) RxSingle(dst []byte) (uint8, error) {
+	if len(dst) < 255 {
+		return 0, io.ErrShortBuffer
+	}
+	// TODO(jwetzell): check chip status prior to setting Rx mode and return error if not ready
+	d.setStandby(standbyRC)
+	d.setDioIrqParams(irqRxDone|irqTimeout, irqRxDone|irqTimeout, 0x00, 0x00)
+	d.setBufferBaseAddress(0, 0)
+	d.clearIrqStatus(irqAll)
+	d.setRx(periodBase4Ms, 250) // fixed timeout for now
+	for {
+		if d.dio1() {
+			irqStatus, err := d.getIrqStatus()
+			if err != nil {
+				return 0, err
+			}
+			if irqStatus&irqTimeout != 0 {
+				return 0, errRxTimeout
+			}
+			if irqStatus&irqRxDone != 0 {
+				payloadLength, offset, err := d.getRxBufferStatus()
+				if err != nil {
+					return 0, err
+				}
+				data, err := d.readBuffer(offset, payloadLength)
+				if err != nil {
+					return 0, err
+				}
+				copy(dst, data)
+				return payloadLength, nil
+			}
+		}
+	}
+}
+
+func (d *DeviceLoRa) Reset() {
+	d.rst(true)
+	time.Sleep(10 * time.Millisecond)
+	d.rst(false)
+	time.Sleep(10 * time.Millisecond)
+	d.rst(true)
+	time.Sleep(10 * time.Millisecond)
+	d.cs(false)
+}
+
+func (d *DeviceLoRa) waitWhileBusy(timeout time.Duration) error {
+	// largest busy period is on boot with around ~400ish this should be more than enough
+	now := time.Now()
+	for d.busy() {
+		if time.Since(now) > timeout {
+			return ErrBusyPinTimeout
+		}
+		runtime.Gosched()
+	}
+	return nil
+}
+
+func (d *DeviceLoRa) writeRegister(addr uint16, data []byte) error {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdWriteRegister, uint8((addr>>8)&0xFF), uint8(addr&0xFF))
+	d.spiTxBuf = append(d.spiTxBuf, data...)
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+func (d *DeviceLoRa) readRegister(addr uint16) (uint8, error) {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return 0, err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdReadRegister, uint8((addr&0xFF00)>>8), uint8(addr&0x00FF), 0x00, 0x00)
+	d.spiRxBuf = d.spiRxBuf[:5]
+	err = d.spi.Tx(d.spiTxBuf, d.spiRxBuf)
+	d.cs(true)
+	if err != nil {
+		return 0, err
+	}
+	return d.spiRxBuf[4], nil
+}
+
+func (d *DeviceLoRa) writeBuffer(offset uint8, data []byte) error {
+	if len(data) > 256 {
+		return errDataTooLong
+	}
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdWriteBuffer, offset)
+	d.spiTxBuf = append(d.spiTxBuf, data...)
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Read data from the payload buffer starting at the given offset with the given length
+func (d *DeviceLoRa) readBuffer(offset uint8, length uint8) ([]byte, error) {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return nil, err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdReadBuffer, offset, 0x00)
+	for i := uint8(0); i < length; i++ {
+		d.spiTxBuf = append(d.spiTxBuf, 0x00)
+	}
+	d.spiRxBuf = d.spiRxBuf[:len(d.spiTxBuf)]
+	err = d.spi.Tx(d.spiTxBuf, d.spiRxBuf)
+	d.cs(true)
+	if err != nil {
+		return nil, err
+	}
+	return d.spiRxBuf[3 : 3+length], nil
+}
+
+// Put device into standby mode, 0 (RC) or 1 (XOSC)
+func (d *DeviceLoRa) setStandby(standbyConfig standbyConfig) error {
+	if standbyConfig > standbyXOSC { // XOSC is the highest standby config anything higher is invalid
+		return errInvalidStandbyConfig
+	}
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetStandby, uint8(standbyConfig))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+func checkPeriodBase(periodBase periodBase) error {
+	if periodBase > periodBase4Ms { // 4ms is the highest period base anything higher is invalid
+		return errInvalidPeriodBase
+	}
+	return nil
+}
+
+// Sets the device in transmit mode, the IRQ status should be cleared before using this command
+// timout is determined by periodBase * periodBaseCount
+func (d *DeviceLoRa) setTx(periodBase periodBase, periodBaseCount uint16) error {
+	err := checkPeriodBase(periodBase)
+	if err != nil {
+		return err
+	}
+	err = d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetTx, uint8(periodBase), uint8((periodBaseCount>>8)&0xFF), uint8(periodBaseCount&0xFF))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Sets the device in receive mode, the IRQ status should be cleared before using this command
+// timeout is determined by periodBase * periodBaseCount
+func (d *DeviceLoRa) setRx(periodBase periodBase, periodBaseCount uint16) error {
+	err := checkPeriodBase(periodBase)
+	if err != nil {
+		return err
+	}
+	err = d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetRx, uint8(periodBase), uint8((periodBaseCount>>8)&0xFF), uint8(periodBaseCount&0xFF))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Choose between GFSK, LoRa, Ranging, FLRC or BLE packet types, this will affect the available configuration parameters and the structure of the packet
+func (d *DeviceLoRa) setPacketType(packetType packetType) error {
+	if packetType > packetTypeBLE { // BLE is the highest packet type anything higher is invalid.
+		return errInvalidPacketType
+	}
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetPacketType, uint8(packetType))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Set the RF frequency in Hz, must be between 2.4 GHz and 2.5 GHz
+func (d *DeviceLoRa) setRfFrequency(frequencyHz lora.Frequency) error {
+	if frequencyHz < 2400000000 {
+		return errFrequencyTooLow
+	}
+	if frequencyHz > 2500000000 {
+		return errFrequencyTooHigh
+	}
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	rfFrequency := uint32((uint64(frequencyHz) << 18) / 52000000)
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetRFFrequency, uint8((rfFrequency>>16)&0xFF), uint8((rfFrequency>>8)&0xFF), uint8(rfFrequency&0xFF))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Set the output power in dBm, must be between -18 and 13 dBm, and the ramp time
+func (d *DeviceLoRa) setTxParams(powerdBm int8, rampTime radioRampTime) error {
+	if powerdBm < -18 {
+		return errPowerTooLow
+	}
+	if powerdBm > 13 {
+		return errPowerTooHigh
+	}
+
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	adjustedPower := uint8(powerdBm + 18)
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetTxParams, adjustedPower, uint8(rampTime))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Set the base address for the internal buffer for Tx and Rx operations.
+// When transmitting or receiving data is read from or written to the buffer starting at the given offset.
+func (d *DeviceLoRa) setBufferBaseAddress(txBase uint8, rxBase uint8) error {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetBufferBaseAddress, txBase, rxBase)
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+func (d *DeviceLoRa) setModulationParamsLoRa(spreadingFactor lora.SpreadingFactor, bandwidth lora.Frequency, codingRate lora.CodingRate) error {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetModulationParams) //, uint8(spreadingFactor), uint8(bandwidth), uint8(codingRate))
+	d.spiTxBuf = append(d.spiTxBuf, uint8(spreadingFactor<<4))
+	switch bandwidth {
+	case lora.BW1625k:
+		d.spiTxBuf = append(d.spiTxBuf, loraBW1600)
+	// TODO(jwetzell): support for other bandwidths
+	default:
+		return errInvalidBandwidth
+	}
+	switch codingRate {
+	case lora.CR4_5:
+		d.spiTxBuf = append(d.spiTxBuf, loraCR4_5)
+	case lora.CR4_6:
+		d.spiTxBuf = append(d.spiTxBuf, loraCR4_6)
+	case lora.CR4_7:
+		d.spiTxBuf = append(d.spiTxBuf, loraCR4_7)
+	case lora.CR4_8:
+		d.spiTxBuf = append(d.spiTxBuf, loraCR4_8)
+	// TODO(jwetzell): support for LI coding rates
+	default:
+		return errInvalidCodingRate
+	}
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Set LoRa related packet parameters, this assumes the packet type is already set to LoRa.
+// - payloadLength: range of 1-255
+func (d *DeviceLoRa) setPacketParamsLoRa(preambleLength uint32, headerType lora.HeaderType, payloadLength uint8, crcEnabled bool, iqInversion bool) error {
+	if payloadLength == 0 {
+		return errPayloadLengthTooShort
+	}
+	exponent, mantissa := getExponentAndMantissa(preambleLength)
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetPacketParams, uint8(exponent<<4)|mantissa)
+	switch headerType {
+	case lora.HeaderExplicit:
+		d.spiTxBuf = append(d.spiTxBuf, loraHeaderExplicit)
+	case lora.HeaderImplicit:
+		d.spiTxBuf = append(d.spiTxBuf, loraHeaderImplicit)
+	default:
+		return errInvalidHeaderType
+	}
+	d.spiTxBuf = append(d.spiTxBuf, payloadLength)
+	if crcEnabled {
+		d.spiTxBuf = append(d.spiTxBuf, loraCRCEnable)
+	} else {
+		d.spiTxBuf = append(d.spiTxBuf, loraCRCDisable)
+	}
+	if iqInversion {
+		d.spiTxBuf = append(d.spiTxBuf, loraIQInverted)
+	} else {
+		d.spiTxBuf = append(d.spiTxBuf, loraIQStandard)
+	}
+	d.spiTxBuf = append(d.spiTxBuf, 0, 0) // unused parameters
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+func getExponentAndMantissa(value uint32) (uint8, uint8) {
+	// pulled from RadioLib https://github.com/jgromes/RadioLib/blob/master/src/modules/SX128x/cpp
+	e := uint8(1)
+	m := uint8(1)
+	len := uint32(0)
+	for e = uint8(1); e <= 15; e++ {
+		for m = uint8(1); m <= 15; m++ {
+			len = uint32(m) * (uint32(1 << e))
+			if len >= value {
+				break
+			}
+		}
+		if len >= value {
+			break
+		}
+	}
+
+	return e, m
+}
+
+// Get information about the most recent packet received.
+// Return the payload length, the offset in the buffer where the payload starts.
+func (d *DeviceLoRa) getRxBufferStatus() (uint8, uint8, error) {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return 0, 0, err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdGetRxBufferStatus, 0x00, 0x00, 0x00)
+	d.spiRxBuf = d.spiRxBuf[:4]
+	err = d.spi.Tx(d.spiTxBuf, d.spiRxBuf)
+	d.cs(true)
+	if err != nil {
+		return 0, 0, err
+	}
+	return d.spiRxBuf[2], d.spiRxBuf[3], nil
+}
+
+// Configure the overall IRQ mask and the mapping of individual IRQs to the DIO1, DIO2 and DIO3 pins
+func (d *DeviceLoRa) setDioIrqParams(irqMask irqMask, dio1Mask irqMask, dio2Mask irqMask, dio3Mask irqMask) error {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdSetDIOIRQParams, uint8((irqMask&0xFF00)>>8), uint8(irqMask&0x00FF))
+	d.spiTxBuf = append(d.spiTxBuf, uint8((dio1Mask&0xFF00)>>8), uint8(dio1Mask&0x00FF))
+	d.spiTxBuf = append(d.spiTxBuf, uint8((dio2Mask&0xFF00)>>8), uint8(dio2Mask&0x00FF))
+	d.spiTxBuf = append(d.spiTxBuf, uint8((dio3Mask&0xFF00)>>8), uint8(dio3Mask&0x00FF))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}
+
+// Get the current IRQ status.
+func (d *DeviceLoRa) getIrqStatus() (irqMask, error) {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return 0, err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdGetIRQStatus, 0x00, 0x00, 0x00)
+	d.spiRxBuf = d.spiRxBuf[:4]
+	err = d.spi.Tx(d.spiTxBuf, d.spiRxBuf)
+	d.cs(true)
+	if err != nil {
+		return 0, err
+	}
+	return irqMask(uint16(d.spiRxBuf[2])<<8 | uint16(d.spiRxBuf[3])), err
+}
+
+// Clear the IRQ bits specified in the irqMask.
+func (d *DeviceLoRa) clearIrqStatus(irqMask irqMask) error {
+	err := d.waitWhileBusy(time.Second)
+	if err != nil {
+		return err
+	}
+	d.cs(false)
+	d.spiTxBuf = d.spiTxBuf[:0]
+	d.spiTxBuf = append(d.spiTxBuf, cmdClearIRQStatus, uint8((irqMask&0xFF00)>>8), uint8(irqMask&0x00FF))
+	err = d.spi.Tx(d.spiTxBuf, nil)
+	d.cs(true)
+	return err
+}