Arduino-nano33 - TinyGo

arduino-nano33

Constants

const ( RX0 Pin = PB23 // UART2 RX TX1 Pin = PB22 // UART2 TX D2 Pin = PB10 // PWM available D3 Pin = PB11 // PWM available D4 Pin = PA07 D5 Pin = PA05 // PWM available D6 Pin = PA04 // PWM available D7 Pin = PA06 D8 Pin = PA18 D9 Pin = PA20 // PWM available D10 Pin = PA21 // PWM available D11 Pin = PA16 // PWM available D12 Pin = PA19 // PWM available D13 Pin = PA17 )

GPIO Pins

const ( A0 Pin = PA02 // ADC/AIN[0] A1 Pin = PB02 // ADC/AIN[10] A2 Pin = PA11 // ADC/AIN[19] A3 Pin = PA10 // ADC/AIN[18], A4 Pin = PB08 // ADC/AIN[2], SCL: SERCOM2/PAD[1] A5 Pin = PB09 // ADC/AIN[3], SDA: SERCOM2/PAD[1] A6 Pin = PA09 // ADC/AIN[17] A7 Pin = PB03 // ADC/AIN[11] )

Analog pins

const ( LED = D13 ) const ( USBCDC_DM_PIN Pin = PA24 USBCDC_DP_PIN Pin = PA25 )

USBCDC pins

const ( UART_TX_PIN Pin = PA22 UART_RX_PIN Pin = PA23 )

UART1 pins

const ( SDA_PIN Pin = A4 // SDA: SERCOM4/PAD[1] SCL_PIN Pin = A5 // SCL: SERCOM4/PAD[1] )

I2C pins

const ( SPI0_SCK_PIN Pin = D13 // SCK: SERCOM1/PAD[1] SPI0_SDO_PIN Pin = D11 // SDO: SERCOM1/PAD[0] SPI0_SDI_PIN Pin = D12 // SDI: SERCOM1/PAD[3] )

SPI pins

const ( NINA_SDO Pin = PA12 NINA_SDI Pin = PA13 NINA_CS Pin = PA14 NINA_SCK Pin = PA15 NINA_GPIO0 Pin = PA27 NINA_RESETN Pin = PA08 NINA_ACK Pin = PA28 NINA_TX Pin = PA12 NINA_RX Pin = PA13 NINA_RTS Pin = PA14 NINA_CTS Pin = PA15 )

NINA-W102 Pins

const ( NINA_BAUDRATE = 912600 NINA_RESET_INVERTED = true NINA_SOFT_FLOWCONTROL = false )

NINA-W102 settings

const ( I2S_SCK_PIN Pin = PA10 I2S_SDO_PIN Pin = PA08 I2S_SDI_PIN = NoPin I2S_WS_PIN = NoPin // TODO: figure out what this is on Arduino Nano 33. )

I2S pins

const ( PA00 Pin = 0 // peripherals: TCC2 channel 0, sercomI2CM1 SDA PA01 Pin = 1 // peripherals: TCC2 channel 1, sercomI2CM1 SCL PA02 Pin = 2 PA03 Pin = 3 PA04 Pin = 4 // peripherals: TCC0 channel 0 PA05 Pin = 5 // peripherals: TCC0 channel 1 PA06 Pin = 6 // peripherals: TCC1 channel 0 PA07 Pin = 7 // peripherals: TCC1 channel 1 PA08 Pin = 8 // peripherals: TCC0 channel 0, TCC1 channel 2, sercomI2CM0 SDA, sercomI2CM2 SDA PA09 Pin = 9 // peripherals: TCC0 channel 1, TCC1 channel 3, sercomI2CM0 SCL, sercomI2CM2 SCL PA10 Pin = 10 // peripherals: TCC1 channel 0, TCC0 channel 2 PA11 Pin = 11 // peripherals: TCC1 channel 1, TCC0 channel 3 PA12 Pin = 12 // peripherals: TCC2 channel 0, TCC0 channel 2, sercomI2CM2 SDA, sercomI2CM4 SDA PA13 Pin = 13 // peripherals: TCC2 channel 1, TCC0 channel 3, sercomI2CM2 SCL, sercomI2CM4 SCL PA14 Pin = 14 // peripherals: TCC0 channel 0 PA15 Pin = 15 // peripherals: TCC0 channel 1 PA16 Pin = 16 // peripherals: TCC2 channel 0, TCC0 channel 2, sercomI2CM1 SDA, sercomI2CM3 SDA PA17 Pin = 17 // peripherals: TCC2 channel 1, TCC0 channel 3, sercomI2CM1 SCL, sercomI2CM3 SCL PA18 Pin = 18 // peripherals: TCC0 channel 2 PA19 Pin = 19 // peripherals: TCC0 channel 3 PA20 Pin = 20 // peripherals: TCC0 channel 2 PA21 Pin = 21 // peripherals: TCC0 channel 3 PA22 Pin = 22 // peripherals: TCC0 channel 0, sercomI2CM3 SDA, sercomI2CM5 SDA PA23 Pin = 23 // peripherals: TCC0 channel 1, sercomI2CM3 SCL, sercomI2CM5 SCL PA24 Pin = 24 // peripherals: TCC1 channel 2 PA25 Pin = 25 // peripherals: TCC1 channel 3 PA26 Pin = 26 PA27 Pin = 27 PA28 Pin = 28 PA29 Pin = 29 PA30 Pin = 30 // peripherals: TCC1 channel 0 PA31 Pin = 31 // peripherals: TCC1 channel 1 PB00 Pin = 32 PB01 Pin = 33 PB02 Pin = 34 // peripherals: sercomI2CM5 SDA PB03 Pin = 35 // peripherals: sercomI2CM5 SCL PB04 Pin = 36 PB05 Pin = 37 PB06 Pin = 38 PB07 Pin = 39 PB08 Pin = 40 // peripherals: sercomI2CM4 SDA PB09 Pin = 41 // peripherals: sercomI2CM4 SCL PB10 Pin = 42 // peripherals: TCC0 channel 0 PB11 Pin = 43 // peripherals: TCC0 channel 1 PB12 Pin = 44 // peripherals: TCC0 channel 2, sercomI2CM4 SDA PB13 Pin = 45 // peripherals: TCC0 channel 3, sercomI2CM4 SCL PB14 Pin = 46 PB15 Pin = 47 PB16 Pin = 48 // peripherals: TCC0 channel 0, sercomI2CM5 SDA PB17 Pin = 49 // peripherals: TCC0 channel 1, sercomI2CM5 SCL PB18 Pin = 50 PB19 Pin = 51 PB20 Pin = 52 PB21 Pin = 53 PB22 Pin = 54 PB23 Pin = 55 PB24 Pin = 56 PB25 Pin = 57 PB26 Pin = 58 PB27 Pin = 59 PB28 Pin = 60 PB29 Pin = 61 PB30 Pin = 62 // peripherals: TCC0 channel 0, TCC1 channel 2, sercomI2CM5 SDA PB31 Pin = 63 // peripherals: TCC0 channel 1, TCC1 channel 3, sercomI2CM5 SCL )

Hardware pins

const ( TWI_FREQ_100KHZ = 100000 TWI_FREQ_400KHZ = 400000 )

TWI_FREQ is the I2C bus speed. Normally either 100 kHz, or 400 kHz for high-speed bus.

Deprecated: use 100 * machine.KHz or 400 * machine.KHz instead.

const ( // I2CReceive indicates target has received a message from the controller. I2CReceive I2CTargetEvent = iota // I2CRequest indicates the controller is expecting a message from the target. I2CRequest // I2CFinish indicates the controller has ended the transaction. // // I2C controllers can chain multiple receive/request messages without // relinquishing the bus by doing 'restarts'. I2CFinish indicates the // bus has been relinquished by an I2C 'stop'. I2CFinish ) const ( // I2CModeController represents an I2C peripheral in controller mode. I2CModeController I2CMode = iota // I2CModeTarget represents an I2C peripheral in target mode. I2CModeTarget ) const ( I2SModeSource I2SMode = iota I2SModeReceiver I2SModePDM I2SModeSourceReceiver ) const ( I2StandardPhilips I2SStandard = iota I2SStandardMSB I2SStandardLSB ) const ( I2SClockSourceInternal I2SClockSource = iota I2SClockSourceExternal ) const ( I2SDataFormatDefault I2SDataFormat = 0 I2SDataFormat8bit = 8 I2SDataFormat16bit = 16 I2SDataFormat24bit = 24 I2SDataFormat32bit = 32 ) const Device = deviceName

Device is the running program’s chip name, such as “ATSAMD51J19A” or “nrf52840”. It is not the same as the CPU name.

The constant is some hardcoded default value if the program does not target a particular chip but instead runs in WebAssembly for example.

const ( KHz = 1000 MHz = 1000_000 GHz = 1000_000_000 )

Generic constants.

const NoPin = Pin(0xff)

NoPin explicitly indicates “not a pin”. Use this pin if you want to leave one of the pins in a peripheral unconfigured (if supported by the hardware).

const ( PinAnalog PinMode = 1 PinSERCOM PinMode = 2 PinSERCOMAlt PinMode = 3 PinTimer PinMode = 4 PinTimerAlt PinMode = 5 PinCom PinMode = 6 //PinAC_CLK PinMode = 7 PinDigital PinMode = 8 PinInput PinMode = 9 PinInputPullup PinMode = 10 PinOutput PinMode = 11 PinTCC PinMode = PinTimer PinTCCAlt PinMode = PinTimerAlt PinInputPulldown PinMode = 12 ) const ( PinRising PinChange = sam.EIC_CONFIG_SENSE0_RISE PinFalling PinChange = sam.EIC_CONFIG_SENSE0_FALL PinToggle PinChange = sam.EIC_CONFIG_SENSE0_BOTH )

Pin change interrupt constants for SetInterrupt.

const ( // WatchdogMaxTimeout in milliseconds (16s) WatchdogMaxTimeout = (16384 * 1000) / 1024 ) const ( // these are SAMD21 specific. usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos = 0 usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask = 0x3FFF usb_DEVICE_PCKSIZE_SIZE_Pos = 28 usb_DEVICE_PCKSIZE_SIZE_Mask = 0x7 usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Pos = 14 usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Mask = 0x3FFF NumberOfUSBEndpoints = 8 ) const ( Mode0 = 0 Mode1 = 1 Mode2 = 2 Mode3 = 3 )

SPI phase and polarity configs CPOL and CPHA

const ( // ParityNone means to not use any parity checking. This is // the most common setting. ParityNone UARTParity = iota // ParityEven means to expect that the total number of 1 bits sent // should be an even number. ParityEven // ParityOdd means to expect that the total number of 1 bits sent // should be an odd number. ParityOdd )

Variables

var UART1 = &sercomUSART3

UART1 on the Arduino Nano 33 connects to the onboard NINA-W102 WiFi chip.

var UART2 = &sercomUSART5

UART2 on the Arduino Nano 33 connects to the normal TX/RX pins.

var UART_NINA = &sercomUSART2

UART_NINA on the Arduino Nano 33 connects to the NINA HCI.

var ( I2C0 = sercomI2CM4 )

I2C on the Arduino Nano 33.

var SPI0 = sercomSPIM1

SPI on the Arduino Nano 33.

var ( SPI1 = sercomSPIM2 NINA_SPI = SPI1 )

SPI1 is connected to the NINA-W102 chip on the Arduino Nano 33.

var ( ErrInvalidSampleFrequency = errors.New("i2s: invalid sample frequency") ) var ( ErrTimeoutRNG = errors.New("machine: RNG Timeout") ErrClockRNG = errors.New("machine: RNG Clock Error") ErrSeedRNG = errors.New("machine: RNG Seed Error") ErrInvalidInputPin = errors.New("machine: invalid input pin") ErrInvalidOutputPin = errors.New("machine: invalid output pin") ErrInvalidClockPin = errors.New("machine: invalid clock pin") ErrInvalidDataPin = errors.New("machine: invalid data pin") ErrNoPinChangeChannel = errors.New("machine: no channel available for pin interrupt") ) var I2S0 = I2S{Bus: sam.I2S} var ( TCC0 = (*TCC)(sam.TCC0) TCC1 = (*TCC)(sam.TCC1) TCC2 = (*TCC)(sam.TCC2) )

The SAM D21 has three TCC peripherals, which have PWM as one feature.

var ( DAC0 = DAC{} ) var Flash flashBlockDevice var Watchdog = &watchdogImpl{}

Watchdog provides access to the hardware watchdog available in the SAMD21.

var ( ErrPWMPeriodTooLong = errors.New("pwm: period too long") ) var Serial Serialer

Serial is implemented via USB (USB-CDC).

var ( ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size") errSPIInvalidMachineConfig = errors.New("SPI port was not configured properly by the machine") ) var ( USBDev = &USBDevice{} USBCDC Serialer ) var ( ErrUSBReadTimeout = errors.New("USB read timeout") ErrUSBBytesRead = errors.New("USB invalid number of bytes read") ErrUSBBytesWritten = errors.New("USB invalid number of bytes written") )

func AckUsbOutTransfer

func AckUsbOutTransfer(ep uint32)

AckUsbOutTransfer is called to acknowledge the completion of a USB OUT transfer.

func CPUFrequency

func CPUFrequency() uint32

Return the current CPU frequency in hertz.

func CPUReset

func CPUReset()

CPUReset performs a hard system reset.

func ConfigureUSBEndpoint

func ConfigureUSBEndpoint(desc descriptor.Descriptor, epSettings []usb.EndpointConfig, setup []usb.SetupConfig)

func DeviceID

func DeviceID() []byte

DeviceID returns an identifier that is unique within a particular chipset.

The identity is one burnt into the MCU itself, or the flash chip at time of manufacture.

It’s possible that two different vendors may allocate the same DeviceID, so callers should take this into account if needing to generate a globally unique id.

The length of the hardware ID is vendor-specific, but 8 bytes (64 bits) and 16 bytes (128 bits) are common.

func EnableCDC

func EnableCDC(txHandler func(), rxHandler func([]byte), setupHandler func(usb.Setup) bool)

func EnterBootloader

func EnterBootloader()

EnterBootloader should perform a system reset in preparation to switch to the bootloader to flash new firmware.

func FlashDataEnd

func FlashDataEnd() uintptr

Return the end of the writable flash area. Usually this is the address one past the end of the on-chip flash.

func FlashDataStart

func FlashDataStart() uintptr

Return the start of the writable flash area, aligned on a page boundary. This is usually just after the program and static data.

func InitADC

func InitADC()

InitADC initializes the ADC.

func InitSerial

func InitSerial()

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

func ReceiveUSBControlPacket

func ReceiveUSBControlPacket() ([cdcLineInfoSize]byte, error)

func SendUSBInPacket

func SendUSBInPacket(ep uint32, data []byte) bool

SendUSBInPacket sends a packet for USB (interrupt in / bulk in).

func SendZlp

func SendZlp()

type ADC

type ADC struct { Pin Pin }

func (ADC) Configure

func (a ADC) Configure(config ADCConfig)

Configure configures a ADC pin to be able to be used to read data.

func (ADC) Get

func (a ADC) Get() uint16

Get returns the current value of a ADC pin, in the range 0..0xffff.

type ADCConfig

type ADCConfig struct { Reference uint32 // analog reference voltage (AREF) in millivolts Resolution uint32 // number of bits for a single conversion (e.g., 8, 10, 12) Samples uint32 // number of samples for a single conversion (e.g., 4, 8, 16, 32) SampleTime uint32 // sample time, in microseconds (µs) }

ADCConfig holds ADC configuration parameters. If left unspecified, the zero value of each parameter will use the peripheral’s default settings.

type BlockDevice

type BlockDevice interface { // ReadAt reads the given number of bytes from the block device. io.ReaderAt // WriteAt writes the given number of bytes to the block device. // // This interface directly writes data to the underlying block device. // Different kinds of devices have different requirements: most can only // write data after the page has been erased, and many can only write data // with specific alignment (such as 4-byte alignment). io.WriterAt // Size returns the number of bytes in this block device. Size() int64 // WriteBlockSize returns the block size in which data can be written to // memory. It can be used by a client to optimize writes, non-aligned writes // should always work correctly. WriteBlockSize() int64 // EraseBlockSize returns the smallest erasable area on this particular chip // in bytes. This is used for the block size in EraseBlocks. // It must be a power of two, and may be as small as 1. A typical size is 4096. EraseBlockSize() int64 // EraseBlocks erases the given number of blocks. An implementation may // transparently coalesce ranges of blocks into larger bundles if the chip // supports this. The start and len parameters are in block numbers, use // EraseBlockSize to map addresses to blocks. EraseBlocks(start, len int64) error }

BlockDevice is the raw device that is meant to store flash data.

type DAC

type DAC struct { }

DAC on the SAMD21.

func (DAC) Configure

func (dac DAC) Configure(config DACConfig)

Configure the DAC. output pin must already be configured.

func (DAC) Set

func (dac DAC) Set(value uint16) error

Set writes a single 16-bit value to the DAC. Since the ATSAMD21 only has a 10-bit DAC, the passed-in value will be scaled down.

type DACConfig

type DACConfig struct { }

DACConfig placeholder for future expansion.

type I2C

type I2C struct { Bus *sam.SERCOM_I2CM_Type SERCOM uint8 }

I2C on the SAMD21.

func (*I2C) Configure

func (i2c *I2C) Configure(config I2CConfig) error

Configure is intended to setup the I2C interface.

func (*I2C) ReadRegister

func (i2c *I2C) ReadRegister(address uint8, register uint8, data []byte) error

ReadRegister transmits the register, restarts the connection as a read operation, and reads the response.

Many I2C-compatible devices are organized in terms of registers. This method is a shortcut to easily read such registers. Also, it only works for devices with 7-bit addresses, which is the vast majority.

func (*I2C) SetBaudRate

func (i2c *I2C) SetBaudRate(br uint32) error

SetBaudRate sets the communication speed for I2C.

func (*I2C) Tx

func (i2c *I2C) Tx(addr uint16, w, r []byte) error

Tx does a single I2C transaction at the specified address. It clocks out the given address, writes the bytes in w, reads back len(r) bytes and stores them in r, and generates a stop condition on the bus.

func (*I2C) WriteByte

func (i2c *I2C) WriteByte(data byte) error

WriteByte writes a single byte to the I2C bus.

func (*I2C) WriteRegister

func (i2c *I2C) WriteRegister(address uint8, register uint8, data []byte) error

WriteRegister transmits first the register and then the data to the peripheral device.

Many I2C-compatible devices are organized in terms of registers. This method is a shortcut to easily write to such registers. Also, it only works for devices with 7-bit addresses, which is the vast majority.

type I2CConfig

type I2CConfig struct { Frequency uint32 SCL Pin SDA Pin }

I2CConfig is used to store config info for I2C.

type I2CMode

type I2CMode int

I2CMode determines if an I2C peripheral is in Controller or Target mode.

type I2CTargetEvent

type I2CTargetEvent uint8

I2CTargetEvent reflects events on the I2C bus

type I2S

type I2S struct { Bus *sam.I2S_Type Frequency uint32 DataFormat I2SDataFormat }

I2S

func (*I2S) Configure

func (i2s *I2S) Configure(config I2SConfig) error

Configure is used to configure the I2S interface. You must call this before you can use the I2S bus.

func (*I2S) Enable

func (i2s *I2S) Enable(enabled bool)

Enabled is used to enable or disable the I2S bus.

func (*I2S) ReadMono

func (i2s *I2S) ReadMono(p []uint16) (n int, err error)

Read mono data from the I2S bus into the provided slice. The I2S bus must already have been configured correctly.

func (*I2S) ReadStereo

func (i2s *I2S) ReadStereo(p []uint32) (n int, err error)

Read stereo data from the I2S bus into the provided slice. The I2S bus must already have been configured correctly.

func (*I2S) SetSampleFrequency

func (i2s *I2S) SetSampleFrequency(freq uint32) error

SetSampleFrequency is used to set the sample frequency for the I2S bus.

func (*I2S) WriteMono

func (i2s *I2S) WriteMono(p []uint16) (n int, err error)

Write mono data to the I2S bus from the provided slice. The I2S bus must already have been configured correctly.

func (*I2S) WriteStereo

func (i2s *I2S) WriteStereo(p []uint32) (n int, err error)

Write stereo data to the I2S bus from the provided slice. The I2S bus must already have been configured correctly.

type I2SClockSource

type I2SClockSource uint8

type I2SConfig

type I2SConfig struct { // clock SCK Pin // word select WS Pin // data out SDO Pin // data in SDI Pin Mode I2SMode Standard I2SStandard ClockSource I2SClockSource DataFormat I2SDataFormat AudioFrequency uint32 MainClockOutput bool Stereo bool }

All fields are optional and may not be required or used on a particular platform.

type I2SDataFormat

type I2SDataFormat uint8

type I2SMode

type I2SMode uint8

type I2SStandard

type I2SStandard uint8

type NullSerial

type NullSerial struct { }

NullSerial is a serial version of /dev/null (or null router): it drops everything that is written to it.

func (NullSerial) Buffered

func (ns NullSerial) Buffered() int

Buffered returns how many bytes are buffered in the UART. It always returns 0 as there are no bytes to read.

func (NullSerial) Configure

func (ns NullSerial) Configure(config UARTConfig) error

Configure does nothing: the null serial has no configuration.

func (NullSerial) ReadByte

func (ns NullSerial) ReadByte() (byte, error)

ReadByte always returns an error because there aren’t any bytes to read.

func (NullSerial) Write

func (ns NullSerial) Write(p []byte) (n int, err error)

Write is a no-op: none of the data is being written and it will not return an error.

func (NullSerial) WriteByte

func (ns NullSerial) WriteByte(b byte) error

WriteByte is a no-op: the null serial doesn’t write bytes.

type PDMConfig

type PDMConfig struct { Stereo bool DIN Pin CLK Pin }

type PWMConfig

type PWMConfig struct { // PWM period in nanosecond. Leaving this zero will pick a reasonable period // value for use with LEDs. // If you want to configure a frequency instead of a period, you can use the // following formula to calculate a period from a frequency: // // period = 1e9 / frequency // Period uint64 }

PWMConfig allows setting some configuration while configuring a PWM peripheral. A zero PWMConfig is ready to use for simple applications such as dimming LEDs.

type Pin

type Pin uint8

Pin is a single pin on a chip, which may be connected to other hardware devices. It can either be used directly as GPIO pin or it can be used in other peripherals like ADC, I2C, etc.

func (Pin) Configure

func (p Pin) Configure(config PinConfig)

Configure this pin with the given configuration.

func (Pin) Get

func (p Pin) Get() bool

Get returns the current value of a GPIO pin when configured as an input or as an output.

func (Pin) High

func (p Pin) High()

High sets this GPIO pin to high, assuming it has been configured as an output pin. It is hardware dependent (and often undefined) what happens if you set a pin to high that is not configured as an output pin.

func (Pin) Low

func (p Pin) Low()

Low sets this GPIO pin to low, assuming it has been configured as an output pin. It is hardware dependent (and often undefined) what happens if you set a pin to low that is not configured as an output pin.

func (Pin) PortMaskClear

func (p Pin) PortMaskClear() (*uint32, uint32)

Return the register and mask to disable a given port. This can be used to implement bit-banged drivers.

func (Pin) PortMaskSet

func (p Pin) PortMaskSet() (*uint32, uint32)

Return the register and mask to enable a given GPIO pin. This can be used to implement bit-banged drivers.

func (Pin) Set

func (p Pin) Set(high bool)

Set the pin to high or low. Warning: only use this on an output pin!

func (Pin) SetInterrupt

func (p Pin) SetInterrupt(change PinChange, callback func(Pin)) error

SetInterrupt sets an interrupt to be executed when a particular pin changes state. The pin should already be configured as an input, including a pull up or down if no external pull is provided.

This call will replace a previously set callback on this pin. You can pass a nil func to unset the pin change interrupt. If you do so, the change parameter is ignored and can be set to any value (such as 0).

type PinChange

type PinChange uint8

type PinConfig

type PinConfig struct { Mode PinMode }

type PinMode

type PinMode uint8

PinMode sets the direction and pull mode of the pin. For example, PinOutput sets the pin as an output and PinInputPullup sets the pin as an input with a pull-up.

type RingBuffer

type RingBuffer struct { rxbuffer [bufferSize]volatile.Register8 head volatile.Register8 tail volatile.Register8 }

RingBuffer is ring buffer implementation inspired by post at https://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php

func (*RingBuffer) Clear

func (rb *RingBuffer) Clear()

Clear resets the head and tail pointer to zero.

func (*RingBuffer) Get

func (rb *RingBuffer) Get() (byte, bool)

Get returns a byte from the buffer. If the buffer is empty, the method will return a false as the second value.

func (*RingBuffer) Put

func (rb *RingBuffer) Put(val byte) bool

Put stores a byte in the buffer. If the buffer is already full, the method will return false.

func (*RingBuffer) Used

func (rb *RingBuffer) Used() uint8

Used returns how many bytes in buffer have been used.

type SPI

type SPI struct { Bus *sam.SERCOM_SPI_Type SERCOM uint8 }

SPI

func (*SPI) Configure

func (spi *SPI) Configure(config SPIConfig) error

Configure is intended to setup the SPI interface.

func (*SPI) Transfer

func (spi *SPI) Transfer(w byte) (byte, error)

Transfer writes/reads a single byte using the SPI interface.

func (*SPI) Tx

func (spi *SPI) Tx(w, r []byte) error

Tx handles read/write operation for SPI interface. Since SPI is a synchronous write/read interface, there must always be the same number of bytes written as bytes read. The Tx method knows about this, and offers a few different ways of calling it.

This form sends the bytes in tx buffer, putting the resulting bytes read into the rx buffer. Note that the tx and rx buffers must be the same size:

spi.Tx(tx, rx)

This form sends the tx buffer, ignoring the result. Useful for sending “commands” that return zeros until all the bytes in the command packet have been received:

spi.Tx(tx, nil)

This form sends zeros, putting the result into the rx buffer. Good for reading a “result packet”:

spi.Tx(nil, rx)

type SPIConfig

type SPIConfig struct { Frequency uint32 SCK Pin SDO Pin SDI Pin LSBFirst bool Mode uint8 }

SPIConfig is used to store config info for SPI.

type Serialer

type Serialer interface { WriteByte(c byte) error Write(data []byte) (n int, err error) Configure(config UARTConfig) error Buffered() int ReadByte() (byte, error) DTR() bool RTS() bool }

type TCC

type TCC sam.TCC_Type

TCC is one timer/counter peripheral, which consists of a counter and multiple output channels (that can be connected to actual pins). You can set the frequency using SetPeriod, but only for all the channels in this TCC peripheral at once.

func (*TCC) Channel

func (tcc *TCC) Channel(pin Pin) (uint8, error)

Channel returns a PWM channel for the given pin. Note that one channel may be shared between multiple pins, and so will have the same duty cycle. If this is not desirable, look for a different TCC peripheral or consider using a different pin.

func (*TCC) Configure

func (tcc *TCC) Configure(config PWMConfig) error

Configure enables and configures this TCC.

func (*TCC) Counter

func (tcc *TCC) Counter() uint32

Counter returns the current counter value of the timer in this TCC peripheral. It may be useful for debugging.

func (*TCC) Set

func (tcc *TCC) Set(channel uint8, value uint32)

Set updates the channel value. This is used to control the channel duty cycle, in other words the fraction of time the channel output is high (or low when inverted). For example, to set it to a 25% duty cycle, use:

tcc.Set(channel, tcc.Top() / 4)

tcc.Set(channel, 0) will set the output to low and tcc.Set(channel, tcc.Top()) will set the output to high, assuming the output isn’t inverted.

func (*TCC) SetInverting

func (tcc *TCC) SetInverting(channel uint8, inverting bool)

SetInverting sets whether to invert the output of this channel. Without inverting, a 25% duty cycle would mean the output is high for 25% of the time and low for the rest. Inverting flips the output as if a NOT gate was placed at the output, meaning that the output would be 25% low and 75% high with a duty cycle of 25%.

func (*TCC) SetPeriod

func (tcc *TCC) SetPeriod(period uint64) error

SetPeriod updates the period of this TCC peripheral. To set a particular frequency, use the following formula:

period = 1e9 / frequency

If you use a period of 0, a period that works well for LEDs will be picked.

SetPeriod will not change the prescaler, but also won’t change the current value in any of the channels. This means that you may need to update the value for the particular channel.

Note that you cannot pick any arbitrary period after the TCC peripheral has been configured. If you want to switch between frequencies, pick the lowest frequency (longest period) once when calling Configure and adjust the frequency here as needed.

func (*TCC) Top

func (tcc *TCC) Top() uint32

Top returns the current counter top, for use in duty cycle calculation. It will only change with a call to Configure or SetPeriod, otherwise it is constant.

The value returned here is hardware dependent. In general, it’s best to treat it as an opaque value that can be divided by some number and passed to Set (see Set documentation for more information).

type UART

type UART struct { Buffer *RingBuffer Bus *sam.SERCOM_USART_Type SERCOM uint8 Interrupt interrupt.Interrupt }

UART on the SAMD21.

func (*UART) Buffered

func (uart *UART) Buffered() int

Buffered returns the number of bytes currently stored in the RX buffer.

func (*UART) Configure

func (uart *UART) Configure(config UARTConfig) error

Configure the UART.

func (*UART) Read

func (uart *UART) Read(data []byte) (n int, err error)

Read from the RX buffer.

func (*UART) ReadByte

func (uart *UART) ReadByte() (byte, error)

ReadByte reads a single byte from the RX buffer. If there is no data in the buffer, returns an error.

func (*UART) Receive

func (uart *UART) Receive(data byte)

Receive handles adding data to the UART’s data buffer. Usually called by the IRQ handler for a machine.

func (*UART) SetBaudRate

func (uart *UART) SetBaudRate(br uint32)

SetBaudRate sets the communication speed for the UART.

func (*UART) Write

func (uart *UART) Write(data []byte) (n int, err error)

Write data over the UART’s Tx. This function blocks until the data is finished being sent.

func (*UART) WriteByte

func (uart *UART) WriteByte(c byte) error

WriteByte writes a byte of data over the UART’s Tx. This function blocks until the data is finished being sent.

type UARTConfig

type UARTConfig struct { BaudRate uint32 TX Pin RX Pin RTS Pin CTS Pin }

UARTConfig is a struct with which a UART (or similar object) can be configured. The baud rate is usually respected, but TX and RX may be ignored depending on the chip and the type of object.

type UARTParity

type UARTParity uint8

UARTParity is the parity setting to be used for UART communication.

type USBDevice

type USBDevice struct { initcomplete bool InitEndpointComplete bool }

func (*USBDevice) Configure

func (dev *USBDevice) Configure(config UARTConfig)

Configure the USB peripheral. The config is here for compatibility with the UART interface.

type WatchdogConfig

type WatchdogConfig struct { // The timeout (in milliseconds) before the watchdog fires. // // If the requested timeout exceeds `MaxTimeout` it will be rounded // down. TimeoutMillis uint32 }

WatchdogConfig holds configuration for the watchdog timer.

Last modified December 15, 2025: content: regenerate machine package docs for 0.40.0 release (9fed2af)