feather-m4

Constants

const RESET_MAGIC_VALUE = 0xf01669ef

used to reset into bootloader

const (
	D0	= PB17	// UART0 RX/PWM available
	D1	= PB16	// UART0 TX/PWM available
	D4	= PA14	// PWM available
	D5	= PA16	// PWM available
	D6	= PA18	// PWM available
	D8	= PB03	// built-in neopixel
	D9	= PA19	// PWM available
	D10	= PA20	// can be used for PWM or UART1 TX
	D11	= PA21	// can be used for PWM or UART1 RX
	D12	= PA22	// PWM available
	D13	= PA23	// PWM available
	D21	= PA13	// PWM available
	D22	= PA12	// PWM available
	D23	= PB22	// PWM available
	D24	= PB23	// PWM available
	D25	= PA17	// PWM available
)

GPIO Pins

const (
	A0	= PA02	// ADC/AIN[0]
	A1	= PA05	// ADC/AIN[2]
	A2	= PB08	// ADC/AIN[3]
	A3	= PB09	// ADC/AIN[4]
	A4	= PA04	// ADC/AIN[5]
	A5	= PA06	// ADC/AIN[10]
)

Analog pins

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

UART0 aka USBCDC pins

const (
	UART_TX_PIN	= D1
	UART_RX_PIN	= D0
)

UART1 pins

const (
	UART2_TX_PIN	= A4
	UART2_RX_PIN	= A5
)

UART2 pins

const (
	SDA_PIN	= D22	// SDA: SERCOM2/PAD[0]
	SCL_PIN	= D21	// SCL: SERCOM2/PAD[1]
)

I2C pins

const (
	SPI0_SCK_PIN	= D25	// SCK: SERCOM1/PAD[1]
	SPI0_MOSI_PIN	= D24	// MOSI: SERCOM1/PAD[3]
	SPI0_MISO_PIN	= D23	// MISO: SERCOM1/PAD[2]
)

SPI 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.

const (
	I2SModeMaster	I2SMode	= iota
	I2SModeSlave
	I2SModePDM
)
const (
	I2StandardPhilips	I2SStandard	= iota
	I2SStandardMSB
	I2SStandardLSB
)
const (
	I2SClockSourceInternal	I2SClockSource	= iota
	I2SClockSourceExternal
)
const (
	I2SDataFormatDefault	I2SDataFormat	= 0
	I2SDataFormat8bit			= 8
	I2SDataFormat16bit			= 16
	I2SDataFormat24bit			= 24
	I2SDataFormat32bit			= 32
)
const NoPin = Pin(-1)

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 CPU_FREQUENCY = 120000000
const (
	PinAnalog		PinMode	= 1
	PinSERCOM		PinMode	= 2
	PinSERCOMAlt		PinMode	= 3
	PinTimer		PinMode	= 4
	PinTimerAlt		PinMode	= 5
	PinTCCPDEC		PinMode	= 6
	PinCom			PinMode	= 7
	PinSDHC			PinMode	= 8
	PinI2S			PinMode	= 9
	PinPCC			PinMode	= 10
	PinGMAC			PinMode	= 11
	PinACCLK		PinMode	= 12
	PinCCL			PinMode	= 13
	PinDigital		PinMode	= 14
	PinInput		PinMode	= 15
	PinInputPullup		PinMode	= 16
	PinOutput		PinMode	= 17
	PinPWME			PinMode	= PinTimer
	PinPWMF			PinMode	= PinTimerAlt
	PinPWMG			PinMode	= PinTCCPDEC
	PinInputPulldown	PinMode	= 18
)
const (
	PA00	Pin	= 0
	PA01	Pin	= 1
	PA02	Pin	= 2
	PA03	Pin	= 3
	PA04	Pin	= 4
	PA05	Pin	= 5
	PA06	Pin	= 6
	PA07	Pin	= 7
	PA08	Pin	= 8
	PA09	Pin	= 9
	PA10	Pin	= 10
	PA11	Pin	= 11
	PA12	Pin	= 12
	PA13	Pin	= 13
	PA14	Pin	= 14
	PA15	Pin	= 15
	PA16	Pin	= 16
	PA17	Pin	= 17
	PA18	Pin	= 18
	PA19	Pin	= 19
	PA20	Pin	= 20
	PA21	Pin	= 21
	PA22	Pin	= 22
	PA23	Pin	= 23
	PA24	Pin	= 24
	PA25	Pin	= 25
	PA26	Pin	= 26
	PA27	Pin	= 27
	PA28	Pin	= 28
	PA29	Pin	= 29
	PA30	Pin	= 30
	PA31	Pin	= 31
	PB00	Pin	= 32
	PB01	Pin	= 33
	PB02	Pin	= 34
	PB03	Pin	= 35
	PB04	Pin	= 36
	PB05	Pin	= 37
	PB06	Pin	= 38
	PB07	Pin	= 39
	PB08	Pin	= 40
	PB09	Pin	= 41
	PB10	Pin	= 42
	PB11	Pin	= 43
	PB12	Pin	= 44
	PB13	Pin	= 45
	PB14	Pin	= 46
	PB15	Pin	= 47
	PB16	Pin	= 48
	PB17	Pin	= 49
	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
	PB31	Pin	= 63
)

Hardware pins

const (
	// SERCOM_FREQ_REF is always reference frequency on SAMD51 regardless of CPU speed.
	SERCOM_FREQ_REF	= 48000000

	// Default rise time in nanoseconds, based on 4.7K ohm pull up resistors
	riseTimeNanoseconds	= 125

	// wire bus states
	wireUnknownState	= 0
	wireIdleState		= 1
	wireOwnerState		= 2
	wireBusyState		= 3

	// wire commands
	wireCmdNoAction		= 0
	wireCmdRepeatStart	= 1
	wireCmdRead		= 2
	wireCmdStop		= 3
)

Variables

var (
	I2C0 = I2C{Bus: sam.SERCOM2_I2CM,
		SDA:		SDA_PIN,
		SCL:		SCL_PIN,
		PinMode:	PinSERCOM}
)

I2C on the Feather M4.

var (
	SPI0 = SPI{Bus: sam.SERCOM1_SPIM,
		SCK:		SPI0_SCK_PIN,
		MOSI:		SPI0_MOSI_PIN,
		MISO:		SPI0_MISO_PIN,
		DOpad:		spiTXPad3SCK1,
		DIpad:		sercomRXPad2,
		MISOPinMode:	PinSERCOM,
		MOSIPinMode:	PinSERCOM,
		SCKPinMode:	PinSERCOM,
	}
)

SPI on the Feather M4.

var (
	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")
)
var (
	// UART0 is actually a USB CDC interface.
	UART0	= USBCDC{Buffer: NewRingBuffer()}

	// The first hardware serial port on the SAMD51. Uses the SERCOM3 interface.
	UART1	= UART{Bus: sam.SERCOM3_USART_INT,
		Buffer:	NewRingBuffer(),
		Mode:	PinSERCOMAlt,
	}

	// The second hardware serial port on the SAMD51. Uses the SERCOM0 interface.
	UART2	= UART{
		Buffer:	NewRingBuffer(),
		Bus:	sam.SERCOM0_USART_INT,
		Mode:	PinSERCOMAlt,
	}
)
var (
	ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
)

func InitADC

func InitADC()

InitADC initializes the ADC.

func InitPWM

func InitPWM()

InitPWM initializes the PWM interface.

func NewACMFunctionalDescriptor

func NewACMFunctionalDescriptor(subtype, d0 uint8) ACMFunctionalDescriptor

NewACMFunctionalDescriptor returns a new USB ACMFunctionalDescriptor.

func NewCDCCSInterfaceDescriptor

func NewCDCCSInterfaceDescriptor(subtype, d0, d1 uint8) CDCCSInterfaceDescriptor

NewCDCCSInterfaceDescriptor returns a new USB CDCCSInterfaceDescriptor.

func NewCDCDescriptor

func NewCDCDescriptor(i IADDescriptor, c InterfaceDescriptor,
	h CDCCSInterfaceDescriptor,
	cm ACMFunctionalDescriptor,
	fd CDCCSInterfaceDescriptor,
	callm CMFunctionalDescriptor,
	ci EndpointDescriptor,
	di InterfaceDescriptor,
	outp EndpointDescriptor,
	inp EndpointDescriptor) CDCDescriptor

func NewCMFunctionalDescriptor

func NewCMFunctionalDescriptor(subtype, d0, d1 uint8) CMFunctionalDescriptor

NewCMFunctionalDescriptor returns a new USB CMFunctionalDescriptor.

func NewConfigDescriptor

func NewConfigDescriptor(totalLength uint16, interfaces uint8) ConfigDescriptor

NewConfigDescriptor returns a new USB ConfigDescriptor.

func NewDeviceDescriptor

func NewDeviceDescriptor(class, subClass, proto, packetSize0 uint8, vid, pid, version uint16, im, ip, is, configs uint8) DeviceDescriptor

NewDeviceDescriptor returns a USB DeviceDescriptor.

func NewEndpointDescriptor

func NewEndpointDescriptor(addr, attr uint8, packetSize uint16, interval uint8) EndpointDescriptor

NewEndpointDescriptor returns a new USB EndpointDescriptor.

func NewIADDescriptor

func NewIADDescriptor(firstInterface, count, class, subClass, protocol uint8) IADDescriptor

NewIADDescriptor returns a new USB IADDescriptor.

func NewInterfaceDescriptor

func NewInterfaceDescriptor(n, numEndpoints, class, subClass, protocol uint8) InterfaceDescriptor

NewInterfaceDescriptor returns a new USB InterfaceDescriptor.

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

func ResetProcessor

func ResetProcessor()

ResetProcessor should perform a system reset in preperation to switch to the bootloader to flash new firmware.

type ACMFunctionalDescriptor

type ACMFunctionalDescriptor struct {
	len		uint8
	dtype		uint8	// 0x24
	subtype		uint8	// 1
	bmCapabilities	uint8
}

ACMFunctionalDescriptor is a Abstract Control Model (ACM) USB descriptor.

func (ACMFunctionalDescriptor) Bytes

func (d ACMFunctionalDescriptor) Bytes() []byte

Bytes returns the ACMFunctionalDescriptor data.

type ADC

type ADC struct {
	Pin Pin
}

func (ADC) Configure

func (a ADC) Configure()

Configure configures a ADCPin 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 CDCCSInterfaceDescriptor

type CDCCSInterfaceDescriptor struct {
	len	uint8	// 5
	dtype	uint8	// 0x24
	subtype	uint8
	d0	uint8
	d1	uint8
}

CDCCSInterfaceDescriptor is a CDC CS interface descriptor.

func (CDCCSInterfaceDescriptor) Bytes

func (d CDCCSInterfaceDescriptor) Bytes() []byte

Bytes returns CDCCSInterfaceDescriptor data.

type CDCDescriptor

type CDCDescriptor struct {
	//	IAD
	iad	IADDescriptor	// Only needed on compound device

	//	Control
	cif	InterfaceDescriptor
	header	CDCCSInterfaceDescriptor

	// CDC control
	controlManagement	ACMFunctionalDescriptor		// ACM
	functionalDescriptor	CDCCSInterfaceDescriptor	// CDC_UNION
	callManagement		CMFunctionalDescriptor		// Call Management
	cifin			EndpointDescriptor

	//	CDC Data
	dif	InterfaceDescriptor
	in	EndpointDescriptor
	out	EndpointDescriptor
}

CDCDescriptor is the Communication Device Class (CDC) descriptor.

func (CDCDescriptor) Bytes

func (d CDCDescriptor) Bytes() []byte

Bytes returns CDCDescriptor data.

type CMFunctionalDescriptor

type CMFunctionalDescriptor struct {
	bFunctionLength		uint8
	bDescriptorType		uint8	// 0x24
	bDescriptorSubtype	uint8	// 1
	bmCapabilities		uint8
	bDataInterface		uint8
}

CMFunctionalDescriptor is the functional descriptor general format.

func (CMFunctionalDescriptor) Bytes

func (d CMFunctionalDescriptor) Bytes() []byte

Bytes returns the CMFunctionalDescriptor data.

type ConfigDescriptor

type ConfigDescriptor struct {
	bLength			uint8	// 9
	bDescriptorType		uint8	// 2
	wTotalLength		uint16	// total length
	bNumInterfaces		uint8
	bConfigurationValue	uint8
	iConfiguration		uint8
	bmAttributes		uint8
	bMaxPower		uint8
}

ConfigDescriptor implements the standard USB configuration descriptor.

Table 9-10. Standard Configuration Descriptor bLength, bDescriptorType, wTotalLength, bNumInterfaces, bConfigurationValue, iConfiguration bmAttributes, bMaxPower

func (ConfigDescriptor) Bytes

func (d ConfigDescriptor) Bytes() []byte

Bytes returns ConfigDescriptor data.

type DeviceDescriptor

type DeviceDescriptor struct {
	bLength			uint8	// 18
	bDescriptorType		uint8	// 1 USB_DEVICE_DESCRIPTOR_TYPE
	bcdUSB			uint16	// 0x200
	bDeviceClass		uint8
	bDeviceSubClass		uint8
	bDeviceProtocol		uint8
	bMaxPacketSize0		uint8	// Packet 0
	idVendor		uint16
	idProduct		uint16
	bcdDevice		uint16	// 0x100
	iManufacturer		uint8
	iProduct		uint8
	iSerialNumber		uint8
	bNumConfigurations	uint8
}

DeviceDescriptor implements the USB standard device descriptor.

Table 9-8. Standard Device Descriptor bLength, bDescriptorType, bcdUSB, bDeviceClass, bDeviceSubClass, bDeviceProtocol, bMaxPacketSize0, idVendor, idProduct, bcdDevice, iManufacturer, iProduct, iSerialNumber, bNumConfigurations */

func (DeviceDescriptor) Bytes

func (d DeviceDescriptor) Bytes() []byte

Bytes returns DeviceDescriptor data

type EndpointDescriptor

type EndpointDescriptor struct {
	bLength			uint8	// 7
	bDescriptorType		uint8	// 5
	bEndpointAddress	uint8
	bmAttributes		uint8
	wMaxPacketSize		uint16
	bInterval		uint8
}

EndpointDescriptor implements the standard USB endpoint descriptor.

Table 9-13. Standard Endpoint Descriptor bLength, bDescriptorType, bEndpointAddress, bmAttributes, wMaxPacketSize, bInterval

func (EndpointDescriptor) Bytes

func (d EndpointDescriptor) Bytes() []byte

Bytes returns EndpointDescriptor data.

type I2C

type I2C struct {
	Bus	*sam.SERCOM_I2CM_Type
	SCL	Pin
	SDA	Pin
	PinMode	PinMode
}

I2C on the SAMD51.

func (I2C) Configure

func (i2c I2C) Configure(config I2CConfig)

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)

SetBaudRate sets the communication speed for the 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® 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 I2SClockSource

type I2SClockSource uint8

type I2SConfig

type I2SConfig struct {
	SCK			Pin
	WS			Pin
	SD			Pin
	Mode			I2SMode
	Standard		I2SStandard
	ClockSource		I2SClockSource
	DataFormat		I2SDataFormat
	AudioFrequency		uint32
	MasterClockOutput	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 IADDescriptor

type IADDescriptor struct {
	bLength			uint8	// 8
	bDescriptorType		uint8	// 11
	bFirstInterface		uint8
	bInterfaceCount		uint8
	bFunctionClass		uint8
	bFunctionSubClass	uint8
	bFunctionProtocol	uint8
	iFunction		uint8
}

IADDescriptor is an Interface Association Descriptor, which is used to bind 2 interfaces together in CDC composite device.

Standard Interface Association Descriptor: bLength, bDescriptorType, bFirstInterface, bInterfaceCount, bFunctionClass, bFunctionSubClass, bFunctionProtocol, iFunction

func (IADDescriptor) Bytes

func (d IADDescriptor) Bytes() []byte

Bytes returns IADDescriptor data.

type InterfaceDescriptor

type InterfaceDescriptor struct {
	bLength			uint8	// 9
	bDescriptorType		uint8	// 4
	bInterfaceNumber	uint8
	bAlternateSetting	uint8
	bNumEndpoints		uint8
	bInterfaceClass		uint8
	bInterfaceSubClass	uint8
	bInterfaceProtocol	uint8
	iInterface		uint8
}

InterfaceDescriptor implements the standard USB interface descriptor.

Table 9-12. Standard Interface Descriptor bLength, bDescriptorType, bInterfaceNumber, bAlternateSetting, bNumEndpoints, bInterfaceClass, bInterfaceSubClass, bInterfaceProtocol, iInterface

func (InterfaceDescriptor) Bytes

func (d InterfaceDescriptor) Bytes() []byte

Bytes returns InterfaceDescriptor data.

type MSCDescriptor

type MSCDescriptor struct {
	msc	InterfaceDescriptor
	in	EndpointDescriptor
	out	EndpointDescriptor
}

MSCDescriptor is not used yet.

type PWM

type PWM struct {
	Pin Pin
}

func (PWM) Configure

func (pwm PWM) Configure()

Configure configures a PWM pin for output.

func (PWM) Set

func (pwm PWM) Set(value uint16)

Set turns on the duty cycle for a PWM pin using the provided value.

type Pin

type Pin int8

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.

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) Toggle

func (p Pin) Toggle()

Toggle switches an output pin from low to high or from high to low. Warning: only use this on an output pin!

type PinConfig

type PinConfig struct {
	Mode PinMode
}

type PinMode

type PinMode uint8

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

It has some limitations currently due to how “volatile” variables that are members of a struct are not compiled correctly by TinyGo. See https://github.com/tinygo-org/tinygo/issues/151 for details.

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_SPIM_Type
	SCK		Pin
	MOSI		Pin
	MISO		Pin
	DOpad		int
	DIpad		int
	SCKPinMode	PinMode
	MOSIPinMode	PinMode
	MISOPinMode	PinMode
}

SPI

func (SPI) Configure

func (spi SPI) Configure(config SPIConfig)

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 syncronous 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
	MOSI		Pin
	MISO		Pin
	LSBFirst	bool
	Mode		uint8
}

SPIConfig is used to store config info for SPI.

type UART

type UART struct {
	Buffer	*RingBuffer
	Bus	*sam.SERCOM_USART_INT_Type
	Mode	PinMode
}

UART on the SAMD51.

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)

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 to the UART.

func (UART) WriteByte

func (uart UART) WriteByte(c byte) error

WriteByte writes a byte of data to the UART.

type UARTConfig

type UARTConfig struct {
	BaudRate	uint32
	TX		Pin
	RX		Pin
}

type USBCDC

type USBCDC struct {
	Buffer *RingBuffer
}

USBCDC is the USB CDC aka serial over USB interface on the SAMD21.

func (USBCDC) Buffered

func (usbcdc USBCDC) Buffered() int

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

func (USBCDC) Configure

func (usbcdc USBCDC) Configure(config UARTConfig)

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

func (USBCDC) DTR

func (usbcdc USBCDC) DTR() bool

func (USBCDC) RTS

func (usbcdc USBCDC) RTS() bool

func (USBCDC) Read

func (usbcdc USBCDC) Read(data []byte) (n int, err error)

Read from the RX buffer.

func (USBCDC) ReadByte

func (usbcdc USBCDC) ReadByte() (byte, error)

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

func (USBCDC) Receive

func (usbcdc USBCDC) Receive(data byte)

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

func (USBCDC) Write

func (usbcdc USBCDC) Write(data []byte) (n int, err error)

Write data to the USBCDC.

func (USBCDC) WriteByte

func (usbcdc USBCDC) WriteByte(c byte) error

WriteByte writes a byte of data to the USB CDC interface.