microbit

Constants

const HasLowFrequencyCrystal = false

The micro:bit does not have a 32kHz crystal on board.

const (
	BUTTON	Pin	= BUTTONA
	BUTTONA	Pin	= 17
	BUTTONB	Pin	= 26
)

Buttons on the micro:bit (A and B)

const (
	UART_TX_PIN	Pin	= 24
	UART_RX_PIN	Pin	= 25
)

UART pins

const (
	ADC0	Pin	= 3	// P0 on the board
	ADC1	Pin	= 2	// P1 on the board
	ADC2	Pin	= 1	// P2 on the board
)

ADC pins

const (
	SDA_PIN	Pin	= 30	// P20 on the board
	SCL_PIN	Pin	= 0	// P19 on the board
)

I2C pins

const (
	SPI0_SCK_PIN	Pin	= 23	// P13 on the board
	SPI0_MOSI_PIN	Pin	= 21	// P15 on the board
	SPI0_MISO_PIN	Pin	= 22	// P14 on the board
)

SPI pins

const (
	P0	Pin	= 3
	P1	Pin	= 2
	P2	Pin	= 1
	P3	Pin	= 4
	P4	Pin	= 5
	P5	Pin	= 17
	P6	Pin	= 12
	P7	Pin	= 11
	P8	Pin	= 18
	P9	Pin	= 10
	P10	Pin	= 6
	P11	Pin	= 26
	P12	Pin	= 20
	P13	Pin	= 23
	P14	Pin	= 22
	P15	Pin	= 21
	P16	Pin	= 16
)

GPIO/Analog pins

const (
	LED_COL_1	Pin	= 4
	LED_COL_2	Pin	= 5
	LED_COL_3	Pin	= 6
	LED_COL_4	Pin	= 7
	LED_COL_5	Pin	= 8
	LED_COL_6	Pin	= 9
	LED_COL_7	Pin	= 10
	LED_COL_8	Pin	= 11
	LED_COL_9	Pin	= 12
	LED_ROW_1	Pin	= 13
	LED_ROW_2	Pin	= 14
	LED_ROW_3	Pin	= 15
)

LED matrix 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 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 (
	PinInput		PinMode	= (nrf.GPIO_PIN_CNF_DIR_Input << nrf.GPIO_PIN_CNF_DIR_Pos) | (nrf.GPIO_PIN_CNF_INPUT_Connect << nrf.GPIO_PIN_CNF_INPUT_Pos)
	PinInputPullup		PinMode	= PinInput | (nrf.GPIO_PIN_CNF_PULL_Pullup << nrf.GPIO_PIN_CNF_PULL_Pos)
	PinInputPulldown	PinMode	= PinOutput | (nrf.GPIO_PIN_CNF_PULL_Pulldown << nrf.GPIO_PIN_CNF_PULL_Pos)
	PinOutput		PinMode	= (nrf.GPIO_PIN_CNF_DIR_Output << nrf.GPIO_PIN_CNF_DIR_Pos) | (nrf.GPIO_PIN_CNF_INPUT_Disconnect << nrf.GPIO_PIN_CNF_INPUT_Pos)
)
const CPU_FREQUENCY = 16000000

Variables

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 (
	ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
)
var (
	// UART0 is the hardware serial port on the NRF.
	UART0 = UART{Buffer: NewRingBuffer()}
)

UART

var (
	I2C0	= I2C{Bus: nrf.TWI0}
	I2C1	= I2C{Bus: nrf.TWI1}
)

There are 2 I2C interfaces on the NRF.

var (
	SPI0	= SPI{Bus: nrf.SPI0}
	SPI1	= SPI{Bus: nrf.SPI1}
)

There are 2 SPI interfaces on the NRF5x.

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

type ADC

type ADC struct {
	Pin Pin
}

type I2C

type I2C struct {
	Bus *nrf.TWI_Type
}

I2C on the NRF.

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) 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) 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 PWM

type PWM struct {
	Pin Pin
}

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!

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 *nrf.SPI_Type
}

SPI on the NRF.

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
}

UART on the NRF.

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
}