nrf52840-mdk

Constants

const HasLowFrequencyCrystal = true

const (
    LED        Pin    = LED_GREEN
    LED_GREEN    Pin    = 22
    LED_RED        Pin    = 23
    LED_BLUE    Pin    = 24
)

LEDs on the nrf52840-mdk (nRF52840 dev board)

const (
    UART_TX_PIN    Pin    = 20
    UART_RX_PIN    Pin    = 19
)

UART pins

const (
    SDA_PIN    = NoPin
    SCL_PIN    = NoPin
)

I2C pins (unused)

const (
    SPI0_SCK_PIN    = NoPin
    SPI0_MOSI_PIN    = NoPin
    SPI0_MISO_PIN    = NoPin
)

SPI pins (unused)

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 oneof 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 (
    P0_00    Pin    = 0
    P0_01    Pin    = 1
    P0_02    Pin    = 2
    P0_03    Pin    = 3
    P0_04    Pin    = 4
    P0_05    Pin    = 5
    P0_06    Pin    = 6
    P0_07    Pin    = 7
    P0_08    Pin    = 8
    P0_09    Pin    = 9
    P0_10    Pin    = 10
    P0_11    Pin    = 11
    P0_12    Pin    = 12
    P0_13    Pin    = 13
    P0_14    Pin    = 14
    P0_15    Pin    = 15
    P0_16    Pin    = 16
    P0_17    Pin    = 17
    P0_18    Pin    = 18
    P0_19    Pin    = 19
    P0_20    Pin    = 20
    P0_21    Pin    = 21
    P0_22    Pin    = 22
    P0_23    Pin    = 23
    P0_24    Pin    = 24
    P0_25    Pin    = 25
    P0_26    Pin    = 26
    P0_27    Pin    = 27
    P0_28    Pin    = 28
    P0_29    Pin    = 29
    P0_30    Pin    = 30
    P0_31    Pin    = 31
    P1_00    Pin    = 32
    P1_01    Pin    = 33
    P1_02    Pin    = 34
    P1_03    Pin    = 35
    P1_04    Pin    = 36
    P1_05    Pin    = 37
    P1_06    Pin    = 38
    P1_07    Pin    = 39
    P1_08    Pin    = 40
    P1_09    Pin    = 41
    P1_10    Pin    = 42
    P1_11    Pin    = 43
    P1_12    Pin    = 44
    P1_13    Pin    = 45
    P1_14    Pin    = 46
    P1_15    Pin    = 47
)

Hardware pins

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 CPUFrequency

func CPUFrequency() uint32

func InitADC

func InitADC()

InitADC initializes the registers needed for ADC.

func InitPWM

func InitPWM()

InitPWM initializes the registers needed for PWM.

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

type ADC

type ADC struct {
    Pin Pin
}

func (ADC) Configure

func (a ADC) Configure()

Configure configures an ADC pin to be able to read analog data.

func (ADC) Get

func (a ADC) Get() uint16

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

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 readoperation, and reads the response.

Many I2C-compatible devices are organized in terms of registers. This methodis a shortcut to easily read such registers. Also, it only works for deviceswith 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 theperipheral device.

Many I2C-compatible devices are organized in terms of registers. This methodis a shortcut to easily write to such registers. Also, it only works fordevices 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
}

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 hardwaredevices. It can either be used directly as GPIO pin or it can be used inother 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 outputpin. It is hardware dependent (and often undefined) what happens if you set apin 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 outputpin. It is hardware dependent (and often undefined) what happens if you set apin 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 toimplement 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 toimplement 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 athttps://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php

It has some limitations currently due to how “volatile” variables that aremembers 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 alreadyfull, 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/readinterface, 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 zerosuntil 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
}