microbit
Constants
const HasLowFrequencyCrystal = false
The micro:bit does not have a 32kHz crystal on board.
const (
P0 = P0_03
P1 = P0_02
P2 = P0_01
P3 = P0_04
P4 = P0_05
P5 = P0_17
P6 = P0_12
P7 = P0_11
P8 = P0_18
P9 = P0_10
P10 = P0_06
P11 = P0_26
P12 = P0_20
P13 = P0_23
P14 = P0_22
P15 = P0_21
P16 = P0_16
)
GPIO/Analog pins
const (
BUTTONA = P0_17
BUTTONB = P0_26
BUTTON = BUTTONA
)
Buttons on the micro:bit (A and B)
const (
UART_TX_PIN = P0_24
UART_RX_PIN = P0_25
)
UART pins
const (
ADC0 = P0_03 // P0 on the board
ADC1 = P0_02 // P1 on the board
ADC2 = P0_01 // P2 on the board
)
ADC pins
const (
SDA_PIN = P0_30 // P20 on the board
SCL_PIN = P0_00 // P19 on the board
)
I2C pins
const (
SPI0_SCK_PIN = P0_23 // P13 on the board
SPI0_SDO_PIN = P0_21 // P15 on the board
SPI0_SDI_PIN = P0_22 // P14 on the board
)
SPI pins
const (
LED_COL_1 = P0_04
LED_COL_2 = P0_05
LED_COL_3 = P0_06
LED_COL_4 = P0_07
LED_COL_5 = P0_08
LED_COL_6 = P0_09
LED_COL_7 = P0_10
LED_COL_8 = P0_11
LED_COL_9 = P0_12
LED_ROW_1 = P0_13
LED_ROW_2 = P0_14
LED_ROW_3 = P0_15
)
LED matrix pins
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
)
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 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 (
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 = PinInput | (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_Connect << nrf.GPIO_PIN_CNF_INPUT_Pos)
)
const (
PinRising PinChange = nrf.GPIOTE_CONFIG_POLARITY_LoToHi
PinFalling PinChange = nrf.GPIOTE_CONFIG_POLARITY_HiToLo
PinToggle PinChange = nrf.GPIOTE_CONFIG_POLARITY_Toggle
)
Pin change interrupt constants for SetInterrupt.
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 DefaultUART = UART0
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 (
// UART0 is the hardware UART on the NRF SoC.
_UART0 = UART{Buffer: NewRingBuffer()}
UART0 = &_UART0
)
UART
var Flash flashBlockDevice
var (
SPI0 = SPI{Bus: nrf.SPI0}
SPI1 = SPI{Bus: nrf.SPI1}
)
There are 2 SPI interfaces on the NRF51.
var (
I2C0 = &I2C{Bus: nrf.TWI0}
I2C1 = &I2C{Bus: nrf.TWI1}
)
There are 2 I2C interfaces on the NRF.
var (
ErrPWMPeriodTooLong = errors.New("pwm: period too long")
)
var Serial = DefaultUART
Serial is implemented via the default (usually the first) UART on the chip.
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")
)
func CPUFrequency
func CPUFrequency() uint32
func CPUReset
func CPUReset()
CPUReset performs a hard system reset.
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) is common.
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 GetRNG
func GetRNG() (ret uint32, err error)
GetRNG returns 32 bits of non-deterministic random data based on internal thermal noise. According to Nordic’s documentation, the random output is suitable for cryptographic purposes.
func InitADC
func InitADC()
InitADC initializes the registers needed for ADC.
func InitSerial
func InitSerial()
func NewRingBuffer
func NewRingBuffer() *RingBuffer
NewRingBuffer returns a new ring buffer.
func ReadTemperature
func ReadTemperature() int32
ReadTemperature reads the silicon die temperature of the chip. The return value is in milli-celsius.
type ADC
type ADC struct {
Pin Pin
}
func (ADC) Configure
func (a ADC) Configure(ADCConfig)
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 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.
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 I2C
type I2C struct {
Bus *nrf.TWI_Type
mode I2CMode
}
I2C on the NRF51 and NRF52.
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 I2C frequency. It has the side effect of also enabling the I2C hardware if disabled beforehand.
func (*I2C) Tx
func (i2c *I2C) Tx(addr uint16, w, r []byte) (err 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) 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
Mode I2CMode
}
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 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 the pin is 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 *nrf.SPI_Type
}
SPI on the NRF.
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 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 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.