const (
	LED	Pin	= GPIO25



	ENABLE_3V3	Pin	= GPIO10
const (

	I2C1_SDA_PIN	Pin	= NoPin
	I2C1_SCL_PIN	Pin	= NoPin

I2C pins

const (

	SPI1_SCK_PIN	Pin	= NoPin
	SPI1_SDO_PIN	Pin	= NoPin
	SPI1_SDI_PIN	Pin	= NoPin

SPI pins.

const (

UART 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.

	// 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'.
const (
	// I2CModeController represents an I2C peripheral in controller mode.
	I2CModeController	I2CMode	= iota

	// I2CModeTarget represents an I2C peripheral in target mode.
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 (
	PinOutput	PinMode	= iota
const (
	// Edge falling
	PinFalling	PinChange	= 4 << iota
	// Edge rising

	PinToggle	= PinFalling | PinRising

Pin change interrupt constants for SetInterrupt.

const (
	// GPIO pins
	GPIO0	Pin	= 0	// peripherals: PWM0 channel A
	GPIO1	Pin	= 1	// peripherals: PWM0 channel B
	GPIO2	Pin	= 2	// peripherals: PWM1 channel A
	GPIO3	Pin	= 3	// peripherals: PWM1 channel B
	GPIO4	Pin	= 4	// peripherals: PWM2 channel A
	GPIO5	Pin	= 5	// peripherals: PWM2 channel B
	GPIO6	Pin	= 6	// peripherals: PWM3 channel A
	GPIO7	Pin	= 7	// peripherals: PWM3 channel B
	GPIO8	Pin	= 8	// peripherals: PWM4 channel A
	GPIO9	Pin	= 9	// peripherals: PWM4 channel B
	GPIO10	Pin	= 10	// peripherals: PWM5 channel A
	GPIO11	Pin	= 11	// peripherals: PWM5 channel B
	GPIO12	Pin	= 12	// peripherals: PWM6 channel A
	GPIO13	Pin	= 13	// peripherals: PWM6 channel B
	GPIO14	Pin	= 14	// peripherals: PWM7 channel A
	GPIO15	Pin	= 15	// peripherals: PWM7 channel B
	GPIO16	Pin	= 16	// peripherals: PWM0 channel A
	GPIO17	Pin	= 17	// peripherals: PWM0 channel B
	GPIO18	Pin	= 18	// peripherals: PWM1 channel A
	GPIO19	Pin	= 19	// peripherals: PWM1 channel B
	GPIO20	Pin	= 20	// peripherals: PWM2 channel A
	GPIO21	Pin	= 21	// peripherals: PWM2 channel B
	GPIO22	Pin	= 22	// peripherals: PWM3 channel A
	GPIO23	Pin	= 23	// peripherals: PWM3 channel B
	GPIO24	Pin	= 24	// peripherals: PWM4 channel A
	GPIO25	Pin	= 25	// peripherals: PWM4 channel B
	GPIO26	Pin	= 26	// peripherals: PWM5 channel A
	GPIO27	Pin	= 27	// peripherals: PWM5 channel B
	GPIO28	Pin	= 28	// peripherals: PWM6 channel A
	GPIO29	Pin	= 29	// peripherals: PWM6 channel B

	// Analog pins
	ADC0	Pin	= GPIO26
	ADC1	Pin	= GPIO27
	ADC2	Pin	= GPIO28
	ADC3	Pin	= GPIO29
const RESETS_RESET_Msk = 0x01ffffff

RESETS_RESET_Msk is bitmask to reset all peripherals

TODO: This field is not available in the device file.

const (
	// DPRAM : Endpoint control register
	usbEpControlEnable			= 0x80000000
	usbEpControlDoubleBuffered		= 0x40000000
	usbEpControlInterruptPerBuff		= 0x20000000
	usbEpControlInterruptPerDoubleBuff	= 0x10000000
	usbEpControlEndpointType		= 0x0c000000
	usbEpControlInterruptOnStall		= 0x00020000
	usbEpControlInterruptOnNak		= 0x00010000
	usbEpControlBufferAddress		= 0x0000ffff

	usbEpControlEndpointTypeControl		= 0x00000000
	usbEpControlEndpointTypeISO		= 0x04000000
	usbEpControlEndpointTypeBulk		= 0x08000000
	usbEpControlEndpointTypeInterrupt	= 0x0c000000

	// Endpoint buffer control bits
	usbBuf1CtrlFull		= 0x80000000
	usbBuf1CtrlLast		= 0x40000000
	usbBuf1CtrlData0Pid	= 0x20000000
	usbBuf1CtrlData1Pid	= 0x00000000
	usbBuf1CtrlSel		= 0x10000000
	usbBuf1CtrlStall	= 0x08000000
	usbBuf1CtrlAvail	= 0x04000000
	usbBuf1CtrlLenMask	= 0x03FF0000
	usbBuf0CtrlFull		= 0x00008000
	usbBuf0CtrlLast		= 0x00004000
	usbBuf0CtrlData0Pid	= 0x00000000
	usbBuf0CtrlData1Pid	= 0x00002000
	usbBuf0CtrlSel		= 0x00001000
	usbBuf0CtrlStall	= 0x00000800
	usbBuf0CtrlAvail	= 0x00000400
	usbBuf0CtrlLenMask	= 0x000003FF

	USBBufferLen	= 64
const (
	LS_SE0	= 0b00
	LS_J	= 0b01
	LS_K	= 0b10
	LS_SE1	= 0b11
const (
	// WatchdogMaxTimeout in milliseconds (approx 8.3s).
	// Nominal 1us per watchdog tick, 24-bit counter,
	// but due to errata two ticks consumed per 1us.
	// See: Errata RP2040-E1
	WatchdogMaxTimeout = (rp.WATCHDOG_LOAD_LOAD_Msk / 1000) / 2

On some boards, the XOSC can take longer than usual to stabilize. On such boards, this is needed to avoid a hard fault on boot/reset. Refer to PICO_XOSC_STARTUP_DELAY_MULTIPLIER in the Pico SDK for additional details.

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.

	// ParityOdd means to expect that the total number of 1 bits sent
	// should be an odd number.


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 Flash flashBlockDevice
var (
	UART0	= &_UART0
		Buffer:	NewRingBuffer(),
		Bus:	rp.UART0,

	UART1	= &_UART1
		Buffer:	NewRingBuffer(),
		Bus:	rp.UART1,

UART on the RP2040

var (
	I2C0	= &_I2C0
	_I2C0	= I2C{
		Bus: rp.I2C0,
	I2C1	= &_I2C1
	_I2C1	= I2C{
		Bus: rp.I2C1,

I2C on the RP2040.

var (
	ErrInvalidI2CBaudrate	= errors.New("invalid i2c baudrate")
	ErrInvalidTgtAddr	= errors.New("invalid target i2c address not in 0..0x80 or is reserved")
	ErrI2CGeneric		= errors.New("i2c error")
	ErrRP2040I2CDisable	= errors.New("i2c rp2040 peripheral timeout in disable")
	errInvalidI2CSDA	= errors.New("invalid I2C SDA pin")
	errInvalidI2CSCL	= errors.New("invalid I2C SCL pin")
	ErrI2CAlreadyListening	= errors.New("i2c already listening")
	ErrI2CWrongMode		= errors.New("i2c wrong mode")
	ErrI2CUnderflow		= errors.New("i2c underflow")
var (
	ErrBadPeriod = errors.New("period outside valid range 8ns..268ms")
var (
	PWM0	= getPWMGroup(0)
	PWM1	= getPWMGroup(1)
	PWM2	= getPWMGroup(2)
	PWM3	= getPWMGroup(3)
	PWM4	= getPWMGroup(4)
	PWM5	= getPWMGroup(5)
	PWM6	= getPWMGroup(6)
	PWM7	= getPWMGroup(7)

Hardware Pulse Width Modulation (PWM) API PWM peripherals available on RP2040. Each peripheral has 2 pins available for a total of 16 available PWM outputs. Some pins may not be available on some boards.

The RP2040 PWM block has 8 identical slices. Each slice can drive two PWM output signals, or measure the frequency or duty cycle of an input signal. This gives a total of up to 16 controllable PWM outputs. All 30 GPIOs can be driven by the PWM block

The PWM hardware functions by continuously comparing the input value to a free-running counter. This produces a toggling output where the amount of time spent at the high output level is proportional to the input value. The fraction of time spent at the high signal level is known as the duty cycle of the signal.

The default behaviour of a PWM slice is to count upward until the wrap value (\ref pwm_config_set_wrap) is reached, and then immediately wrap to 0. PWM slices also offer a phase-correct mode, where the counter starts to count downward after reaching TOP, until it reaches 0 again.

var RTC = (*rtcType)(unsafe.Pointer(rp.RTC))
var (
	ErrRtcDelayTooSmall	= errors.New("RTC interrupt deplay is too small, shall be at least 1 second")
	ErrRtcDelayTooLarge	= errors.New("RTC interrupt deplay is too large, shall be no more than 1 day")
var (
	SPI0	= &_SPI0
	_SPI0	= SPI{
		Bus: rp.SPI0,
	SPI1	= &_SPI1
	_SPI1	= SPI{
		Bus: rp.SPI1,

SPI on the RP2040

var (
	ErrLSBNotSupported	= errors.New("SPI LSB unsupported on PL022")
	ErrSPITimeout		= errors.New("SPI timeout")
	ErrSPIBaud		= errors.New("SPI baud too low or above 66.5Mhz")
	errSPIInvalidSDI	= errors.New("invalid SPI SDI pin")
	errSPIInvalidSDO	= errors.New("invalid SPI SDO pin")
	errSPIInvalidSCK	= errors.New("invalid SPI SCK pin")
var Watchdog = &watchdogImpl{}

Watchdog provides access to the hardware watchdog available in the RP2040.

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 CPUFrequency

func CPUFrequency() uint32

func CPUReset

func CPUReset()

CPUReset performs a hard system reset.

func ChipVersion

func ChipVersion() uint8

ChipVersion returns the version of the chip. 1 is returned for B0 and B1 chip.

func ConfigureUSBEndpoint

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

func CurrentCore

func CurrentCore() int

CurrentCore returns the core number the call was made from.

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 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 GetRNG

func GetRNG() (uint32, error)

GetRNG returns 32 bits of semi-random data based on ring oscillator.

Unlike some other implementations of GetRNG, these random numbers are not cryptographically secure and must not be used for cryptographic operations (nonces, etc).

func InitADC

func InitADC()

InitADC resets the ADC peripheral.

func InitSerial

func InitSerial()

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

func NumCores

func NumCores() int

NumCores returns number of cores available on the device.

func PWMPeripheral

func PWMPeripheral(pin Pin) (sliceNum uint8, err error)

Peripheral returns the RP2040 PWM peripheral which ranges from 0 to 7. Each PWM peripheral has 2 channels, A and B which correspond to 0 and 1 in the program. This number corresponds to the package’s PWM0 throughout PWM7 handles

func ReadTemperature

func ReadTemperature() (millicelsius int32)

ReadTemperature does a one-shot sample of the internal temperature sensor and returns a milli-celsius reading.

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) error

Configure sets the ADC pin to analog input mode.

func (ADC) Get

func (a ADC) Get() uint16

Get returns a one-shot ADC sample reading.

func (ADC) GetADCChannel

func (a ADC) GetADCChannel() (c ADCChannel, err error)

GetADCChannel returns the channel associated with the ADC pin.

type ADCChannel

type ADCChannel uint8

ADCChannel is the ADC peripheral mux channel. 0-4.

func (ADCChannel) Configure

func (c ADCChannel) Configure(config ADCConfig) error

Configure sets the channel’s associated pin to analog input mode. The powered on temperature sensor increases ADC_AVDD current by approximately 40 μA.

func (ADCChannel) Pin

func (c ADCChannel) Pin() (p Pin, err error)

The Pin method returns the GPIO Pin associated with the ADC mux channel, if it has one.

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.

	// WriteAt writes the given number of bytes to the block device.

	// 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		*rp.I2C0_Type
	mode		I2CMode
	txInProgress	bool

func (*I2C) Configure

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

Configure initializes i2c peripheral and configures I2C config’s pins passed. Here’s a list of valid SDA and SCL GPIO pins on bus I2C0 of the rp2040:

SDA: 0, 4, 8, 12, 16, 20
SCL: 1, 5, 9, 13, 17, 21

Same as above for I2C1 bus:

SDA: 2, 6, 10, 14, 18, 26
SCL: 3, 7, 11, 15, 19, 27

func (*I2C) Listen

func (i2c *I2C) Listen(addr uint16) error

Listen starts listening for I2C requests sent to specified address

addr is the address to listen to

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) Reply

func (i2c *I2C) Reply(buf []byte) error

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) error

Tx performs a write and then a read transfer placing the result in in r.

Passing a nil value for w or r skips the transfer corresponding to write or read, respectively.

i2c.Tx(addr, nil, r)

Performs only a read transfer.

i2c.Tx(addr, w, nil)

Performs only a write transfer.

func (*I2C) WaitForEvent

func (i2c *I2C) WaitForEvent(buf []byte) (evt I2CTargetEvent, count int, err error)

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
	// SDA/SCL Serial Data and clock pins. Refer to datasheet to see
	// which pins match the desired bus.
	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 configures the gpio pin as per mode.

func (Pin) Get

func (p Pin) Get() bool

Get reads the pin value.

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)

func (Pin) PortMaskSet

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

func (Pin) Set

func (p Pin) Set(value bool)

Set drives the pin high if value is true else drives it low.

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

PinChange represents one or more trigger events that can happen on a given GPIO pin on the RP2040. ORed PinChanges are valid input to most IRQ functions.

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

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 *rp.SPI0_Type

func (SPI) Configure

func (spi SPI) Configure(config SPIConfig) error

Configure is intended to setup/initialize the SPI interface. Default baudrate of 4MHz is used if Frequency == 0. Default word length (data bits) is 8. Below is a list of GPIO pins corresponding to SPI0 bus on the rp2040:

SI : 0, 4, 17  a.k.a RX and MISO (if rp2040 is master)
SO : 3, 7, 19  a.k.a TX and MOSI (if rp2040 is master)
SCK: 2, 6, 18

SPI1 bus GPIO pins:

SI : 8, 12
SO : 11, 15
SCK: 10, 14

No pin configuration is needed of SCK, SDO and SDI needed after calling Configure.

func (SPI) GetBaudRate

func (spi SPI) GetBaudRate() uint32

func (SPI) PrintRegs

func (spi SPI) PrintRegs()

PrintRegs prints SPI’s peripheral common registries current values

func (SPI) SetBaudRate

func (spi SPI) SetBaudRate(br uint32) error

func (SPI) Transfer

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

Write a single byte and read a single byte from TX/RX FIFO.

func (SPI) Tx

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

Remark: This implementation (RP2040) allows reading into buffer with a custom repeated value on tx.

spi.Tx([]byte{0xff}, rx) // may cause unwanted heap allocations.

This form sends 0xff and puts the result into rx buffer. Useful for reading from SD cards which require 0xff input on SI.

type SPIConfig

type SPIConfig struct {
	Frequency	uint32
	// LSB not supported on rp2040.
	LSBFirst	bool
	// Mode's two most LSB are CPOL and CPHA. i.e. Mode==2 (0b10) is CPOL=1, CPHA=0
	Mode	uint8
	// Serial clock pin
	SCK	Pin
	// TX or Serial Data Out (MOSI if rp2040 is master)
	SDO	Pin
	// RX or Serial Data In (MISO if rp2040 is master)
	SDI	Pin

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 UART

type UART struct {
	Buffer		*RingBuffer
	Bus		*rp.UART0_Type
	Interrupt	interrupt.Interrupt

UART on the RP2040.

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 baudrate to be used for the UART.

func (*UART) SetFormat

func (uart *UART) SetFormat(databits, stopbits uint8, parity UARTParity) error

SetFormat for number of data bits, stop bits, and parity 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 USBBuffer

type USBBuffer struct {
	Buffer0	[USBBufferLen]byte
	Buffer1	[USBBufferLen]byte

type USBBufferControlRegister

type USBBufferControlRegister struct {
	In	volatile.Register32
	Out	volatile.Register32


type USBDPSRAM struct {
	// Note that EPxControl[0] is not EP0Control but 8-byte setup data.
	EPxControl	[16]USBEndpointControlRegister

	EPxBufferControl	[16]USBBufferControlRegister

	EPxBuffer	[16]USBBuffer

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 USBEndpointControlRegister

type USBEndpointControlRegister struct {
	In	volatile.Register32
	Out	volatile.Register32

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 April 17, 2024: Fix doc-gen and update docs (8a74a2b)