const (
	// Arduino Pins
	A0	= PA0
	A1	= PA1
	A2	= PA3
	A3	= PA4
	A4	= PA5
	A5	= PA6
	A6	= PA7
	A7	= PA2

	D0	= PA10
	D1	= PA9
	D2	= PA12
	D3	= PB0
	D4	= PB7
	D5	= PB6
	D6	= PB1
	D7	= PC14
	D8	= PC15
	D9	= PA8
	D10	= PA11
	D11	= PB5
	D12	= PB4
	D13	= PB3
const (
const (
	// This board does not have a user button, so
	// use first GPIO pin by default
const (
	// UART pins
	// PA2 and PA15 are connected to the ST-Link Virtual Com Port (VCP)

	// I2C pins
	// With default solder bridge settings:
	//    PB6 / Arduino D5 / CN3 Pin 8 is SCL
	//    PB7 / Arduino D4 / CN3 Pin 7 is SDA

	// 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.

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 (
	PinRising	PinChange	= 1 << iota
	PinToggle	= PinRising | PinFalling
const (

	// 100ms delay = 100e6ns / 16ns
	// In runtime_stm32_timers.go, tick is fixed at 16ns per tick
	TIMEOUT_TICKS	= 100e6 / 16

	I2C_GENERATE_START_WRITE	= 0x80000000 | stm32.I2C_CR2_START
	I2C_GENERATE_START_READ		= 0x80000000 | stm32.I2C_CR2_START | stm32.I2C_CR2_RD_WRN
	I2C_GENERATE_STOP		= 0x80000000 | stm32.I2C_CR2_STOP
const (
	// WatchdogMaxTimeout in milliseconds (32.768s)
	// Timeout is based on 12-bit counter with /256 divider on
	// 32.768kHz clock.  See 21.3.3 of RM0090 for table.
	WatchdogMaxTimeout = ((0xfff + 1) * 256 * 1024) / 32768
const (
	// Mode Flag
	PinOutput		PinMode	= 0
	PinInput		PinMode	= PinInputFloating
	PinInputFloating	PinMode	= 1
	PinInputPulldown	PinMode	= 2
	PinInputPullup		PinMode	= 3

	// for UART
	PinModeUARTTX	PinMode	= 4
	PinModeUARTRX	PinMode	= 5

	// for I2C
	PinModeI2CSCL	PinMode	= 6
	PinModeI2CSDA	PinMode	= 7

	// for SPI
	PinModeSPICLK	PinMode	= 8
	PinModeSPISDO	PinMode	= 9
	PinModeSPISDI	PinMode	= 10

	// for analog/ADC
	PinInputAnalog	PinMode	= 11

	// for PWM
	PinModePWMOutput	PinMode	= 12
const PWM_MODE1 = 0x6
const (
	AF0_SYSTEM		= 0
	AF1_TIM1_2_LPTIM1	= 1
	AF2_TIM1_2		= 2
	AF3_USART2		= 3
	AF4_I2C1_2_3		= 4
	AF5_SPI1_2		= 5
	AF6_SPI3		= 6
	AF7_USART1_2_3		= 7
	AF8_LPUART1		= 8
	AF9_CAN1_TSC		= 9
	AF12_COMP1_2_SWPMI1	= 12
	AF13_SAI1		= 13
	AF14_TIM2_15_16_LPTIM2	= 14
	AF15_EVENTOUT		= 15
const (
	PA0	= portA + 0
	PA1	= portA + 1
	PA2	= portA + 2
	PA3	= portA + 3
	PA4	= portA + 4
	PA5	= portA + 5
	PA6	= portA + 6
	PA7	= portA + 7
	PA8	= portA + 8
	PA9	= portA + 9
	PA10	= portA + 10
	PA11	= portA + 11
	PA12	= portA + 12
	PA13	= portA + 13
	PA14	= portA + 14
	PA15	= portA + 15

	PB0	= portB + 0
	PB1	= portB + 1
	PB2	= portB + 2
	PB3	= portB + 3
	PB4	= portB + 4
	PB5	= portB + 5
	PB6	= portB + 6
	PB7	= portB + 7
	PB8	= portB + 8
	PB9	= portB + 9
	PB10	= portB + 10
	PB11	= portB + 11
	PB12	= portB + 12
	PB13	= portB + 13
	PB14	= portB + 14
	PB15	= portB + 15

	PC0	= portC + 0
	PC1	= portC + 1
	PC2	= portC + 2
	PC3	= portC + 3
	PC4	= portC + 4
	PC5	= portC + 5
	PC6	= portC + 6
	PC7	= portC + 7
	PC8	= portC + 8
	PC9	= portC + 9
	PC10	= portC + 10
	PC11	= portC + 11
	PC12	= portC + 12
	PC13	= portC + 13
	PC14	= portC + 14
	PC15	= portC + 15

	PD0	= portD + 0
	PD1	= portD + 1
	PD2	= portD + 2
	PD3	= portD + 3
	PD4	= portD + 4
	PD5	= portD + 5
	PD6	= portD + 6
	PD7	= portD + 7
	PD8	= portD + 8
	PD9	= portD + 9
	PD10	= portD + 10
	PD11	= portD + 11
	PD12	= portD + 12
	PD13	= portD + 13
	PD14	= portD + 14
	PD15	= portD + 15

	PE0	= portE + 0
	PE1	= portE + 1
	PE2	= portE + 2
	PE3	= portE + 3
	PE4	= portE + 4
	PE5	= portE + 5
	PE6	= portE + 6
	PE7	= portE + 7
	PE8	= portE + 8
	PE9	= portE + 9
	PE10	= portE + 10
	PE11	= portE + 11
	PE12	= portE + 12
	PE13	= portE + 13
	PE14	= portE + 14
	PE15	= portE + 15
const (
	ARR_MAX	= 0x10000
	PSC_MAX	= 0x10000
const APB1_TIM_FREQ = 80e6	// 80MHz

Internal use: configured speed of the APB1 and APB2 timers, this should be kept in sync with any changes to runtime package which configures the oscillators and clock frequencies

const APB2_TIM_FREQ = 80e6	// 80MHz
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 (
	// USART2 is the hardware serial port connected to the onboard ST-LINK
	// debugger to be exposed as virtual COM port over USB on Nucleo boards.
	UART1	= &_UART1
		Buffer:			NewRingBuffer(),
		Bus:			stm32.USART2,
		TxAltFuncSelector:	7,
		RxAltFuncSelector:	3,
	DefaultUART	= UART1

	// I2C1 is documented, alias to I2C0 as well
	I2C1	= &I2C{
		Bus:			stm32.I2C1,
		AltFuncSelector:	4,
	I2C0	= I2C1

	// SPI1 is documented, alias to SPI0 as well
	SPI1	= &SPI{
		Bus:			stm32.SPI1,
		AltFuncSelector:	5,
	SPI0	= SPI1
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 (
	Watchdog = &watchdogImpl{}
var (
	TIM1	= TIM{
		EnableRegister:	&stm32.RCC.APB2ENR,
		EnableFlag:	stm32.RCC_APB2ENR_TIM1EN,
		Device:		stm32.TIM1,
		Channels: [4]TimerChannel{
			TimerChannel{Pins: []PinFunction{
				{PA8, AF1_TIM1_2_LPTIM1},
			TimerChannel{Pins: []PinFunction{
				{PA9, AF1_TIM1_2_LPTIM1},
			TimerChannel{Pins: []PinFunction{
				{PA10, AF1_TIM1_2_LPTIM1},
			TimerChannel{Pins: []PinFunction{
				{PA11, AF1_TIM1_2_LPTIM1},
		busFreq:	APB2_TIM_FREQ,

	TIM2	= TIM{
		EnableRegister:	&stm32.RCC.APB1ENR1,
		EnableFlag:	stm32.RCC_APB1ENR1_TIM2EN,
		Device:		stm32.TIM2,
		Channels: [4]TimerChannel{
			TimerChannel{Pins: []PinFunction{
				{PA0, AF1_TIM1_2_LPTIM1},
				{PA5, AF1_TIM1_2_LPTIM1},
				{PA15, AF1_TIM1_2_LPTIM1},
			TimerChannel{Pins: []PinFunction{
				{PA1, AF1_TIM1_2_LPTIM1},
				{PB3, AF1_TIM1_2_LPTIM1},
			TimerChannel{Pins: []PinFunction{
				{PA2, AF1_TIM1_2_LPTIM1},
			TimerChannel{Pins: []PinFunction{
				{PA3, AF1_TIM1_2_LPTIM1},
		busFreq:	APB1_TIM_FREQ,

	TIM3	= TIM{
		EnableRegister:	&stm32.RCC.APB1ENR1,
		EnableFlag:	stm32.RCC_APB1ENR1_TIM3EN,
		Device:		stm32.TIM3,
		Channels: [4]TimerChannel{
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
		busFreq:	APB1_TIM_FREQ,

	TIM6	= TIM{
		EnableRegister:	&stm32.RCC.APB1ENR1,
		EnableFlag:	stm32.RCC_APB1ENR1_TIM6EN,
		Device:		stm32.TIM6,
		Channels: [4]TimerChannel{
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
		busFreq:	APB1_TIM_FREQ,

	TIM7	= TIM{
		EnableRegister:	&stm32.RCC.APB1ENR1,
		EnableFlag:	stm32.RCC_APB1ENR1_TIM7EN,
		Device:		stm32.TIM7,
		Channels: [4]TimerChannel{
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
		busFreq:	APB1_TIM_FREQ,

	TIM15	= TIM{
		EnableRegister:	&stm32.RCC.APB2ENR,
		EnableFlag:	stm32.RCC_APB2ENR_TIM15EN,
		Device:		stm32.TIM15,
		Channels: [4]TimerChannel{
			TimerChannel{Pins: []PinFunction{
				{PA2, AF14_TIM2_15_16_LPTIM2},
			TimerChannel{Pins: []PinFunction{
				{PA3, AF14_TIM2_15_16_LPTIM2},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
		busFreq:	APB2_TIM_FREQ,

	TIM16	= TIM{
		EnableRegister:	&stm32.RCC.APB2ENR,
		EnableFlag:	stm32.RCC_APB2ENR_TIM16EN,
		Device:		stm32.TIM16,
		Channels: [4]TimerChannel{
			TimerChannel{Pins: []PinFunction{
				{PA6, AF14_TIM2_15_16_LPTIM2},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
			TimerChannel{Pins: []PinFunction{}},
		busFreq:	APB2_TIM_FREQ,
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.

The length of the device ID for STM32 is 12 bytes (96 bits).

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 cryptographically secure random data

func InitSerial

func InitSerial()

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

type ADC

type ADC struct {
	Pin Pin

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 ChannelCallback

type ChannelCallback func(channel uint8)

type I2C

type I2C struct {
	Bus		*stm32.I2C_Type
	AltFuncSelector	uint8

func (*I2C) Configure

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

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 communication speed for I2C.

func (*I2C) Tx

func (i2c *I2C) Tx(addr uint16, w, r []byte) 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 {
	SCL	Pin
	SDA	Pin

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) ConfigureAltFunc

func (p Pin) ConfigureAltFunc(config PinConfig, altFunc uint8)

Configure this pin with the given configuration including alternate

function mapping if necessary.

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)

PortMaskClear returns 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)

PortMaskSet returns 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) SetAltFunc

func (p Pin) SetAltFunc(af uint8)

SetAltFunc maps the given alternative function to the I/O 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

———- General pin operations ———-

type PinConfig

type PinConfig struct {
	Mode PinMode

type PinFunction

type PinFunction struct {
	Pin	Pin
	AltFunc	uint8

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		*stm32.SPI_Type
	AltFuncSelector	uint8

SPI on the STM32Fxxx using MODER / alternate function pins

func (SPI) Configure

func (spi SPI) Configure(config SPIConfig) error

Configure is intended to setup the STM32 SPI1 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
	SDO		Pin
	SDI		Pin
	LSBFirst	bool
	Mode		uint8

SPIConfig is used to store config info for SPI.

type TIM

type TIM struct {
	EnableRegister	*volatile.Register32
	EnableFlag	uint32
	Device		*stm32.TIM_Type
	Channels	[4]TimerChannel
	UpInterrupt	interrupt.Interrupt
	OCInterrupt	interrupt.Interrupt

	wraparoundCallback	TimerCallback
	channelCallbacks	[4]ChannelCallback

	busFreq	uint64

func (*TIM) Channel

func (t *TIM) Channel(pin Pin) (uint8, error)

Channel returns a PWM channel for the given pin.

func (*TIM) Configure

func (t *TIM) Configure(config PWMConfig) error

Configure enables and configures this PWM.

func (*TIM) Count

func (t *TIM) Count() uint32

func (*TIM) Set

func (t *TIM) Set(channel uint8, value uint32)

Set updates the channel value. This is used to control the channel duty cycle. For example, to set it to a 25% duty cycle, use:

t.Set(ch, t.Top() / 4)

ch.Set(0) will set the output to low and ch.Set(ch.Top()) will set the output to high, assuming the output isn’t inverted.

func (*TIM) SetInverting

func (t *TIM) SetInverting(channel uint8, inverting bool)

SetInverting sets whether to invert the output of this channel. Without inverting, a 25% duty cycle would mean the output is high for 25% of the time and low for the rest. Inverting flips the output as if a NOT gate was placed at the output, meaning that the output would be 25% low and 75% high with a duty cycle of 25%.

func (*TIM) SetMatchInterrupt

func (t *TIM) SetMatchInterrupt(channel uint8, callback ChannelCallback) error

Sets a callback to be called when a channel reaches it’s set-point.

For example, if t.Set(ch, t.Top() / 4) is used then the callback will be called every quarter-period of the timer’s base Period.

func (*TIM) SetPeriod

func (t *TIM) SetPeriod(period uint64) error

SetPeriod updates the period of this PWM peripheral. To set a particular frequency, use the following formula:

period = 1e9 / frequency

If you use a period of 0, a period that works well for LEDs will be picked.

SetPeriod will not change the prescaler, but also won’t change the current value in any of the channels. This means that you may need to update the value for the particular channel.

Note that you cannot pick any arbitrary period after the PWM peripheral has been configured. If you want to switch between frequencies, pick the lowest frequency (longest period) once when calling Configure and adjust the frequency here as needed.

func (*TIM) SetWraparoundInterrupt

func (t *TIM) SetWraparoundInterrupt(callback TimerCallback) error

SetWraparoundInterrupt configures a callback to be called each time the timer ‘wraps-around’.

For example, if Configure(PWMConfig{Period:1000000}) is used, to set the timer period to 1ms, this callback will be called every 1ms.

func (*TIM) Top

func (t *TIM) Top() uint32

Top returns the current counter top, for use in duty cycle calculation. It will only change with a call to Configure or SetPeriod, otherwise it is constant.

The value returned here is hardware dependent. In general, it’s best to treat it as an opaque value that can be divided by some number and passed to pwm.Set (see pwm.Set for more information).

func (*TIM) Unset

func (t *TIM) Unset(channel uint8)

Unset disables a channel, including any configured interrupts.

type TimerCallback

type TimerCallback func()

type TimerChannel

type TimerChannel struct {
	Pins []PinFunction

type UART

type UART struct {
	Buffer			*RingBuffer
	Bus			*stm32.USART_Type
	Interrupt		interrupt.Interrupt
	TxAltFuncSelector	uint8
	RxAltFuncSelector	uint8

	// Registers specific to the chip
	rxReg		*volatile.Register32
	txReg		*volatile.Register32
	statusReg	*volatile.Register32
	txEmptyFlag	uint32

UART representation

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. Defer to chip-specific routines for calculation

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 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)