esp32h2-devkitm-1

Constants

const (
	WS2812 = GPIO8
)

Data pin of the onboard addressable RGB LED. The board has no plain LED.

const (
	BUTTON = GPIO9
)

BOOT button

const (
	UART_TX_PIN	= GPIO24
	UART_RX_PIN	= GPIO23
)

UART pins

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
	PinInput
	PinInputPullup
	PinInputPulldown
	PinAnalog
)

const (
	GPIO0	Pin	= 0
	GPIO1	Pin	= 1
	GPIO2	Pin	= 2
	GPIO3	Pin	= 3
	GPIO4	Pin	= 4
	GPIO5	Pin	= 5
	GPIO6	Pin	= 6
	GPIO7	Pin	= 7
	GPIO8	Pin	= 8
	GPIO9	Pin	= 9
	GPIO10	Pin	= 10
	GPIO11	Pin	= 11
	GPIO12	Pin	= 12
	GPIO13	Pin	= 13
	GPIO14	Pin	= 14
	GPIO15	Pin	= 15
	GPIO16	Pin	= 16
	GPIO17	Pin	= 17
	GPIO18	Pin	= 18
	GPIO19	Pin	= 19
	GPIO20	Pin	= 20
	GPIO21	Pin	= 21
	GPIO22	Pin	= 22
	GPIO23	Pin	= 23
	GPIO24	Pin	= 24
	GPIO25	Pin	= 25
	GPIO26	Pin	= 26
	GPIO27	Pin	= 27
)

const (
	PinRising	PinChange	= iota + 1
	PinFalling
	PinToggle
)

Pin change interrupt constants for SetInterrupt.

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 (
	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 (
	_USBCDC	= &USB_DEVICE{
		Bus:	esp.USB_DEVICE,
		Buffer:	NewRingBuffer(),
	}

	USBCDC	Serialer	= _USBCDC
)

var USBDev = &USBDevice{}

var (
	DefaultUART	= UART0

	UART0	= &_UART0
	_UART0	= UART{Bus: esp.UART0, Buffer: NewRingBuffer()}
	UART1	= &_UART1
	_UART1	= UART{Bus: esp.UART1, Buffer: NewRingBuffer()}

	onceUart		= sync.Once{}
	errSamePins		= errors.New("UART: invalid pin combination")
	errWrongUART		= errors.New("UART: unsupported UARTn")
	errWrongBitSize		= errors.New("UART: invalid data size")
	errWrongStopBitSize	= errors.New("UART: invalid bit size")
)

var (
	ErrPWMPeriodTooLong = errors.New("pwm: period too long")
)

var Serial = DefaultUART

Serial is implemented via the default (usually the first) UART on the chip.

func CPUFrequency

func CPUFrequency() uint32

CPUFrequency returns the current CPU frequency of the chip. Currently it is a fixed frequency but it may allow changing in the future.

func ConfigureUSBEndpoint

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

ConfigureUSBEndpoint is a no-op on ESP32-C6 and ESP32-H2. The hardware does not support programmable USB endpoints.

func FlushSerial

func FlushSerial()

FlushSerial flushes any pending USB serial TX data.

func InitSerial

func InitSerial()

func NewRingBuffer

func NewRingBuffer() *RingBuffer

NewRingBuffer returns a new ring buffer.

func SendUSBInPacket

func SendUSBInPacket(ep uint32, data []byte) bool

SendUSBInPacket is a no-op on ESP32-C6 and ESP32-H2.

func SendZlp

func SendZlp()

SendZlp is a no-op on ESP32-C6 and ESP32-H2.

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 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 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 GPIO pin. This can be used to implement bit-banged drivers.

Warning: only use this on an output pin!

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.

Warning: only use this on an output pin!

func (Pin) Set

func (p Pin) Set(value 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)) (err 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.

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). If the pin is already configured with a callback, you must first unset this pins interrupt before you can set a new callback.

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 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 {
	Bus			*esp.UART_Type
	Buffer			*RingBuffer
	ParityErrorDetected	bool	// set when parity error detected
	DataErrorDetected	bool	// set when data corruption detected
	DataOverflowDetected	bool	// set when data overflow detected in UART FIFO buffer or RingBuffer
}

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

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(baudRate uint32)

func (*UART) SetFormat

func (uart *UART) SetFormat(dataBits, stopBits int, parity UARTParity) error

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
	InvertTX	bool	// Invert TX line (active low becomes active high, etc.)
	InvertRX	bool	// Invert RX line (active low becomes active high, etc.)
}

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 USBDevice

type USBDevice struct {
	initcomplete		bool
	InitEndpointComplete	bool
}

USBDevice provides a stub USB device for the ESP32-C6 and ESP32-H2. The hardware only supports a fixed-function CDC-ACM serial port, so the programmable USB device features are no-ops.

func (*USBDevice) Attach

func (dev *USBDevice) Attach()

Attach and Detach are no-ops: the USB Serial/JTAG controller has no software-controlled soft-connect, it is always attached to the bus.

func (*USBDevice) ClearStallEPIn

func (dev *USBDevice) ClearStallEPIn(ep uint32)

func (*USBDevice) ClearStallEPOut

func (dev *USBDevice) ClearStallEPOut(ep uint32)

func (*USBDevice) Detach

func (dev *USBDevice) Detach()

func (*USBDevice) SetStallEPIn

func (dev *USBDevice) SetStallEPIn(ep uint32)

func (*USBDevice) SetStallEPOut

func (dev *USBDevice) SetStallEPOut(ep uint32)

type USB_DEVICE

type USB_DEVICE struct {
	Bus		*esp.USB_DEVICE_Type
	Buffer		*RingBuffer
	txPending	bool	// unflushed data in the EP1 TX FIFO
	txStalled	bool	// set when flushAndWait fails (no host reading); cleared when FIFO becomes writable
}

func (*USB_DEVICE) Buffered

func (usbdev *USB_DEVICE) Buffered() int

Buffered returns the number of bytes waiting in the receive ring buffer.

func (*USB_DEVICE) Configure

func (usbdev *USB_DEVICE) Configure(config UARTConfig) error

Configure initialises the USB Serial/JTAG controller clock, pads, and interrupt so that received data is buffered automatically.

func (*USB_DEVICE) DTR

func (usbdev *USB_DEVICE) DTR() bool

func (*USB_DEVICE) RTS

func (usbdev *USB_DEVICE) RTS() bool

func (*USB_DEVICE) ReadByte

func (usbdev *USB_DEVICE) ReadByte() (byte, error)

ReadByte returns a byte from the receive ring buffer.

func (*USB_DEVICE) Write

func (usbdev *USB_DEVICE) Write(data []byte) (n int, err error)

func (*USB_DEVICE) WriteByte

func (usbdev *USB_DEVICE) WriteByte(c byte) error