Documentation
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Index ¶
Constants ¶
const ( Mode0 = 0 Mode1 = 1 Mode2 = 2 Mode3 = 3 )
SPI phase and polarity configs CPOL and CPHA
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 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).
Variables ¶
var ( ErrTimeoutRNG = errors.New("machine: RNG Timeout") 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 = &UART{0} USB = &UART{100} )
var ( SPI0 = SPI{0} I2C0 = &I2C{0} )
var (
ErrPWMPeriodTooLong = errors.New("pwm: period too long")
)
var (
ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
)
var Serial = UART0
The Serial port always points to the default UART in a simulated environment.
TODO: perhaps this should be a special serial object that outputs via WASI stdout calls.
Functions ¶
Types ¶
type ADC ¶
type ADC struct {
Pin Pin
}
type ADCConfig ¶ added in v0.17.0
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)
}
ADCConfig holds ADC configuration parameters. If left unspecified, the zero value of each parameter will use the peripheral's default settings.
type I2C ¶ added in v0.7.0
type I2C struct {
Bus uint8
}
I2C is a generic implementation of the Inter-IC communication protocol.
type NullSerial ¶ added in v0.19.0
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 ¶ added in v0.19.0
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 ¶ added in v0.19.0
func (ns NullSerial) Configure(config UARTConfig) error
Configure does nothing: the null serial has no configuration.
func (NullSerial) ReadByte ¶ added in v0.19.0
func (ns NullSerial) ReadByte() (byte, error)
ReadByte always returns an error because there aren't any bytes to read.
func (NullSerial) Write ¶ added in v0.19.0
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 ¶ added in v0.19.0
func (ns NullSerial) WriteByte(b byte) error
WriteByte is a no-op: the null serial doesn't write bytes.
type PWMConfig ¶ added in v0.18.0
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 ¶ added in v0.6.0
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) High ¶ added in v0.6.0
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.
type PinMode ¶ added in v0.6.0
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 {
// contains filtered or unexported fields
}
RingBuffer is ring buffer implementation inspired by post at https://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php
func (*RingBuffer) Clear ¶ added in v0.14.0
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 ¶ added in v0.7.0
type SPI struct {
Bus uint8
}
func (SPI) Tx ¶ added in v0.7.0
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 UART ¶ added in v0.7.0
type UART struct {
Bus uint8
}
func (*UART) Buffered ¶ added in v0.7.0
Buffered returns the number of bytes currently stored in the RX buffer.
func (*UART) Configure ¶ added in v0.7.0
func (uart *UART) Configure(config UARTConfig)
Configure the UART.
type UARTConfig ¶ added in v0.7.0
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.
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