xiao-rp2040
Constants
const (
D0 Pin = GPIO26
D1 Pin = GPIO27
D2 Pin = GPIO28
D3 Pin = GPIO29
D4 Pin = GPIO6
D5 Pin = GPIO7
D6 Pin = GPIO0
D7 Pin = GPIO1
D8 Pin = GPIO2
D9 Pin = GPIO4
D10 Pin = GPIO3
)
Digital Pins
const (
A0 Pin = D0
A1 Pin = D1
A2 Pin = D2
A3 Pin = D3
)
Analog pins
const (
NEOPIXEL = GPIO12
WS2812 = GPIO12
NEO_PWR = GPIO11
NEOPIXEL_POWER = GPIO11
LED = GPIO17
LED_RED = GPIO17
LED_GREEN = GPIO16
LED_BLUE = GPIO25
)
Onboard LEDs
const (
I2C0_SDA_PIN Pin = D2
I2C0_SCL_PIN Pin = D3
I2C1_SDA_PIN Pin = D4
I2C1_SCL_PIN Pin = D5
)
I2C pins
const (
SPI0_SCK_PIN Pin = D8
SPI0_SDO_PIN Pin = D10
SPI0_SDI_PIN Pin = D9
SPI1_SCK_PIN Pin = NoPin
SPI1_SDO_PIN Pin = NoPin
SPI1_SDI_PIN Pin = NoPin
)
SPI pins
const (
UART0_TX_PIN = GPIO0
UART0_RX_PIN = GPIO1
UART_TX_PIN = UART0_TX_PIN
UART_RX_PIN = UART0_RX_PIN
)
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.
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 (
PinOutput PinMode = iota
PinInput
PinInputPulldown
PinInputPullup
PinAnalog
PinUART
PinPWM
PinI2C
PinSPI
PinPIO0
PinPIO1
)
const (
// Edge falling
PinFalling PinChange = 4 << iota
// Edge rising
PinRising
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
)
const XOSC_STARTUP_DELAY_MULTIPLIER = 64
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.
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 Flash flashBlockDevice
var (
UART0 = &_UART0
_UART0 = UART{
Buffer: NewRingBuffer(),
Bus: rp.UART0,
}
UART1 = &_UART1
_UART1 = UART{
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.
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 *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.
SDA, SCL 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 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 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 *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 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)
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
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.