PhyduinoWire Class Reference

I2C controller or peripheral on one RP2040 I2C peripheral; sketches use Wire. More...

#include <Wire.h>

Inheritance diagram for PhyduinoWire:

Public Member Functions
	PhyduinoWire (i2c_inst_t *i2c, pin_size_t sda, pin_size_t scl)
	Binds Wire to an I2C peripheral and its pins; nothing is set up until begin().
void	begin () override
	Starts as a controller, at 100 kHz unless setClock() was called.
void	begin (uint8_t address) override
	Starts as a peripheral that answers at address.
void	end () override
	Stops I2C and frees the pins.
void	setClock (uint32_t hz) override
	Sets the bus clock; applies at once if already started.
Controller
void	beginTransmission (uint8_t address) override
	Starts a write to a device; queue the bytes with write().
uint8_t	endTransmission (bool sendStop) override
	Sends the queued bytes.
uint8_t	endTransmission () override
	Sends the queued bytes and ends with a stop.
size_t	requestFrom (uint8_t address, size_t length, bool sendStop) override
	Reads bytes from a device into the receive buffer; take them with read().
size_t	requestFrom (uint8_t address, size_t length) override
	Reads bytes from a device and ends with a stop.
Data (controller and peripheral)
size_t	write (uint8_t data) override
	Queues one byte: for endTransmission(), or as the reply in onRequest().
size_t	write (const uint8_t *data, size_t length) override
	Queues several bytes: for endTransmission(), or as the reply in onRequest().
int	available () override
	Number of received bytes waiting to be read.
int	read () override
	Takes the next received byte.
int	peek () override
	Next received byte, left in the buffer.
void	flush () override
	Does nothing; kept for Arduino compatibility.
Peripheral
The callbacks run inside the I2C interrupt: keep them short.
void	onReceive (void(*callback)(int)) override
	Sets the function called after a controller has written to this board.
void	onRequest (void(*callback)()) override
	Sets the function called when a controller reads from this board.

Static Public Attributes
static constexpr size_t	kBufferSize = 256
	Largest number of bytes in one transmission or request.

Detailed Description

I2C controller or peripheral on one RP2040 I2C peripheral; sketches use Wire.

Every transfer gives up after 50 ms if the bus is stuck.

Constructor & Destructor Documentation

PhyduinoWire()

PhyduinoWire::PhyduinoWire ( i2c_inst_t * i2c, pin_size_t sda, pin_size_t scl )

inline

Binds Wire to an I2C peripheral and its pins; nothing is set up until begin().

Parameters

i2c	pico-sdk I2C (i2c0 or i2c1).
sda	Arduino pin for SDA.
scl	Arduino pin for SCL.

Member Function Documentation

available()

int PhyduinoWire::available ( )

override

Number of received bytes waiting to be read.

Returns

Byte count.

begin()

void PhyduinoWire::begin ( uint8_t address )

override

Starts as a peripheral that answers at address.

Set onReceive() and onRequest() first.

Parameters

address

7-bit address, 0x08-0x77.

beginTransmission()

void PhyduinoWire::beginTransmission ( uint8_t address )

override

Starts a write to a device; queue the bytes with write().

Parameters

address

7-bit device address.

endTransmission() [1/2]

uint8_t PhyduinoWire::endTransmission ( )

inlineoverride

Sends the queued bytes and ends with a stop.

Returns

As endTransmission(bool).

endTransmission() [2/2]

uint8_t PhyduinoWire::endTransmission ( bool sendStop )

override

Sends the queued bytes.

With no bytes queued it only checks that the device answers, which is what I2C scanners use.

Parameters

sendStop

true to end with a stop; false to keep the bus for a following requestFrom() (repeated start).

Returns

0 on success, 2 if the device did not answer, 5 on timeout, 4 on any other error.

onReceive()

void PhyduinoWire::onReceive ( void(* callback )(int) )

inlineoverride

Sets the function called after a controller has written to this board.

Parameters

callback

Function taking the number of bytes received; read them with read().

onRequest()

void PhyduinoWire::onRequest ( void(* callback )() )

inlineoverride

Sets the function called when a controller reads from this board.

Parameters

callback

Function that queues the reply with write().

peek()

int PhyduinoWire::peek ( )

override

Next received byte, left in the buffer.

Returns

0-255, or -1 if there is none.

read()

int PhyduinoWire::read ( )

override

Takes the next received byte.

Returns

0-255, or -1 if there is none.

requestFrom() [1/2]

size_t PhyduinoWire::requestFrom ( uint8_t address, size_t length )

inlineoverride

Reads bytes from a device and ends with a stop.

Parameters

address	7-bit device address.
length	Number of bytes, at most kBufferSize.

Returns

Number of bytes received, 0 on error.

requestFrom() [2/2]

size_t PhyduinoWire::requestFrom ( uint8_t address, size_t length, bool sendStop )

override

Reads bytes from a device into the receive buffer; take them with read().

Parameters

address	7-bit device address.
length	Number of bytes, at most kBufferSize.
sendStop	true to end with a stop; false to keep the bus.

Returns

Number of bytes received, 0 on error.

setClock()

void PhyduinoWire::setClock ( uint32_t hz )

override

Sets the bus clock; applies at once if already started.

Parameters

hz	Clock in Hz, usually 100000 or 400000.

write() [1/2]

size_t PhyduinoWire::write ( const uint8_t * data, size_t length )

override

Queues several bytes: for endTransmission(), or as the reply in onRequest().

Parameters

data	Bytes to queue.
length	Number of bytes.

Returns

Number of bytes queued; fewer than length if the buffer is full.

write() [2/2]

size_t PhyduinoWire::write ( uint8_t data )

override

Queues one byte: for endTransmission(), or as the reply in onRequest().

Parameters

data	Byte to queue.

Returns

1, or 0 if the buffer is full.

---

The documentation for this class was generated from the following file:

• Wire.h