IoExpanderSPI Class Reference

Software SPI master class for driving GPIO expanders via bit-banging. More...

#include <IoExpanderSPI.hpp>

Public Member Functions
	IoExpanderSPI ()
	Construct a new IoExpanderSPI object.
	~IoExpanderSPI ()=default
	Destroy the IoExpanderSPI object.
bool	beginSPI (IoExpanderBase &base, int mosi, int miso, int sck, int cs)
	Initialize the software SPI interface.
void	setBitOrder (uint8_t order)
	Set the bit order for SPI transfers.
uint8_t	transfer8 (uint8_t val)
	Transfer 8 bits over SPI.
uint16_t	transfer9 (uint16_t val)
	Transfer 9 bits over SPI.
uint32_t	transferDataBits (uint32_t val, uint32_t bits)
	Transfer an arbitrary number of bits over SPI.

Detailed Description

Software SPI master class for driving GPIO expanders via bit-banging.

This class implements a software SPI master using the pin control functions provided by any IoExpanderBase-derived class. It allows expanders without dedicated hardware SPI to be controlled via general-purpose I/O pins.

Definition at line 44 of file IoExpanderSPI.hpp.

Constructor & Destructor Documentation

IoExpanderSPI()

IoExpanderSPI::IoExpanderSPI ( )

inline

Construct a new IoExpanderSPI object.

Initializes all pin numbers to -1 (unused) and bit order to 0 (MSB first).

Definition at line 52 of file IoExpanderSPI.hpp.

~IoExpanderSPI()

IoExpanderSPI::~IoExpanderSPI ( )

default

Destroy the IoExpanderSPI object.

Member Function Documentation

beginSPI()

bool IoExpanderSPI::beginSPI ( IoExpanderBase &  base, int  mosi, int  miso, int  sck, int  cs  )

inline

Initialize the software SPI interface.

Configures the specified pins for SPI operation using the provided expander instance. MOSI and SCK are mandatory and set as outputs; CS is optional (if not -1) and set as output high; MISO is optional and set as input if provided.

Parameters

base	Reference to the IoExpanderBase instance used for pin control.
mosi	MOSI pin number (must be specified).
miso	MISO pin number (set to -1 if not used).
sck	SCK pin number (must be specified).
cs	Chip select pin number (set to -1 if not used).

Returns

true Initialization successful.

false Initialization failed (e.g., missing MOSI or SCK).

Definition at line 75 of file IoExpanderSPI.hpp.

References IoExpanderBase::digitalWrite(), IoExpanderBase::pinMode(), and SENSORLIB_LOG_E.

setBitOrder()

void IoExpanderSPI::setBitOrder ( uint8_t  order )

inline

Set the bit order for SPI transfers.

Parameters

order

0 for MSB first, 1 for LSB first. Only the least significant bit is used; any other bits are ignored.

Definition at line 110 of file IoExpanderSPI.hpp.

transfer8()

uint8_t IoExpanderSPI::transfer8 ( uint8_t  val )

inline

Transfer 8 bits over SPI.

Parameters

val	8-bit data to send.

Returns

uint8_t 8-bit data received.

Definition at line 121 of file IoExpanderSPI.hpp.

References transferDataBits().

transfer9()

uint16_t IoExpanderSPI::transfer9 ( uint16_t  val )

inline

Transfer 9 bits over SPI.

Useful for devices requiring 9-bit transfers (e.g., certain sensors).

Parameters

val	9-bit data to send (only lower 9 bits are used).

Returns

uint16_t 9-bit data received (only lower 9 bits are valid).

Definition at line 134 of file IoExpanderSPI.hpp.

References transferDataBits().

transferDataBits()

uint32_t IoExpanderSPI::transferDataBits ( uint32_t  val, uint32_t  bits  )

inline

Transfer an arbitrary number of bits over SPI.

Performs a full-duplex software SPI transfer of the specified number of bits. The data is shifted out MSB-first or LSB-first according to the current bit order.

Parameters

val	Data to send (only the lower 'bits' bits are used).
bits	Number of bits to transfer (1-32).

Returns

uint32_t Data received (only the lower 'bits' bits are valid).

Definition at line 149 of file IoExpanderSPI.hpp.

References IoExpanderBase::digitalRead(), IoExpanderBase::digitalWrite(), i, and SENSORLIB_LOG_E.

Referenced by transfer8(), and transfer9().

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

• IoExpanderSPI.hpp