XPointDriver implementation for the MCP23017 16-bit I2C GPIO expander. More...

#include <MCP23017Driver.h>

Inheritance diagram for MCP23017Driver:

Public Types
typedef uint8_t(*	MapFn) (uint8_t r, uint8_t c)
	Function pointer type: `(row, col) → MCP23017 pin index 0–15`.

Public Member Functions
	MCP23017Driver (I2CInterface *i2c, uint8_t addr, MapFn map)
	Construct the driver.

void	begin () override
	Set IODIRA and IODIRB to 0x00 (all outputs) then write OLATA/OLATB.

void	setNodeHardware (uint8_t r, uint8_t c, bool state) override
	Set or clear one output pin and immediately write both OLAT registers.

void	commitPhysicalUpdates () override
	No-op — MCP23017 writes commit inside setNodeHardware().

uint8_t	gpioA () const
	Read the OLATA shadow register (for diagnostics / testing).

uint8_t	gpioB () const
	Read the OLATB shadow register (for diagnostics / testing).

Public Member Functions inherited from XPointDriver
virtual	~XPointDriver ()

virtual void	setNodeLevel (uint8_t r, uint8_t c, uint16_t level)
	Set an analog drive level for node (r, c).

virtual void	releaseNode (uint8_t, uint8_t)
	De-energize the coil that was pulsed on node (r, c).

Detailed Description

XPointDriver implementation for the MCP23017 16-bit I2C GPIO expander.

Maintains shadow copies of OLATA and OLATB to minimize I2C transactions; both registers are written atomically on each setNodeHardware() call.

Member Typedef Documentation

◆ MapFn

typedef uint8_t(* MCP23017Driver::MapFn) (uint8_t r, uint8_t c)

Function pointer type: (row, col) → MCP23017 pin index 0–15.

Constructor & Destructor Documentation

◆ MCP23017Driver()

MCP23017Driver::MCP23017Driver	(	I2CInterface *	i2c,
		uint8_t	addr,
		MapFn	map
	)

Construct the driver.

Parameters

[in]	i2c	I2C bus implementation (WireI2C or MockI2C).
[in]	addr	7-bit device address (0x20–0x27 set by A0–A2 pins).
[in]	map	Mapper; must return pin indices in `[0, 15]`.

Member Function Documentation

◆ begin()

void MCP23017Driver::begin ( )

overridevirtual

Set IODIRA and IODIRB to 0x00 (all outputs) then write OLATA/OLATB.

Must be called before the first setNodeHardware() so the device does not fight the MCU on the bus lines.

Implements XPointDriver.

◆ commitPhysicalUpdates()

void MCP23017Driver::commitPhysicalUpdates ( )

inlineoverridevirtual

No-op — MCP23017 writes commit inside setNodeHardware().

Reimplemented from XPointDriver.

◆ gpioA()

uint8_t MCP23017Driver::gpioA ( ) const

inline

Read the OLATA shadow register (for diagnostics / testing).

Returns: Current shadow value of OLATA.

◆ gpioB()

uint8_t MCP23017Driver::gpioB ( ) const