MCP23017 Class Reference

Inheritance diagram for MCP23017:

Classes
class	RefreshTimer
	This timer runs in the parent executor and upon every timeout it executes the update / polling of the IO expander. More...

Public Types
enum	{ PORTA = 0 , PORTB = 1 }

Public Member Functions
	MCP23017 (ExecutorBase *executor, bool a2, bool a1, bool a0)
	Constructor.
void	init (const char *i2c_path)
	Initializes the device.
void	init (int i2c_fd)
	Initializes the device.

Static Public Attributes
static constexpr long long	POLLING_DELAY = MSEC_TO_NSEC(20)

Private Types
enum	Registers {   IODIRA = 0x0 , IODIRB = 0x1 , IPOLA = 0x2 , IPOLB = 0x3 ,   GPINTENA = 0x4 , GPINTENB = 0x5 , DEFVALA = 0x6 , DEFVALB = 0x7 ,   INTCONA = 0x8 , INTCONB = 0x9 , IOCON = 0xA , GPPUA = 0xC ,   GPPUB = 0xD , INTFA = 0xE , INTFB = 0xF , INTCAPA = 0x10 ,   INTCAPB = 0x11 , RGPIOA = 0x12 , RGPIOB = 0x13 , OLATA = 0x14 ,   OLATB = 0x15 }
enum	{ BASE_ADDRESS = 0b0100000 , DIRTY_DIR = 1 , DIRTY_LAT = 2 }

Private Member Functions
	DISALLOW_COPY_AND_ASSIGN (MCP23017)
void	update_out ()
	Updates the output direction and latch registers if any of it is dirty.
void	update_in ()
	Updates input registers.
void	register_write (uint8_t reg, const uint8_t *data, uint16_t len)
	Writes one or more (sequential) registers in the MCP23017.
void	register_read (uint8_t reg, uint8_t *data, uint16_t len)
	Reads one or more (sequential) registers in the MCP23017.
Private Member Functions inherited from Atomic
void	lock ()
void	unlock ()

Private Attributes
ExecutorBase *	executor_
	Executor. We will be blocking this for the I2C IO.
RefreshTimer	timer_ {this}
	Timer instance to schedule work on the executor.
int	fd_
	I2C port file descriptor.
uint8_t	dir_ [2]
	Shadow of the direction registers.
uint8_t	lat_ [2]
	Shadow of the latch registers.
uint8_t	gpio_ [2]
	Shadow of the input registers.
uint8_t	i2cAddress_
	Address of this particular device on the I2C port.
uint8_t	dirty_ = 0
	Bit mask of registers that need updating.

Friends
class	MCP23017Gpio

Detailed Description

Definition at line 46 of file MCP23017Gpio.hxx.

Member Enumeration Documentation

anonymous enum

anonymous enum

Definition at line 98 of file MCP23017Gpio.hxx.

anonymous enum

anonymous enum

private

Enumerator
BASE_ADDRESS	I2C address of the first device.

Definition at line 134 of file MCP23017Gpio.hxx.

Registers

enum MCP23017::Registers

private

Definition at line 109 of file MCP23017Gpio.hxx.

Constructor & Destructor Documentation

MCP23017()

MCP23017::MCP23017 ( ExecutorBase *  executor, bool  a2, bool  a1, bool  a0  )

inline

Constructor.

Parameters

a2	address bit 2
a1	address bit 1
a0	address bit 0

Definition at line 56 of file MCP23017Gpio.hxx.

Member Function Documentation

init() [1/2]

void MCP23017::init ( const char *  i2c_path )

inline

Initializes the device.

Parameters

i2c_path

is the path to the device driver of the i2c port.

Definition at line 77 of file MCP23017Gpio.hxx.

init() [2/2]

void MCP23017::init ( int  i2c_fd )

inline

Initializes the device.

Parameters

i2c_fd

is the file descriptor of the i2c port to use.

Definition at line 86 of file MCP23017Gpio.hxx.

register_read()

void MCP23017::register_read ( uint8_t  reg, uint8_t *  data, uint16_t  len  )

inlineprivate

Reads one or more (sequential) registers in the MCP23017.

Parameters

reg	starting register offset.
data	where to write payload
len	number of registers to read. Returns when the read is complete.

Definition at line 214 of file MCP23017Gpio.hxx.

register_write()

void MCP23017::register_write ( uint8_t  reg, const uint8_t *  data, uint16_t  len  )

inlineprivate

Writes one or more (sequential) registers in the MCP23017.

Parameters

reg	starting register offset.
data	payload to write
len	number of bytes to write. Returns when the write is complete.

Definition at line 188 of file MCP23017Gpio.hxx.

update_in()

void MCP23017::update_in ( )

inlineprivate

Updates input registers.

Definition at line 178 of file MCP23017Gpio.hxx.

update_out()

void MCP23017::update_out ( )

inlineprivate

Updates the output direction and latch registers if any of it is dirty.

Definition at line 144 of file MCP23017Gpio.hxx.

Friends And Related Symbol Documentation

MCP23017Gpio

friend class MCP23017Gpio

friend

Definition at line 107 of file MCP23017Gpio.hxx.

Member Data Documentation

dir_

uint8_t MCP23017::dir_[2]

private

Shadow of the direction registers.

Definition at line 256 of file MCP23017Gpio.hxx.

dirty_

uint8_t MCP23017::dirty_ = 0

private

Bit mask of registers that need updating.

Definition at line 266 of file MCP23017Gpio.hxx.

executor_

ExecutorBase* MCP23017::executor_

private

Executor. We will be blocking this for the I2C IO.

Definition at line 249 of file MCP23017Gpio.hxx.

fd_

int MCP23017::fd_

private

I2C port file descriptor.

Definition at line 253 of file MCP23017Gpio.hxx.

gpio_

uint8_t MCP23017::gpio_[2]

private

Shadow of the input registers.

Definition at line 260 of file MCP23017Gpio.hxx.

i2cAddress_

uint8_t MCP23017::i2cAddress_

private

Address of this particular device on the I2C port.

Definition at line 263 of file MCP23017Gpio.hxx.

lat_

uint8_t MCP23017::lat_[2]

private

Shadow of the latch registers.

Definition at line 258 of file MCP23017Gpio.hxx.

POLLING_DELAY

constexpr long long MCP23017::POLLING_DELAY = MSEC_TO_NSEC(20)

staticconstexpr

Definition at line 50 of file MCP23017Gpio.hxx.

timer_

RefreshTimer MCP23017::timer_ {this}

private

Timer instance to schedule work on the executor.

Definition at line 251 of file MCP23017Gpio.hxx.

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

• MCP23017Gpio.hxx