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MCP23008 Class Reference

#include <MCP23008.hh>

Inheritance diagram for MCP23008:
Inheritance graph
Collaboration diagram for MCP23008:
Collaboration graph

Public Types

enum  InterruptMode { DISABLE = 0, ON_CHANGE = 1, ON_FALLING = 2, ON_RISING = 3 }
 

Public Member Functions

 MCP23008 (uint8_t subaddr=0)
 
bool begin ()
 
bool data_direction (uint8_t iodir)
 
bool pullup (uint8_t gppu)
 
bool input_pin (uint8_t pin)
 
bool pullup_pin (uint8_t pin)
 
bool interrupt_pin (uint8_t pin, InterruptMode mode)
 
bool output_pin (uint8_t pin)
 
bool read_pin (uint8_t pin)
 
bool write_pin (uint8_t pin, uint8_t value)
 
uint8_t read ()
 
bool read (void *buf, size_t size)
 
bool write (uint8_t value)
 
bool write (void *buf, size_t size)
 

Protected Types

enum  {
  IODIR = 0x00, IPOL = 0x01, GPINTEN = 0x02, DEFVAL = 0x03,
  INTCON = 0x04, IOCON = 0x05, GPPU = 0x06, INTF = 0x07,
  INTCAP = 0x08, GPIO = 0x09, OLAT = 0x0a, REG_MAX = 0x0b
}
 
enum  {
  INTPOL = 1, ODR = 2, HAEN = 3, DISSLW = 4,
  SEQOP = 5
}
 

Protected Attributes

uint8_t m_iodir
 
uint8_t m_gpinten
 
uint8_t m_defval
 
uint8_t m_intcon
 
uint8_t m_gppu
 
uint8_t m_olat
 
uint8_t m_reg
 

Static Protected Attributes

static const uint8_t SUBADDR_MASK = 0x07
 
static const uint8_t PIN_MASK = 0x07
 

Private Member Functions

bool is_async () const
 
void sync_request ()
 
void async_request ()
 
virtual void on_completion (uint8_t type, int count)
 

Private Attributes

uint8_t m_addr
 
bool m_async
 

Detailed Description

Driver for the MCP23008 8-bit I/O Expander with I2C Interface and Interrupt.

Circuit

MCP23008
+------------+
(SCL)---------------1-|SCL VCC|-18--------------(VCC)
(SDA)---------------2-|SDA GP7|-17---------------(P7)
(A2)----[ ]---------3-|A2 GP6|-16---------------(P6)
(A1)----[ ]---------4-|A1 GP5|-15---------------(P5)
(A0)----[ ]---------5-|A0 GP4|-14---------------(P4)
(RST)---------------6-|RESET/ GP3|-13---------------(P3)
7-|NC GP2|-12---------------(P2)
(EXT)---------------8-|INT GP1|-11---------------(P1)
(GND)---------------9-|GND GP0|-10---------------(P0)
+------------+

References

  1. Microchip Technology Inc., Device Documentation, DS21919E, 2007. http://ww1.microchip.com/downloads/en/DeviceDoc/21919e.pdf

Definition at line 50 of file MCP23008.hh.

Member Enumeration Documentation

anonymous enum
protected

Register Addresses, table 1-2, pp. 6.

Enumerator
IODIR 

I/O Direction Register.

IPOL 

Input Polarity Register.

GPINTEN 

Interrupt on Change Control Register.

DEFVAL 

Default Compare Register.

INTCON 

Interrupt Control Register.

IOCON 

Configuration Register.

GPPU 

Pull-up Resistor Configuration.

INTF 

Interrupt Flag Register.

INTCAP 

Interrupt Capture Register.

GPIO 

Port Register.

OLAT 

Output Latch Register.

REG_MAX 

Number of Registers.

Definition at line 209 of file MCP23008.hh.

anonymous enum
protected

Configuration Register Bits, pp. 15.

Enumerator
INTPOL 

Polarity of Interrupt Pin.

ODR 

Open-drain Output enable.

HAEN 

Hardware Address Enable (SPI).

DISSLW 

Slew Rate disable.

SEQOP 

Sequence Operation mode disable.

Definition at line 225 of file MCP23008.hh.

enum MCP23008::InterruptMode

Interrupt Pin modes

Enumerator
DISABLE 

Interrupt disabled.

ON_CHANGE 

Interrupt on change (toggle).

ON_FALLING 

Interrupt on falling (high to low).

ON_RISING 

Interrupt on rising (low to high).

Definition at line 53 of file MCP23008.hh.

Constructor & Destructor Documentation

MCP23008::MCP23008 ( uint8_t  subaddr = 0)
inline

Construct connection to MCP23008 8-bit I/O Expander with given sub-address. All pins are input on reset. Interrupt disabled.

Parameters
[in]subaddrsub-address (0..7, default 0).

Definition at line 65 of file MCP23008.hh.

Member Function Documentation

bool MCP23008::begin ( )

Initiate device driver. Return true if initiated otherwise false.

Returns
bool.

Definition at line 24 of file MCP23008.cpp.

bool MCP23008::data_direction ( uint8_t  iodir)

Set data direction for port pin P0..P7; 0 for output, 1 for input. Return true if set otherwise false.

Parameters
[in]iodirdata direction mask.
Returns
bool.

Definition at line 47 of file MCP23008.cpp.

bool MCP23008::input_pin ( uint8_t  pin)
inline

Set given pin as input. Return true if set otherwise false.

Parameters
[in]pinnumber (0..7).
Returns
bool.

Definition at line 102 of file MCP23008.hh.

bool MCP23008::interrupt_pin ( uint8_t  pin,
InterruptMode  mode 
)

Set interrupt mode for given pin. Return true if set otherwise false.

Parameters
[in]pinnumber (0..7).
[in]modeinterrupt.
Returns
bool.

Definition at line 69 of file MCP23008.cpp.

bool MCP23008::output_pin ( uint8_t  pin)
inline

Set given pin as output. Return true if set otherwise false.

Parameters
[in]pinnumber (0..7).
Returns
bool.

Definition at line 133 of file MCP23008.hh.

bool MCP23008::pullup ( uint8_t  gppu)

Set pullup mode for port pin P0..P7; 0 for normal, 1 for pullup resistor. Return true if set otherwise false.

Parameters
[in]gppupullup resistor mask.
Returns
bool.

Definition at line 58 of file MCP23008.cpp.

bool MCP23008::pullup_pin ( uint8_t  pin)
inline

Set given pin pullup. Return true if set otherwise false.

Parameters
[in]pinnumber (0..7).
Returns
bool.

Definition at line 113 of file MCP23008.hh.

uint8_t MCP23008::read ( )

Read pins and return current values.

Returns
input pin values.

Definition at line 110 of file MCP23008.cpp.

bool MCP23008::read ( void *  buf,
size_t  size 
)

Read pins value into given buffer with given size. Return true if successful otherwise false.

Parameters
[in,out]bufpointer to buffer for data.
[in]sizenumber of bytes to read.
Returns
bool.

Definition at line 124 of file MCP23008.cpp.

bool MCP23008::read_pin ( uint8_t  pin)
inline

Read given pin and return true is set otherwise false.

Parameters
[in]pinnumber (0..7).
Returns
bool.

Definition at line 144 of file MCP23008.hh.

bool MCP23008::write ( uint8_t  value)

Write given value to the output pins. Return true if successful otherwise false.

Parameters
[in]value.
Returns
bool.

Definition at line 139 of file MCP23008.cpp.

bool MCP23008::write ( void *  buf,
size_t  size 
)

Write given values to the output pins. Allow sequence of updates to output pins in a single write. Return true if successful otherwise false.

Parameters
[in]bufpointer to data to write to port.
[in]sizeof buffer.
Returns
bool.

Definition at line 150 of file MCP23008.cpp.

bool MCP23008::write_pin ( uint8_t  pin,
uint8_t  value 
)
inline

Write set given output pin if value is non-zero, otherwise clear. Return true if successful otherwise false.

Parameters
[in]pinnumber (0..7).
[in]value.
Returns
bool.

Definition at line 157 of file MCP23008.hh.

Member Data Documentation

uint8_t MCP23008::m_defval
protected

Default Compare Register, 0 = rising, 1 = falling.

Definition at line 240 of file MCP23008.hh.

uint8_t MCP23008::m_gpinten
protected

Interrupt on Change Control Register, 0 = disable, 1 = enable.

Definition at line 237 of file MCP23008.hh.

uint8_t MCP23008::m_gppu
protected

Pullup Register, 0 = disable, 1 = pullup enable, default disable.

Definition at line 246 of file MCP23008.hh.

uint8_t MCP23008::m_intcon
protected

Interrupt Control Register, 0 = change/toggle, 1 = compare.

Definition at line 243 of file MCP23008.hh.

uint8_t MCP23008::m_iodir
protected

Data Direction Register, 0 = output, 1 = input, default all input.

Definition at line 234 of file MCP23008.hh.

uint8_t MCP23008::m_olat
protected

Output Register values.

Definition at line 249 of file MCP23008.hh.

uint8_t MCP23008::m_reg
protected

Current Register.

Definition at line 252 of file MCP23008.hh.

const uint8_t MCP23008::PIN_MASK = 0x07
staticprotected

Pin number mask.

Definition at line 206 of file MCP23008.hh.

const uint8_t MCP23008::SUBADDR_MASK = 0x07
staticprotected

Sub-address mask.

Definition at line 203 of file MCP23008.hh.

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