MCP23008 basic functions

Functions
bool	MCP::isBitValueHigh (uint8_t byteValue, uint8_t bitNumber)
	Checks if the Bit Value of a given bit position is high. More...
void	MCP::setClock (long freq)
	Sets I2C bus to a given frequency. More...
uint8_t	MCP::lookForDevice ()
	Look for MCP23008 device I2C Address. More...
void	MCP::reset ()
	Resets the MCP23008. More...
void	MCP::setup (uint8_t i2c=0x20, uint8_t io=GPIO_OUTPUT, int reset_pint=-1, long i2c_freq=100000)
	Starts the MCP23008. More...

Detailed Description

Function Documentation

isBitValueHigh()

bool MCP::isBitValueHigh ( uint8_t  byteValue, uint8_t  bitNumber  )

inline

Checks if the Bit Value of a given bit position is high.

This funcion is useful to extract a bit value (0 or 1) from a given MCP23008 register

Parameters

byteValue	byte or register value
bitNumber	bit offset (number / possition from 0 to 7)

Returns

true if the bit position is 1 (high)

setClock()

void MCP::setClock ( long  freq )

inline

Sets I2C bus to a given frequency.

100000 = 100KHz; 400000 = 400KHz etc

Plese check the property I2C bus frequency/speed of your board

Referenced by MCP::setup().

lookForDevice()

uint8_t MCP::lookForDevice

(

)

Look for MCP23008 device I2C Address.

This method will look for a valid MCP23008 device adress between 0x20 and 0x27

Returns

uint8_t the I2C address of the first MCP23008 device connect in the I2C bus

reset()

void MCP::reset

(

)

Resets the MCP23008.

this method can be used if you want to control the reset of the MCP23008 device. You need to select the Arduino pin via setup method.

You can used the MCP23008 RESET pin connected to the Arduino RESET pin. In this case, you not need to use this function.

See also

setup()

References MCP::reset_pin.

Referenced by MCP::setup().

setup()

void MCP::setup	(	uint8_t	i2c = 0x20,
		uint8_t	io = GPIO_OUTPUT,
		int	reset_pin = -1,
		long	i2c_bus_freq = 100000
	)

Starts the MCP23008.

Starts the MCP23008 and sets the default values.

Parameters

i2c	I2C address (0x20 ~ 0x27) - default 0x20; ports input / output setup; Arduino reset pin; and I2C clock frequency
io	If GPIO_OUTPUT (0), all GPIO PINS will configured to output If GPIO_INPUT (255), all GPIO PINS will configured to input You also can use a bitmask to configure some pins for input and other pins for output.
reset_pin	if you want to control the reset, select an Arduino pin to do that.
i2c_bus_freq	set the I2C bus frequency/speed (default 100000 = 100KHz)

References MCP::reset(), MCP::reset_pin, and MCP::setClock().