Component: IO Expander (PCF8574) (Comms: System)

Author	Matrix TSL
Version	1.0
Category	Comms: System

IO Expander component

Provides 8 digital input/output pins arranged into an 8-bit port using a I2C bus connection. Up to eight expanders can be connected to the same I2C peripheral by means of three address pins. Supports the PCF8574 and PCF8574A devices allowing up to 16 expanders to be connected to the same I2C bus ( 8 x PCF8574 + 8 x PCF8574A ).

Detailed description

No detailed description exists yet for this component

Examples

No additional examples

Downloadable macro reference

	ReadPort
Reads the value of the IO pins.
- BYTE	Return

	WritePort
Writes a value to the IO pins.
- BYTE	Value
Value to write. Range 0-255
- VOID	Return

	Initialise
- VOID	Return

	Initialise
Enables the I²C hardware and performs some initialization. Should be called at the start of the program or at least before any of the other I²C functions are called.
- VOID	Return

	Initialise
Startup the I2C bus ready for communications.
- VOID	Return

	Transaction_Read
Attempt to read Length number of bytes from the I2C slave to the given Buffer. Ensure that the Buffer is large enough. Returns number of bytes read, caller should check that this matches requested Length
- BYTE	Buffer
Buffer to store the incoming byte data
- UINT	Length
Number of bytes to read
- UINT	Return

	Start
Outputs a start condition onto the I²C bus.
- VOID	Return

	Transaction_Initialise
Initialise the I2C interface to communicate with a Slave device at Address Returns 0 on fail, 1 on success
- BYTE	Address
7-bit I2C Address without the shift for the R/W bit
- BYTE	Return

	Initialise
Enables the I²C hardware and performs some initialization. Should be called at the start of the program or at least before any of the other I²C functions are called.
- VOID	Return

	Initialise
Initialise the sensor configuration as set by the component properties. Sets the default intigration time and gain as well as enable the sensor.
- VOID	Return

Property reference

	Properties
	Device Type
	External Address
Selects the value of the three address pins for the MCP23S17.
	Channel
Channel selection
	Stop Delay
On older microcontroller devices there is a potential for the I2C hardware channel to lock up if there is not a 10ms delay between an I2C stop event and the next I2C start event. Most modern microcontrollers will not have a problem so this property can be disabled to speed up the I2C communications.
	Baud Select
Baud rate option selector
	Baud Rate
Baud rate to be used
	SDA
Pin used for SDA (data signal)
	SCL
Pin used for SCL (clock signal)
	Connections
	Simulations
	Label
	Scope Traces
Selects if the scope traces are automatically generated or not
	Console Data
Selects if the console data is automatically generated or not
	API