#include <modm/architecture/interface/gpio_expander.hpp>

Inheritance diagram for modm::GpioExpanderPort< GpioExpander, expander, StartPin, Width, DataOrder >:

Public Types
enum	DataOrder : bool { DataOrder::Normal = false, DataOrder::Reversed = true }
	This enum can be used to reverse the bit order of the Data. More...

Static Public Member Functions
static constexpr DataOrder	getDataOrder ()

static void	setOutput ()

static void	setInput ()

static PortType	read ()

static void	write (PortType data)

static void	toggle ()

static void	write (PortType data)
	The write data is always right-aligned regardless of physical mapping.

Static Public Attributes
static constexpr uint8_t	width = Width

static constexpr GpioExpander &	ioExpander = expander

static constexpr uint8_t	number_of_ports

Detailed Description

template<typename GpioExpander, GpioExpander & expander, typename GpioExpander::Pin StartPin, uint8_t Width, GpioPort::DataOrder DataOrder = GpioPort::DataOrder::Normal>
class modm::GpioExpanderPort< GpioExpander, expander, StartPin, Width, DataOrder >

Create an modm::GpioPort compatible interface from any IO-expander conforming to the modm::GpioExpander interface.

This allows the transparent usage of IO Expander ports in classes that require Ports as template arguments. The port access is optimized so that only one write or one read needs to be performed to update the port values. Any port position and width is supported and operates independently from the other IOs on the expander.

Note: For every port access a blocking bus transfer is performed, therefore do not expect these ports to be fast!

Warning: You can also use SoftwareGpioPort to create a port out of individual GpioExpanderPin classes, however, since each pin is individually accessed, this means more bus traffic and a non-atomic write and read of port data! It is strongly recommended to use this optimized class instead!

Usage:

typedef modm::Pca8574<MyI2cMaster> Expander;
Expander expander;
 
typedef modm::GpioExpanderPort< Expander, expander, Expander::Pin::P4, 4 > Data;

However, instead of using this class like that, prefer using the alias-template types provided by the IO-expander of your choice for better readability:

typedef modm::Pca8574<MyI2cMaster> Expander;
Expander expander;
 
// a 4bit wide port in the upper nibble
typedef Expander::Port< expander, Expander::Pin::P4, 4 > Data;
 
// writes 0x50 on the port
Data::write(0x5);

You can reverse the ports bit order in software at runtime, so that data is written or read in reverse bit order when accessing the port:

// a 4bit wide port in the upper nibble with reversed bit order
typedef Expander::Port< expander, Expander::Pin::P4, 4, modm::GpioPort::DataOrder::Reversed > Data;
 
// writes 0xa0 on the port
Data::write(0x5);

Warning: Access to the IO-expander is blocking and can silently fail! If this is undesirable for you application, you need to write your own wrapper!

Precondition: The IO-expander needs to be initialized externally, if required.

See also: modm::GpioExpander; modm::GpioIO

Template Parameters

GpioExpander	Type of class conforming to the `modm::GpioExpander` interface
expander	instance of the expander with the selected pin
StartPin	starting pin of the port, physically LSB
Width	width of the entire port in bits
DataOrder	the bit order mapping of data

Author: Niklas Hauser

Member Enumeration Documentation

enum modm::GpioPort::DataOrder : bool

inheritedstrong

This enum can be used to reverse the bit order of the Data.

Enum Values	Documentation
Normal	bit order of data is the same as bit order of port
Reversed	bit order of data is the reverse bit order of port

Member Data Documentation

constexpr uint8_t modm::GpioPort::number_of_ports

inheritedstaticconstexpr

This holds the number of unique platform ports that this implementation accesses. It's always at least 1.

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

gpio_expander.hpp

Public Types

Static Public Member Functions

Static Public Attributes

Detailed Description

template<typename GpioExpander, GpioExpander & expander, typename GpioExpander::Pin StartPin, uint8_t Width, GpioPort::DataOrder DataOrder = GpioPort::DataOrder::Normal> class modm::GpioExpanderPort< GpioExpander, expander, StartPin, Width, DataOrder >

Member Enumeration Documentation

Member Data Documentation

template<typename GpioExpander, GpioExpander & expander, typename GpioExpander::Pin StartPin, uint8_t Width, GpioPort::DataOrder DataOrder = GpioPort::DataOrder::Normal>
class modm::GpioExpanderPort< GpioExpander, expander, StartPin, Width, DataOrder >