TCA9548A Class Reference

API TCA9548A Multiplexer Breakout. More...

Detailed Description

• ID: TCA9548A
• Name: 1-to-8 I2C Multiplexer Breakout
• Category: multiplexer
• Manufacturer: adafruit
• Connection: i2c
• Link: https://learn.adafruit.com/adafruit-tca9548a-1-to-8-i2c-multiplexer-breakout/overview

The TCA9548A device has eight bidirectional translating switches that can be controlled through the I2C bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can be selected, determined by the contents of the programmable control register.

The TCA9548A Multiplexer Breakout enables to get - up to 8 same-address I2C devices hooked up to one microcontroller - or up to 8 independent I2C buses. This multiplexer acts as a gatekeeper, shuttling the commands to the selected set of I2C pins with your command. The TCA9548A multiplexer is interesting in that it has an I2C address (0x70 by default) - and you basically send it a command to tell it which I2C multiplexed output you want to talk to, then you can address the board you want to address. You simply write a single byte with the desired multiplexed output number to that port, and bam - any future I2C packets will get sent to that port.

The TCA9548A Multiplexer provides three pins (A0-A1-A2) that enable to change its address in case 0x70 address is used by another sensor on the same bus. By connecting one of the Ax pin to Vin you change its value from 0 to 1, these values change the value of the three first bits of the address :

Address 0b01110-A2-A1-A0 No wiring A2=0 A1=0 A0=0 Address 0b01110000 0x70 A0 wired A2=0 A1=0 A0=1 Address 0b01110000 0x71 A2 wired A2=1 A1=0 A0=0 Address 0b01110100 0x74 Any address between 0x70 and 0x77 can be selected.

Tested with Adafriut TCA9548A board.

Public Types
enum	TCA9548A_PORT_STATE { DISABLED = 0, ENABLED = 1 }
	boolean enum containing port state
enum	TCA9548A_PORT_MODE { EXCLUSIVE = 0, INCLUSIVE = 1 }
	boolean enum containing port access mode

Public Member Functions
	TCA9548A (int bus, uint8_t address=0x70)
	~TCA9548A ()
std::string	name ()
bool	getPort (int port)
void	setPort (int port, TCA9548A_PORT_STATE state, TCA9548A_PORT_MODE mode)
void	disableAllPorts ()
void	enableAllPorts ()

Constructor & Destructor Documentation

TCA9548A	(	int	bus,
		uint8_t	address = 0x70
	)

TCA9548A constructor

Parameters

address.

Device address. Default is 0x70.

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~TCA9548A

(

)

TCA9548A destructor

Member Function Documentation

std::string name ( )

inline

Returns the name of the switch

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bool getPort

(

int

port

)

Returns the status of a port as configured in the multiplexer.

Parameters

port	Switch port to check

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void setPort	(	int	port,
		TCA9548A_PORT_STATE	state,
		TCA9548A_PORT_MODE	mode
	)

Configure an individual port on the multiplexer

Parameters

port	Port to configure
enabled	Set to true to enable the port, false to disable the port.
exclusive	Set to true to disable all other ports, false to leave existing port config untouched. When exclusive is set to false, an additional i2c read is required to read the current port setting.

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void disableAllPorts

(

)

Disables all ports on the multiplexer.

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void enableAllPorts

(

)

Enables all ports on the multiplexer. Useful when the multiplexer is used to electrically extend the bus rather than resolve address conflicts.

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

• src/tca9548a/tca9548a.hpp
• src/tca9548a/tca9548a.cxx