pyupm_tca9548a module

class pyupm_tca9548a.TCA9548A(bus, address=112)

Bases: object

API TCA9548A Multiplexer Breakout.

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.

C++ includes: tca9548a.hpp

DISABLED = 0

ENABLED = 1

EXCLUSIVE = 0

INCLUSIVE = 1

disableAllPorts()

void disableAllPorts()

Disables all ports on the multiplexer.

enableAllPorts()

void enableAllPorts()

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

getPort(port)

bool getPort(int port)

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

port: Switch port to check

name()

std::string name()

Returns the name of the switch

setPort(port, state, mode)

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

Configure an individual port on the multiplexer

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.