GY-63_MS5611/libraries/TCA9548

TCA9548

Arduino Library for TCA9548 I2C multiplexer.

Description

Library for the TCA9548 and TCA9548a (PCA9548, PCA9548a) I2C multiplexer.

The library allows you to enable 0 to 7 I2C channels (ports) uniquely or simultaneously. This is especially useful if you have multiple devices/sensors that have a fixed address, or you have address conflicts between I2C devices

Warning The library is not tested extensively.

I2C address of the device itself is 0x70 .. 0x77. This address may not be used on any of the I2C channels of course.

The library caches the channels enabled, and if a channel is enabled, it will not be enabled again (low level) to optimize performance.

0.2.0 Breaking change

Version 0.2.0 introduced a breaking change. You cannot set the pins in begin() any more. This reduces the dependency of processor dependent Wire implementations. The user has to call Wire.begin() and can optionally set the Wire pins before calling begin().

Compatible devices

This library is expected to work for the PCA9548(a) too as the TCA is pin compatible newer version.

Device	Tested	Notes
TCA9548s	n
PCA9548	n	see links below
PCA9548a	n

There are however small differences, check the data sheets to see the details.

• difference TCA PCA
• https://electronics.stackexchange.com/questions/209616/is-nxps-pca9548a-compatible-with-tis-tca9548a
• https://www.nxp.com/docs/en/application-note/AN262.pdf

Related

• https://github.com/RobTillaart/HC4051 (1x8 mux)
• https://github.com/RobTillaart/HC4052 (2x4 mux)
• https://github.com/RobTillaart/HC4053 (3x2 mux)
• https://github.com/RobTillaart/HC4067 (1x16 mux)

Interface

#include "TCA9548.h"

Constructor

• TCA9548(const uint8_t deviceAddress, TwoWire *wire = &Wire) Constructor. deviceAddress = 0x70 .. 0x77, wire = Wire or WireN.
• bool begin(uint8_t dataPin, uint8_t clockPin, uint8_t mask = 0x00) Set I2C pins for ESP32. Set mask of channels to be enabled, default all disabled.
• bool begin(uint8_t mask = 0x00) set mask of channels to be enabled, default all disabled.
• bool isConnected() returns true if address of the multiplexer is found on I2C bus.

The derived class PCA9548 has same interface, except constructor.

• PCA9548(const uint8_t deviceAddress, TwoWire *wire = &Wire) Constructor. deviceAddress = 0x70 .. 0x77, wire = Wire or WireN.

Find device

• bool isConnected(uint8_t address) returns true if arbitrary address is found on I2C bus. This can be used to verify a certain device is available (or not) on an enabled channel.

Channel functions

All "channel functions" return true on success.

• bool enableChannel(uint8_t channel) enables channel 0 .. 7 non-exclusive. Multiple channels can be enabled in parallel.
• bool disableChannel(uint8_t channel) disables channel 0 .. 7. Will not disable other channels.
• bool selectChannel(uint8_t channel) enables a single channel 0 .. 7 exclusive. All other channels will be disabled in the same call, so not before or after.
• bool isEnabled(uint8_t channel) returns true if the channel is enabled.
• bool disableAllChannels() fast way to disable all.
• bool setChannelMask(uint8_t mask) enables 0 or more channels simultaneously with a bit mask.
• uint8_t getChannelMask() reads back the bit mask of the channels enabled.

Reset

• void setResetPin(uint8_t resetPin) sets the pin to reset the chip. (Not tested)
• void reset() trigger the reset pin.
• int getError() returns the last I2C error.

Forced IO

When forced IO is set all writes and read - getChannelMask() - will go to the device. If the flag is set to false it will cache the value of the channels enabled. This will result in more responsive / faster calls. Note that writes are only optimized if the channels are already set.

• void setForced(bool forced = false) set forced write, slower but more robust.
  • forced == false == fast mode (default).
  • forced == true == slower, robust mode.
• bool getForced() returns set flag.

Error Codes

Not implemented yet, preparation for 0.2.0.

name	value	description
TCA9548_OK	00	no error
TCA9548_ERROR_I2C	-10	detected an I2C error
TCA9548_ERROR_CHANNEL	-20	channel out of range

Future

PCA954X family

To investigate if these can be made in one derived class tree.

chip	address	channel	interrupt	reset	notes
PCA9540	-	2			address programmable
PCA9641	4 pins	2			master selector
PCA9542	3 pins	2	Y
PCA9543	2 pins	2	Y	Y
PCA9544	3 pins	4	Y
PCA9545	2 pins	4	Y	Y
PCA9546	3 pins	4		Y
PCA9548	3 pins	8		Y	equals TCA9648

• Most could work if a "channels" was defined and if internals are enough similar.
• RESET pin is supported in TCA9548
• INT is more a user code issue.
• might need a type()?

Must

• improve documentation.
• improve error handling.

Should

• add examples.
• test test and test.
• write unit test.
• create derived classes for compatible devices (0.2.0).
  • see above PCA9548 and PCA9548a.
• investigate support derived classes

Could

• set an "always enabled" mask.
  • investigate the consequences!

Wont

Support

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Thank you,