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GY-63_MS5611/libraries/TCA9548/README.md
rob tillaart d0045e9601 0.1.3 TCA9548
2022-11-26 13:02:08 +01:00

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Arduino CI Arduino-lint JSON check License: MIT GitHub release

TCA9548

Arduino Library for TCA9548 I2C multiplexer.

Description

Library for the TCA9548 and TCA9548a 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 is 0x70 .. 0x77.

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

Interface

Constructor

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

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

  • void enableChannel(uint8_t channel) enables channel 0 .. 7 non-exclusive. Multiple channels can be enabled in parallel.
  • void disableChannel(uint8_t channel) disables channel 0 .. 7. Will not disable other channels.
  • void 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.
  • void 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.
  • 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 == robust mode.
  • bool getForced() returns set flag.

Operation

See example

Future

must

  • improve documentation.
  • improve error handling

should

  • add examples
  • test test and test
  • write unit test
  • add disableAll() == setChannelMask(0)

could

  • set an "always enabled" mask (have to investigate the consequences)
  • check PCA9548 compatibility