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98 lines
3.6 KiB
Markdown
98 lines
3.6 KiB
Markdown
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[](https://github.com/marketplace/actions/arduino_ci)
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[](https://github.com/RobTillaart/TCA9548/actions/workflows/arduino-lint.yml)
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[](https://github.com/RobTillaart/TCA9548/actions/workflows/jsoncheck.yml)
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[](https://github.com/RobTillaart/TCA9548/blob/master/LICENSE)
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[](https://github.com/RobTillaart/TCA9548/releases)
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# TCA9548
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Arduino Library for TCA9548 I2C multiplexer.
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## Description
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Library for the TCA9548 and TCA9548a I2C multiplexer.
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The library allows you to enable 0 to 7 I2C channels (ports) uniquely or simultaneously.
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This is especially useful if you have multiple devices/sensors that have a fixed address,
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or you have address conflicts between I2C devices
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**Warning**
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The library is not tested extensively.
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I2C address is 0x70 .. 0x77.
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The library caches the channels enabled, and if a channel is enabled,
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it will not be enabled again (low level) to optimize performance.
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## Interface
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### Constructor
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- **TCA9548(const uint8_t deviceAddress, TwoWire \*wire = &Wire)** Constructor, address = 0x70 .. 0x77, wire = Wire or WireN.
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- **bool begin(uint8_t sda, uint8_t scl, uint8_t mask = 0x00)** Set I2C pins for ESP32, set mask of channels to be enabled.
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- **bool begin(uint8_t mask = 0x00)** set mask of channels to be enabled.
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- **bool isConnected()** returns true if address of the multiplexer is found on I2C bus.
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### Find device
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- **bool isConnected(uint8_t address)** returns true if arbitrary address is found on I2C bus.
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This can be used to verify a certain device is available (or not) on an enabled channel.
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### Channel functions
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- **void enableChannel(uint8_t channel)** enables channel 0 .. 7 non-exclusive.
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Multiple channels can be enabled in parallel.
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- **void disableChannel(uint8_t channel)** disables channel 0 .. 7.
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Will not disable other channels.
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- **void selectChannel(uint8_t channel)** enables a single channel 0 .. 7 exclusive.
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All other channels will be disabled in the same call, so not before or after.
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- **bool isEnabled(uint8_t channel)** returns true if the channel is enabled.
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- **void setChannelMask(uint8_t mask)** enables 0 or more channels simultaneously with a bit mask.
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- **uint8_t getChannelMask()** reads back the bit mask of the channels enabled.
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- **void setResetPin(uint8_t resetPin)** sets the pin to reset the chip. (Not tested)
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- **void reset()** trigger the reset pin.
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- **int getError()** returns the last I2C error.
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### Forced IO
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When forced IO is set all writes and read - **getChannelMask()** - will go to the device.
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If the flag is set to false it will cache the value of the channels enabled.
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This will result in more responsive / faster calls.
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Note that writes are only optimized if the channels are already set.
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- **void setForced(bool forced = false)** set forced write, slower but more robust.
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- forced == false == fast mode (default).
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- forced == true == robust mode.
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- **bool getForced()** returns set flag.
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## Operation
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See example
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## Future
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#### must
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- improve documentation.
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- improve error handling
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#### should
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- add examples
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- test test and test
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- write unit test
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- add **disableAll()** == setChannelMask(0)
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#### could
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- set an "always enabled" mask (have to investigate the consequences)
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- check PCA9548 compatibility
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