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235 lines
9.0 KiB
Markdown
235 lines
9.0 KiB
Markdown
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[](https://github.com/RobTillaart/AD5144A/actions/workflows/arduino-lint.yml)
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[](https://github.com/RobTillaart/AD5144A/blob/master/LICENSE)
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[](https://github.com/RobTillaart/AD5144A/releases)
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# AD5144A
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Arduino library for **I2C AD5144A** 4 channel digital potentiometer.
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Library has also classes for AD5123, AD5124, AD5143, AD5144, AD5144A, AD5122A, AD5142A, AD5121, AD5141
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## Description
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The library is an experimental library for the **I2C AD5144A** 4 channel digital potentiometer.
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- it is not tested extensively, (AD5144A partly)
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- so use at own risk, and
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- please report problems and/or success.
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From the datasheet it is expected that the library will work more or less
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for the family of related AD devices. However as said before this is not tested.
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If there are problems, please file an issue.
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This library uses the **I2C** interface to communicate with the device.
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It does not work for the **SPI** versions of these devices.
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See Future below.
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### Types supported
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| device | #potmeters | # rheostats | range | tested |
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|:--------|:-----------:|:-----------:|:------:|:-------:|
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| AD5123 | 2 | 2 | 0..127 | no |
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| AD5124 | 4 | 0 | 0..127 | no |
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| AD5143 | 2 | 2 | 0..255 | no |
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| AD5144 | 4 | 0 | 0..255 | partial |
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| AD5144A | 4 | 0 | 0..255 | partial |
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| AD5122A | 2 | 0 | 0..127 | no |
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| AD5142A | 2 | 0 | 0..255 | no |
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| AD5121 | 1 | 0 | 0..127 | no |
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| AD5141 | 1 | 0 | 0..255 | no |
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### Type AD51xy decomposition
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- x = 2 => range = 0..127
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- x = 4 => range = 0..255
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- y = 1 => 1 potentiometer
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- y = 2 => 2 potentiometers
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- y = 4 => 4 potentiometers
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- y = 3 => 2 potentiometers + 2 rheostats
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## I2C
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For the selection of the address, see table 12 / 13 datasheet.
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The AD5144A devices support standard 100 kHz, and fast 400 kHz, data transfer modes.
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## Interface
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The library has a number of functions which are all quite straightforward.
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As the library is experimental, function signatures might change in the future.
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### Constructor
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- **AD51XX(uint8_t address, TwoWire \*wire = &Wire)** base class, to set the I2C address and optional the Wire bus used.
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This class does not distinguish between the derived classes.
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The developer is responsible for handling these differences correctly when using the base class.
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#### Derived classes
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- **AD5123(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5124(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5143(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5144(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5144A(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5122A(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5142A(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5121(uint8_t address, TwoWire \*wire = &Wire)**
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- **AD5141(uint8_t address, TwoWire \*wire = &Wire)**
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### I2C / device initialization
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- **bool begin(int dataPin, int clockPin, bool doReset = true)** ESP32 a.o initializing of the I2C data and clock pins.
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If these pins are set to 255 (or above) the default pins will be used.
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If **doReset** == true (default) **reset()** is called, to load last values stored in EEPROM.
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Returns true if the address of the device can be found on the I2C bus.
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If the device cannot be found, **reset()** won't be called, even if **doReset** == true.
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- **bool begin(bool doReset = true)** for UNO, if **doReset** == true (default) **reset()** is called,
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to load last values stored in EEPROM.
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Returns true if the address of the device can be found on the I2C bus.
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If the device cannot be found, **reset()** won't be called, even if **doReset** == true.
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- **bool isConnected()** returns true if the address of the device can be found on the I2C bus, false otherwise.
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- **uint8_t reset()** calls the built in RESET command.
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This loads the last values stored in EEPROM in the RDAC's.
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Factory default is **midScale()** check datasheet for details.
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### Basic IO
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Used to set one channel at the time.
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- **uint8_t write(uint8_t rdac, uint8_t value)** set channel rdac 0..3 to value 0..255
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(depending on type less channels and lower max value should be used)
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The value is also written into a cache of last set values for fast retrieval later.
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If value > maxValue an error **AD51XXA_INVALID_VALUE** is returned.
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- **uint8_t read(uint8_t rdac)** read back set value from the **cache**, not from the device.
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### EEPROM
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The value stored in the EEPROM is the value the 4 potentiometers will start at boot time.
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This allows to start at predefined values and makes it possibly easier to continue after
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a reboot.
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- **uint8_t storeEEPROM(uint8_t rdac)** store the current channel value in EEPROM.
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- **uint8_t storeEEPROM(uint8_t rdac, uint8_t value)** store a specific (new) value in EEPROM.
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If value > maxValue an error **AD51XXA_INVALID_VALUE** is returned.
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- **uint8_t recallEEPROM(uint8_t rdac)** get the value from EEPROM and set the channel.
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Note: **reset()** resets all 4 channels from the last values stored in EEPROM.
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(Page 28 datasheet REV-C)
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### Asynchronous
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Sets values in sequence, not at exact same time
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- **uint8_t writeAll(uint8_t value)** write the same value to all channels.
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If value > maxValue an error **AD51XXA_INVALID_VALUE** is returned.
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- **uint8_t zeroAll()** sets all channels to 0.
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- **uint8_t midScaleAll()** sets all channels to their midpoint 128 / 64.
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- **uint8_t maxAll()** sets all channels to the max 255 / 127.
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- **uint8_t zero(uint8_t rdac)** sets one channel to 0.
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- **uint8_t midScale(uint8_t rdac)** sets one channel to its midpoint = 128 / 64.
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- **uint8_t maxValue(uint8_t rdac)** sets one channel to the max 255 / 127.
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### Synchronous
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- **uint8_t preload(uint8_t rdac, uint8_t value)** prepare a single rdac for a new value but only use it after **sync()** is called.
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If value > maxValue an error **AD51XXA_INVALID_VALUE** is returned.
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- **uint8_t preloadAll(uint8_t value)** prepare all rdacs with the same value, and wait for **sync()**.
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If value > maxValue an error **AD51XXA_INVALID_VALUE** is returned.
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- **uint8_t sync(uint8_t mask)** will transfer the preloaded values to the (4) rdacs at the very same moment.
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The 4-bit mask is used to select which rdacs to synchronize.
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### TopScale BottomScale
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See page 27 datasheet REV-C
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- **uint8_t setTopScale(uint8_t rdac)**
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- **uint8_t clrTopScale(uint8_t rdac)**
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- **uint8_t setTopScaleAll()**
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- **uint8_t clrTopScaleAll()**
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- **uint8_t setBottomScale(uint8_t rdac)**
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- **uint8_t clrBottomScale(uint8_t rdac)**
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- **uint8_t setBottomScaleAll()**
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- **uint8_t clrBottomScaleAll()**
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### Operational modes
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See page 27-28 datasheet REV-C
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- **uint8_t setLinearMode(uint8_t rdac)**
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- **uint8_t setPotentiometerMode(uint8_t rdac)**
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- **// 0 = potentiometer, 1 = linear
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- **uint8_t getOperationalMode(uint8_t rdac)**
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- **uint8_t incrementLinear(uint8_t rdac)**
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- **uint8_t incrementLinearAll()**
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- **uint8_t decrementLineair(uint8_t rdac)**
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- **uint8_t decrementLineairAll()**
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- **uint8_t increment6dB(uint8_t rdac)**
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- **uint8_t increment6dBAll()**
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- **uint8_t decrement6dB(uint8_t rdac)**
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- **uint8_t decrement6dBAll()**
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### ReadBack
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These function read back from the internal registers of the actual device.
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- **uint8_t readBackINPUT(uint8_t rdac)** reads back the "preload value" in the INPUT register.
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- **uint8_t readBackEEPROM(uint8_t rdac)** reads the **boot value** for the selected rdac from EEPROM.
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- **uint8_t readBackCONTROL(uint8_t rdac)** read back the control register.
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Read the datasheet for the details of the individual bits.
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- **uint8_t readBackRDAC(uint8_t rdac)** reads the value of the rdac from the device.
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### Write control register
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- **uint8_t writeControlRegister(uint8_t mask)** writes to the control register.
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Read the datasheet for the details of the individual bits.
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**Warning** use with care!
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### Misc
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- **uint8_t pmCount()** returns the number of potentiometers / channels the device has.
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Useful when writing your own loops over all channels.
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- **uint8_t maxValue()** return maxValue of the potentiometer. Values expected are 127 or 255.
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- **uint8_t shutDown()** check datasheet, not tested yet, use at own risk.
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## Operation
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The examples show the basic working of the functions.
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## Future
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**must**
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- update documentation
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- some functions can be performance optimized
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- writing a value is not needed if last value is the same?
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**could**
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- improve unit testing CI
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- more testing with hardware.
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- SPI based version of the library ?
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