DIGI POT 11 Click is a compact add-on board representing a digitally controlled potentiometer. This board features a double pack of the MAX5387, a dual, 256-tap, volatile, low-voltage linear taper digital potentiometer from Analog Devices. This way, four digitally I2C-controlled potentiometers are realized with end-to-end resistance values of 50kΩ. Operating from a single +3.3V power supply, this device provides a low 35ppm/ºC end-to-end temperature coefficient. This Click board™ can be used as a mechanical potentiometer replacement for the portable consumer market and battery-backup industrial applications.
DIGI POT 11 Click as its foundation uses a double pack of the MAX5387, a dual volatile, low-voltage linear taper digital potentiometer from Analog Devices, with which four digitally controlled potentiometers are realized with end-to-end resistance values of 50kΩ. The potentiometers consist of 255 fixed resistors in series between appropriate H and L terminals, providing a low 35ppm/ºC end-to-end temperature coefficient. The potentiometer wiper (W) terminals are programmable to access any one of the 256 tap points on the resistor string.
This Click board™ communicates with MCU using the standard I2C 2-Wire interface with a maximum clock frequency of 400kHz. The potentiometers are programmable independently of each other. The MAX5387 has a 7-bit peripheral address with the first five MSBs fixed to 01010. The address pins A0 and A1 of both potentiometers are programmed by the user and determine the value of the last three LSBs of the peripheral address, which can be selected by positioning onboard SMD jumpers labeled as ADDR SEL, in U1 or U2 part, to an appropriate position marked as 0 or 1.
The I2C interface contains a shift register that decodes the command and addresses bytes, routing the data to the appropriate control registers. Data written to a control register immediately updates the wiper position. In the beginning, wipers A and B always power up in mid-position.
This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.
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