Author Topic: I2C Digital Potentiometer on PIRA32  (Read 2866 times)

superjr83

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I2C Digital Potentiometer on PIRA32
« on: December 09, 2014, 03:36:56 pm »
Hello ...

Someone already used the digital potentiometer via I2C to control the RDS level?
I have an automated application that uses the PIRA32 and I would like to implement an Automatic Gain Control.

What I2C device should I use? It has some to indicate?


Best Regards
Fernando Santos :D / Brazil

Jan

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Re: I2C Digital Potentiometer on PIRA32
« Reply #1 on: December 10, 2014, 03:22:04 pm »
Optional digital output level control is based on Microchip MCP4551-103 (see the figure 1). Once the MCP4551 is connected to the bus, it is recognized automatically by the PIRA32 on reset or power-up. The output level can be controlled by the ASCII command LEVEL.

For implementation in the standard PIRA32 board/schematic (i.e. with mechanical trimmer), the output of the MCP4551 must include voltage follower (see the image 2). The best place for the installation is between C15 and R12 in existing schematic diagram. The MCP4551 is supplied from +5V, the voltage follower opamp is supplied from the U analog (UA), like existing opamps.

Take note that unlike mechanical trimmers, the digital potentiometer does not accept voltage outside the Vss-Vdd range on any pin.

superjr83

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Re: I2C Digital Potentiometer on PIRA32
« Reply #2 on: December 11, 2014, 07:11:25 pm »
Thank you Jan ... I'll make implementations.

Best Regards,
Fernando.