Demand Peripherals             Robotics and Automation Made Easy

  

DPOT: Dual Digital Potentiometer

When used with the DPOT card, the dual digital potentiometer gives you control of two 50K Ohm digital potentiometers.

 

Hardware:

The DPOT peripheral must be paired with DPOT card.

The DPOT peripheral controls a Microchip MCP4251 dual 50K pot. It has a 257 steps from 0 to 50K Ohms and has a wiper resistance of 75 Ohms. The DPOT card uses the ESPI 7474 circuit for reliable operation.

 

Resources:

The dual digital potentiometer offers a configurable minimum and maximum resistance which makes it easier to replace the 50K part with a part that has a different maximum resistance.

resistance : The potentiometer resistance between the A terminal and the wiper as two unsigned decimal numbers separated by a space and terminated by a newline. Resistances outside of the min-max range are set to the minimum or maximum as appropriate. The setting are mapped to the closest resistance possible with 257 steps. The actual resistance might not match the exact value you specify. Reading the resistance resource gives one of the 257 possible values the part can achieve.

min-max : The minimum and maximum resistance as two unsigned decimal numbers separated by a space and terminated by a newline. The default values for min-max are 75 and 50075. This is a read-write resource.

 

Examples:

Set Pot0 to 10K and Pot1 to 20K.

   dpset dpot resistance 10000 20000 

What are the actual values for the command above?

   dpget dpot resistance