MCP41xxx digital potentiometer

   I have one MCP41010 digital potentiometer with 10kohms value in 256 steps (0 to 255 steps = 8 bits) who can controllled by a microcontroler or development board thru SPI conenctor.

   I search info about this digital potentiometer and I noted 2 usefull articles:

- Single/Dual digital Potentiometer (MCP41xxx, MCP42xxx) from www.arduino-projekte.de

- MCP41010 Digital Potentiometer Arduino User Manual from Henry's bench

   I use Arduino Mega board in this schematic:

am I use MCP41xxx_lcd1602_i2c_test.ino sketch.

   After I read the datasheet I realised this digital potetiometer has a "wiper ressitance". Tipical value for 5V is 52 ohms (maximum 100 ohms).

   In tests, I can see:

- minimum value (step no. 0):

- maximum value (step no. 255):

If I change potentiometer at 3.3V, I can see:

- minimum value (step no. 0):

- maximum value (step no. 255):

   You can see test with MCP41010 digital potentiometer and Arduino Mega (2) movie for understund more clear what i write: