I am using MCP4131 with 7 - bit ( 0 - 127 ). Datasheet said that, it can work bit 7 and 8 bit and i definetly need to use it with 8 bit ( 0 - 255 ). Here is my code below; #include <SPI.h> byte address = 0x00; int CS= 10; void setup() { pinMode (CS, OUTPUT); SPI.begin(); } void loop() { digitalPotWrite(50); } int digitalPotWrite(int value) { digitalWrite(CS, LOW); SPI.transfer(address); SPI.transfer(value); digitalWrite(CS, HIGH); } This is 7 bit code, to make it 8 bit, What should i change in the code ? Or what i need to do ? Thank You Best Regards