Patent ID: 7733119

Claim:
An integrated circuit comprising: a terminal for coupling to a resistor having a resistance value assigned to one of a plurality of different non-zero finite resistance values, wherein each different resistance value corresponds to a different operating mode of the integrated circuit and the different resistance values differ from each other based on a geometric progression of resistance values in accordance with the equation: Resistance=B K R 0 in which K is selected from the set K=0, 1, 2, . . . , 2 (N-1) −1, B is a numerical factor having a non-zero finite value and selected such that the value B K R 0 is finite R 0 is a selected base resistance having a non-zero finite value, and N is an integer value greater than 2; circuitry on the integrated circuit operable in the corresponding one of the modes in response to one of the resistance values presented by a resistor coupled to the terminal; circuitry measuring the resistance value of the resistor coupled to the terminal; based on the measured resistance value of the resistor, setting the integrated circuit into the corresponding one of the different operating modes; wherein the circuitry for measuring the resistance value of the resistor coupled to the terminal is operable to source current through the terminal when the resistor is coupled in series between the terminal and ground; and wherein the circuitry for measuring the resistance value of the resistor coupled to the terminal is operable to sink current through the terminal when the resistor is coupled in series between the terminal and a voltage supply.