Patent ID: 8466817

Claim:
An electronic device, comprising: a processor, comprising: a first multi-purpose pin; a second multi-purpose pin; an external device connection port for connecting to an external device, wherein the external device connection port is connected to the first multi-purpose pin and is at a tested voltage that is to be measured; a first resistance element, having a first terminal connected to the external device connection port and having a second terminal connected to a high level voltage; and a second resistance element, having a first terminal connected to the external device connection port and having a second terminal connected to the second multi-purpose pin, wherein, the processor is configured to: output one of the high level voltage and a low level voltage via the second multi-purpose pin when the tested voltage is in a nonlinear operating region of a function block of the processor, to guarantee the tested voltage in a linear region of the function block, wherein, the function block is coupled to the first multi-purpose pin via a multiplexing design.