System and method for determining voltage levels

摘要

A method for determining a power source voltage level of a power source in a system in which the power source is connected to a microcontroller. A charging circuit is in direct communication with a pin of the microcontroller and the power source voltage level is determined by charging the charging circuit using a constant voltage level and determining a time when the charging circuit attains a voltage level sufficient to transition the pin of the microcontroller from a state corresponding to a logic "0" to a state corresponding to a logic "1." The determined time and a predetermined relationship between the power source voltage level and an input port transition voltage value of the microcontroller is then used to determine the power source voltage level of the power source.