A system which includes a microprocessor (or microcontroller) and an auxiliary chip which monitors the system power supply voltage and performs related functions for the microprocessor. Another of the innovative teachings set forth in the present application is that the microprocessor can access the auxiliary chip to ascertain the power history. That is, the microprocessor can direct an interrupt to the auxiliary chip, which will cause the auxiliary chip to respond with a signal which indicates to the microprocessor whether the power supply voltage is heading up or down. When the microprocessor is reset at power-up, and detects that the power supply voltage is still marginal, the present invention permits the microprocessor to determine (by querying the auxiliary chip) whether the supply voltage is marginal so that the microprocessor does not go into full operation until the supply voltage is high enough.