Intel Corporation

Bradley G Heaney

Waleed S Almulla

Meeling Roberts

Jehanbux J Edulbehram

Gloria Leong

Ronald J Mayer

An apparatus having a 3.3 volt power supply and a 5 volt power supply, wherein digital signals are processed on a 3.3 volt basis which are translated to a 5 volt basis by a voltage translation circuit before being output. The voltage translator is comprised of an inverter for inverting an input signal. The inverter is powered by the 3.3 volt power supply. A p-channel transistor having its source coupled to the 5 volt power supply and its gate driven by the output of the inverter is implemented. When the inverter generates a low logic, the p-channel transistor is turned on and outputs 5 volts. An n-channel transistor having its source coupled to ground and its gate driven by the output of the inverter is also implemented. When the output of the inverter is 3.3 volts, the n-channel transistor is turned on, which pulls the output to ground. Therefore, when the input signal is at 3.3 volts, a 5 volt signal is output from the voltage translation circuit. When the input signal is at 0 volts, the output signal is, likewise, at 0 volts.

Apparatus for translating logic signal levels from 3.3 volts to 5 volts

An input to the control unit of a microprocessor places the microprocessor in a WAIT condition whenever the input clock frequency is determined to be greater than a predetermined maximum value. An RC circuit in combination with a Schmitt trigger generates a 'kill signal' whenever the time interval between successive clock pulses is less than a value corresponding to a cut-off frequency. To assure that the microprocessor is not placed in a WAIT state by an occasional 'glitch' on the clock input, the kill signal applied to the microprocessor control unit is provided from a four-bit counter. If the Schmitt trigger generates a kill signal on eight consecutive clock cycles, the counter output changes state and sequencing of microcode by the control unit is suspended.

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Mountain View, CA, United States of America

Bradley G Heaney