Programmable input/output circuit
AssigneeCypress Semiconductor Corporation
InventorsTimothy J. Williams, David G. Wright, Gregory J. Verge, Bruce E. Byrkett
Life of this patent
Estimating the term…
Abstract
A programmable input/output circuit includes a programmable output circuit configured to drive an output signal to an input/output pad at a plurality of voltages, at least one of the plurality of voltages being supplied by an external circuit. The programmable input/output circuit further includes a programmable input configured to detect an input signal from the input/output pad at the plurality of voltages. The voltage levels of the input and output circuits may be independently and dynamically controllable.
Claims20
An apparatus, comprising:
- a first input/output (I/O) pad;
- a second I/O pad;
- a programmable output circuit coupled to the first I/O pad and the second I/O pad, the programmable output circuit configurable to drive an output signal from a processing system to the first I/O pad at a plurality of voltages, wherein at least one of the plurality of voltages is based on a voltage supplied by an external circuit coupled to the apparatus, wherein the programmable output circuit comprises a programmable output buffer configured to receive a first programmable reference voltage signal as an output high level reference, wherein the first programmable reference voltage signal is received from the external circuit via the second I/O pad;
- and
- a programmable input circuit coupled to the I/O pad, the programmable input circuit configurable to detect an input signal to the processing system from the first I/O pad at the plurality of voltages.
A method, comprising:
- driving a programmable output signal from a processing system to a first input/output (I/O) pad at a plurality of voltages, wherein driving the programmable output signal to the first I/O pad comprises applying a first programmable reference voltage signal to a programmable output buffer as an output high level reference, wherein at least one of the plurality of voltages is based on a voltage supplied by an external circuit and the first programmable reference voltage signal is received from the external circuit via a second I/O pad;
- and
- detecting a programmable input signal to the processing system from the first I/O pad at the plurality of voltages generated by the processing system.
An apparatus, comprising:
- an input/output (I/O) pad;
- a programmable output circuit coupled to the I/O pad, the programmable output circuit comprising a first output buffer configured to operate at a first supply voltage and a second output buffer configured to operate at a second supply voltage, wherein a switching signal alternately enables either the first output buffer or the second output buffer, the programmable output circuit configurable to drive an output signal from a processing system to the I/O pad at a plurality of voltages, wherein at least one of the plurality of voltages is based on a voltage supplied by an external circuit coupled to the apparatus;
- and
- a programmable input circuit coupled to the I/O pad, the programmable input circuit configurable to detect an input signal to the processing system from the I/O pad at the plurality of voltages.
Dependencies are inferred from the claim text.