Patent ID: 7366577

Claim:
A programmable analog input/output (I/O) integrated circuit (IC) system comprises: a plurality of IC pins: an analog I/O circuit operably coupled to the plurality of pins, wherein the analog I/O circuit determines input/output status of each of the plurality of IC pins, wherein the analog I/O circuit includes: a plurality of I/O modules operably coupled to and corresponding to the plurality of IC pins, wherein an I/O module of the plurality of I/O modules includes at one of: an input buffer operably coupled to a corresponding one of the plurality of IC pins, wherein, when the I/O control signal is in a first state, the input buffer is active; a tri-state output buffer operably coupled to the corresponding one of the plurality of IC pins, wherein, when the I/O control signal is in a second state, the tri-state output buffer is active; and sensing module operably coupled to the corresponding one of the plurality of IC pins, wherein the sensing module senses the I/O status of the corresponding one of the plurality of IC pins, wherein the sensing module includes: load impedance module operably coupled to determine impedance of a load coupled to the corresponding one of the plurality of IC pins, wherein the load impedance module includes: load current source operably coupled to source a current to the load to produce a load voltage; reference current source operably coupled to source a controlled current to a reference impedance to produce a reference voltage; comparator operably coupled to compare the reference voltage to the load voltage; and control logic operably coupled to interpret an output of the comparator, wherein, when the output of the comparator is in a first state, the control logic adjusts the reference impedance to produce a second reference voltage, and when the output of the comparator is in a second state, the control logic enables storing the impedance of the load based on the reference impedance; and determination module operably coupled to determine a type of load coupled to the corresponding one of the plurality of IC pins based on the impedance of the load; control module operably coupled to the analog I/O circuit to provide an I/O control signal to the analog I/O circuit based on the I/O status of each of the plurality of IC pins and to provide a switching control signal for configuring the programmable analog I/O IC system; and switching module operably coupled to the analog I/O circuit based on the switching control signal.