System-on-a-chip integrated circuit including dual-function analog and digital inputs

1. An integrated circuit comprising:

a plurality of inputs;

a plurality of outputs;

a programmable logic block;

an analog circuit block coupled to at least one of the inputs, the analog circuit block including at least one hardwired analog function circuit;

an analog-to-digital converter programmably coupleable to individual analog circuits in the analog circuit block;

a digital circuit block coupled to at least one of the inputs, the digital circuit block including at least one hardwired digital function circuit;

an interconnect architecture programmably coupling selected ones of the plurality of inputs, the plurality of outputs, the programmable logic block, the analog circuit block, and the analog-to-digital converter;

wherein at least one of the inputs may be programmably configured as one of a digital input programmably coupleable to elements in the programmable logic block or as an analog input to an analog circuit in the analog circuit block.

2. The integrated circuit of claim 1 wherein the at least one of the inputs may be programmably configured as a digital input programmably coupleable to elements in the programmable logic block with a slew rate less than about 10MHz.

3. The integrated circuit of claim 1 wherein:

the at least one hardwired analog function circuit includes at least one of a digital-to-analog converter, an analog-to-digital converter, an analog pulse width modulator, a MOSFET controller, a voltage reference circuit, a low-dropout regulator, an analog multiplexer, and an RF transceiver; and

the at least one hardwired digital function circuit includes at least one of a state machine, analog sequencer, microprocessor, digital signal processor, and interface circuit.

4. The integrated circuit of claim 1 further including:

at least one operational amplifier in the at least one analog function circuit;

a programmable coupling circuit to selectively couple at least one of the inputs to the programmable logic block;

wherein the programmable coupling circuit interrupts power to the at least one operational amplifier when the coupling circuit is programmed to couple the at least one of the inputs to the programmable logic block.

5. The integrated circuit of claim 1 further including a clock system including a clock generator having multiple clock sources.

6. The integrated circuit of claim 1 wherein the multiple clock sources include a crystal oscillator and at least one RC oscillator.

7. The integrated circuit of claim 1 wherein the clock system includes at least one phase locked loop.

8. The integrated circuit of claim 1 wherein the at least one analog function circuit includes an analog-voltage pre-scaler circuit and the programmable coupling circuit includes a multiplexer having a first input coupled to the at least one of the inputs, a second input coupled to the at least one of the inputs through the analog-voltage pre-scaler circuit, and at least one programmable select input.

9. The integrated circuit of claim 1 wherein the coupling circuit includes at least one first MOS transistor coupled between a power rail and a power input on the at least one operational amplifier, and at least one second MOS transistor coupled between a power rail and a digital buffer coupled between the at least one of the inputs and the programmable logic block, the at least one first and second MOS transistors controlled by a decoder.

10. The integrated circuit of claim 9 wherein the decoder is driven by data on the at least one programmable select input of the multiplexer.

11. The integrated circuit of claim 1 wherein the coupling circuitry has a maximum digital bandwidth of less than about 10 MHz.