IC with digital and analog circuits and mixed signal I/O pins

• US 6,509,758 B2
• Filed: 04/18/2001
• Issued: 01/21/2003
• Est. Priority Date: 04/18/2001
• Status: Expired due to Term

• Current Assignee: Silicon Labs CP, Inc. (Silicon Laboratories Incorporated)
• Original Assignee: Cygnal Integrated Products, Inc. (Silicon Laboratories Incorporated)
• Inventors: Piasecki, Douglas S., Storvik, Alvin C. II
• Primary Examiner(s): Tokar, Michael
• Assistant Examiner(s): Tran, Anh Q.
• Application Number:
  US09/837,921
• Publication Number:
  US 20020153923A1
• Time in Patent Office: 643 Days
• Field of Search: 326/37-41
• US Class Current: 326/37
• CPC Class Codes: G06J 1/00 Hybrid computing arrangements digitally-programmed analogue computers G06G7/06

Abstract

An integrated circuit providing mixed signal processing. I/O pin interface circuits include logic gates and other circuits for processing digital and analog signals. Processor-controlled configuration circuits allow the various I/O pin interface circuits to process either analog or digital circuits. The I/O pins can be configured for digital or analog operation on the fly.

Claims

1. An integrated circuit having I/O pin interface circuits providing digital and analog functions, comprising:

digital circuits and at least one analog circuit formed on said integrated circuit;

a plurality of contact pads formed on said integrated circuit;

a multiplexer circuit;

a plurality of I/O pin interface circuits, each I/O pin interface circuits associated with a respective said contact pad, each said I/O pin interface circuit coupling digital signals between the respective contact pads and said digital circuits, at least some of said I/O pin interfaces coupling analog signals between said contact pads and said multiplexer circuit; and

said multiplexer circuit coupled between said I/O pin interface circuits and said analog circuit for selectively coupling signals between said analog circuit and said I/O pin interface circuits.

2. The integrated circuit of claim 1, further including an analog line coupled to each said pin interface, and an analog transmission gate for controlling coupling of analog signals on said analog lines.

3. The integrated circuit of claim 1, wherein said multiplexer has inputs coupled to said respective I/O pin interface circuits.

4. The integrated circuit of claim 1, wherein each input of said multiplexer is connected to a plurality of different I/O pin interface circuits.

5. The integrated circuit of claim 1, wherein said multiplexer has an output connected to said analog circuit.

6. An integrated circuit having I/O pin interface circuits providing digital and analog functions, comprising:

at least one analog circuit formed on said integrated circuit;

a plurality of said I/O pin interface circuits formed on said integrated circuit, each said pin interface circuits functioning to couple therethrough digital and analog signals; and

a selector for selecting an analog path between at least one said pin interface circuits and said analog circuit.

7. The integrated circuit of claim 6, wherein ones of said I/O pin interface circuits each include an analog line connected to said selector.

8. The integrated circuit of claim 6, wherein said selector is adapted for carrying analog signals in a bidirectional manner.

9. The integrated circuit of claim 6, wherein said selector comprises a multiplexer controlled by a processor.

10. The integrated circuit of claim 9, wherein said multiplexer comprises a mux/demux, and further including an ADC and a DAC coupled to said mux/demux.

11. The integrated circuit of claim 6, further including a digital circuit for configuring said I/O pin interface circuits to couple digital signals therethrough.

12. The integrated circuit of claim 6, further including a circuit for allowing digital signals to be coupled to a pin interface circuit, and therethrough to said selector, and from said selector to an analog processing device.

13. The integrated circuit of claim 12, wherein said analog processing device comprises an ADC.

14. An integrated circuit having I/O pin interface circuits providing digital and analog functions, comprising:

digital circuits and at least one analog signal processing circuit formed on said integrated circuit;

a plurality of said I/O pin interface circuits, each said I/O pin interface circuit adapted for carrying analog and digital signals therethrough; and

a multiplexer coupled between said I/O pin interface circuits and said analog signal processing circuits, said multiplexer controlled so that analog signals can be coupled between said analog signal processing circuits and a selected one of said I/O pin interface circuits.

15. The integrated circuit of claim 14, wherein said multiplexer is adapted for carrying bidirectional analog signals therethrough.

16. The integrated circuit of claim 14, further including configuration circuits for configuring circuits in said I/O pin interface circuits for analog and digital operation.

17. The integrated circuit of claim 16, wherein said configuration circuits are registered and adapted for changing the configuration of said I/O pin interface circuits on the fly.

18. The integrated circuit of claim 14, further including a respective contact pad connected to each said I/O pin interface circuit, said contact pads connected to both analog and digital circuits in respective said I/O pin interface circuits.

19. The integrated circuit of claim 18, wherein said analog circuits in each said I/O pin interface circuits comprise a conductor for carrying ac signals.