Integrated modem and line-isolation circuitry with command mode and data mode control and associated method

• US 6,662,238 B1
• Filed: 01/10/2000
• Issued: 12/09/2003
• Est. Priority Date: 07/23/1999
• Status: Expired due to Fees

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Reid, Mitchell, Dupuis, Timothy J.
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): Mai, Rijue
• Application Number:
  US09/480,726
• Time in Patent Office: 1,429 Days
• Field of Search: 710/1, 710/5, 710/20, 710/7, 710/8, 710/15, 710/29, 710/61, 710/65, 712/225, 712/221, 712/220, 712/229, 375/222, 379/93.05
• US Class Current: 710/1
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: H04L 25/4927 using levels matched to the quantisation levels of the channel
• CPC Class Codes: H04L 27/00 Modulated-carrier systems

Abstract

An improved modem architecture and associated method are disclosed that integrate modem functionality and line-side isolation functionality while also providing a modem interface that allows command and data mode control.

Claims

1. An integrated modem and line-isolation circuit with modem command mode and data mode control, comprising:

system-side line-isolation circuitry capable of being coupled to an isolation barrier;

digital signal processing (DSP) circuitry integrated with the system-side line-isolation circuitry, the DSP circuitry having a modem processor for modem data and a digital processor for system-side circuitry; and

an asynchronous serial communication interface coupled to the DSP circuitry and configured to be coupled to an external system-side device, the asynchronous serial communication interface including a serial input pin configured to receive an M-bit word, wherein M-minus-N bits of the M-bit word are data bits and N-bits of the M-bit word are control bits, the control bits identifying whether the modem processor should process the M-minus-N bits of the M-bit word in command mode or in data mode.

2. The integrated modem and line-isolation circuit of claim 1, wherein the M-bit word is a 9-bit word with 8 bits being for data and 1-bit being for control.

3. The integrated modem and line-isolation circuit of claim 2, wherein the single control bit is the last bit of the 9-bit word received through the serial input pin.

4. The integrated modem and line-isolation circuit of claim 1, wherein the serial input pin also receives a start bit before receiving the M-bit word and a stop bit after receiving the M-bit word.

5. The integrated modem and line-isolation circuit of claim 1, wherein the system-side line-isolation circuitry is capable of sending digital information across the isolation barrier.

6. The integrated modem and line-isolation circuit of claim 5, wherein the isolation barrier utilizes a capacitively isolated barrier.

7. The integrated modem and line-isolation circuit of claim 6, wherein digital information is communication across the capacitively isolated barrier.

8. The integrated modem and line-isolation circuit of claim 1, wherein the digital processor comprises digital filters for digital data received across the isolation barrier from the communication line and a digital modulator for digital data transmitted across the isolation barrier to the communication line.

9. The modem and line-isolation integrated circuit of claim 1, wherein the system-side line-isolation circuitry provides system-side phone line direct access arrangement functionality.

10. A method for controlling whether modem circuitry within an integrated modem and line-isolation circuit operates in command mode or data mode, comprising:

providing an asynchronous serial communication interface coupled to modem circuitry within an integrated modem and line-isolation circuit, the asynchronous serial interface including a serial input pin and being configured to be coupled to an external system-side device;

receiving an M-bit word through the serial input pin;

utilizing N-bits of the M-bit word as control bits; and

determining whether the modem circuitry processes M-minus-N bits of the M-bit word in command mode or data mode based upon the state of the N control bits.

11. The method of claim 10, wherein the M-bit word is a 9-bit word with 8 bits being for data and 1-bit being for control.

12. The method of claim 11, wherein the single control bit is the last bit of the 9-bit word received through the serial input pin.

13. The method of claim 11, further comprising receiving a start bit before receiving the M-bit word and receiving a stop bit after receiving the M-bit word.

14. A method for providing modem command mode and data mode control for a modem and line-isolation integrated circuit, comprising:

providing a system-side line-isolation integrated circuit including digital-signal-processing (DSP) circuitry having a modem processor for modem data and a digital processor for system-side circuitry;

providing an asynchronous serial communication interface within the system-side line-isolation integrated circuit configured to be coupled to an external system-side device, the asynchronous serial communication interface including a serial input pin for the system-side line-isolation integrated circuit;

receiving an M-bit word through the serial input pin;

utilizing N-bits of the M-bit word as control bits; and

determining whether the modem processor processes M-minus-N bits of the M-bit word in command mode or data mode based upon the state of the N control bits.

15. The method of claim 14, further comprising communicating digital information through an isolation barrier between the system-side line-isolation integrated circuit and a line-side line-isolation integrated circuit.

16. The method of claim 15, wherein the isolation barrier is a capacitively isolated barrier.

17. The method of claim 16, wherein digital information is communication across the capacitively isolated barrier.

18. The method of claim 16, wherein the M-bit word is a 9-bit word with 8 bits being for data and 1-bit being for control.