Methods and systems for transmitting signals differentially and single-endedly across a pair of wires

• US 8,175,173 B2
• Filed: 04/20/2011
• Issued: 05/08/2012
• Est. Priority Date: 11/17/2006
• Status: Expired due to Fees

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Inventors: Shetty, Naresh B.
• Primary Examiner(s): Fan, Chieh M
• Assistant Examiner(s): Garcia, Santiago
• Application Number:
  US13/090,722
• Publication Number:
  US 20110194595A1
• Time in Patent Office: 384 Days
• Field of Search: 375/257
• US Class Current: 375/257
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission
• CPC Class Codes: H04L 25/45 using electronic distributors
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

Provided herein are systems and methods for transmitting signals across a pair of wires. In accordance with specific embodiments, a differential signal is transmitted across the pair of wires during one period of time, and two single-ended signals are transmitted across the same pair of wires during another period of time. Low voltage differential signaling (LVDS) can be used to transmit the differential signal across the pair of wires. In contrast, non-differential signaling can be used to transfer the two singled-ended signals across the same pair of wires.

Claims

1. A method for use by a transmitter, for transmitting signals from the transmitter across a pair of wires to a receiver, comprising:

(a) monitoring for the presence or absence of a predetermined signal that is indicative of whether or not video signals are being provided to the transmitter for transmission to the receiver;

(b) selecting one of a first mode of operation and a second mode of operation based on results of the monitoring for the presence or absence of the predetermined signal;

(c) transmitting differential signals across the pair of wires during a period of time when the first mode of operation is selected based on results of the monitoring, wherein the differential signals include video signals as well as Inter-Integrated Circuit (I2C) signals embedded with the video signals, wherein the I2C signals include a serial clock signal (SCL) and a serial data signal (SDA); and

(d) transmitting two single-ended signals across the same pair of wires during another period of time when the second mode of operation is selected based on results of the monitoring, wherein one of the two single-ended signals comprises the SCL I2C signal, the other one of the two single-ended signals comprises the SDA I2C signal, and neither of the two single-ended signals comprises a video signal.

2. The method of claim 1, wherein the predetermined signal, for which the presence or absence is being monitored for at step (a), comprises a signal that is selectively provided to the transmitter used for transmitting signals across the pair of wires.

3. The method of claim 1, wherein the predetermined signal comprises one of a data enable signal (DATAEN) and a processor clock signal (PCLK).

4. The method of claim 1, wherein step (b) comprises:

(b.1) selecting the first mode of operation if the predetermined signal is detected; and

(b.2) selecting the second mode of operation if the predetermined signal is not detected.

5. The method of claim 1, wherein:

the first mode of operation is an active mode; and

the second mode of operation is a sleep or standby mode.

6. The method of claim 5, wherein the sleep or standby mode is a reduced power mode as compared to the active mode.

23. The method of claim 1, wherein the transmitter is part of a first transceiver and the receiver is part of a second transceiver.

7. A method for transmitting signals across a pair of wires, comprising:

(a) monitoring for the presence or absence of a predetermined signal;

(b) selecting one of a first mode of operation and a second mode of operation based on results of the monitoring for the presence or absence of the predetermined signal;

(c) transmitting differential signals across the pair of wires during a period of time when the first mode of operation is selected based on results of the monitoring; and

(d) transmitting two single-ended signals across the same pair of wires during another period of time when the second mode of operation is selected based on results of the monitoring;

wherein at step (c) the differential signals being transmitted across the pair of wires comprise high speed signals as well as first and second low speed signals embedded with the high speed signals, wherein the high speed signals are transferred at a speed that is at least 1 MHz, and wherein the low speed signals are transferred at a speed of no more than 400 KHz; and

wherein at step (d) one of the two single-ended signals being transmitted across one of the wires comprises the first low speed signal, and the other one of the two single-ended signals being transmitted across the other one of the wires comprises the second low speed signal, and neither of the two single-ended signals comprise the high speed signals.

8. A method for transmitting signals across a pair of wires, comprising:

(a) monitoring for at least one of a data enable signal (DATAEN) and a processor clock signal (PCLK);

(b) selecting one of a first mode of operation and a second mode of operation based on results of the monitoring;

(c) transmitting differential signals across the pair of wires during a period of time when the first mode of operation is selected based on results of the monitoring; and

(d) transmitting two single-ended signals across the same pair of wires during another period of time when the second mode of operation is selected based on results of the monitoring;

wherein at step (c) the differential signals being transmitted across the pair of wires comprise high speed signals as well as first and second low speed signals embedded with the high speed signals, wherein the high speed signals are transferred at a speed that is at least 1 MHz, and wherein the low speed signals are transferred at a speed of no more than 400 KHz; and

wherein at step (d) one of the two single-ended signals being transmitted across one of the wires comprises the first low speed signal, and the other one of the two single-ended signals being transmitted across the other one of the wires comprises the second low speed signal, and neither of the two single-ended signals comprise the high speed signals.

9. The method of claim 8, wherein step (b) comprises:

(b.1) selecting the first mode of operation if the at least one of the data enable signal (DATAEN) and the processor clock signal (PCLK) is/are detected; and

(b.2) selecting the second mode of operation if the at least one of the data enable signal (DATAEN) and the processor clock signal (PCLK) is/are not detected.

10. The method of claim 8, wherein:

the first mode of operation is an active mode; and

the second mode of operation is a sleep or standby mode.

11. The method of claim 10, wherein the sleep or standby mode is a reduced power mode as compared to the active mode.

12. A method for use by a circuit that is configured to transmit signals across a pair of wires to a further circuit, comprising:

(a) monitoring for the presence or absence of a predetermined signal that is selectively provided to an input of the circuit and is indicative of whether video signals are being provided to the circuit for transmission to the further circuit;

(b) selecting one of a first mode of operation and a second mode of operation for the circuit based on results of the monitoring for the presence or absence of the predetermined signal;

(c) configuring the circuit to transmit differential signals across the pair of wires during a period of time when the first mode of operation is selected based on results of the monitoring for the presence or absence of the predetermined signal, wherein the differential signals include video signals as well as Inter-Integrated Circuit (I2C) signals embedded with the video signals, wherein the I2C signals include a serial clock signal (SCL) and a serial data signal (SDA); and

(d) configuring the circuit to transmit two single-ended signals across the same pair of wires during another period of time when the second mode of operation is selected based on results of the monitoring for the presence or absence of the predetermined signal, wherein one of the two single-ended signals comprises the SCL I2C signal, the other one of the two single-ended signals comprises the SDA I2C signal, and neither of the two single-ended signals comprises a video signal.

13. The method of claim 12, wherein the predetermined signal comprises one of a data enable signal (DATAEN) and a processor clock signal (PCLK).

14. The method of claim 12, wherein the second mode of operation is a reduced power mode as compared to the first mode of operation.

15. The method of claim 14, wherein step (b) comprises:

(b.1) selecting the first mode of operation if the predetermined signal is detected; and

(b.2) selecting the second mode of operation if the predetermined signal is not detected.

16. A method for use by a circuit that is configured to transmit signals across a pair of wires, comprising:

(a) monitoring for the presence or absence of a predetermined signal that is selectively provided to an input of the circuit;

(b) selecting one of a first mode of operation and a second mode of operation for the circuit based on results of the monitoring for the presence or absence of the predetermined signal;

(c) configuring the circuit to transmit differential signals across the pair of wires during a period of time when the first mode of operation is selected based on results of the monitoring for the presence or absence of the predetermined signal; and

(d) configuring the circuit to transmit two single-ended signals across the same pair of wires during another period of time when the second mode of operation is selected based on results of the monitoring for the presence or absence of the predetermined signal;

wherein at step (c) the differential signals being transmitted across the pair of wires comprise high speed signals as well as first and second low speed signals embedded with the high speed signals, wherein the high speed signals are transferred at a speed that is at least 1 MHz, and wherein the low speed signals are transferred at a speed of no more than 400 KHz; and

wherein at step (d) one of the two single-ended signals being transmitted across one of the wires comprises the first low speed signal, and the other one of the two single-ended signals being transmitted across the other one of the wires comprises the second low speed signal, and neither of the two single-ended signals comprise the high speed signals.

17. A mode controller configured to control how transmitter circuitry transmits signals across a pair of wires, wherein the mode controller is configured to:

determine whether a predetermined signal is detected at a predetermined terminal, wherein detection of the predetermined signal at the predetermined terminal is indicative of whether video signals are being provided to the transmitter circuitry for transmission to receiver circuitry;

select one of a first mode of operation and a second mode of operation based on whether the predetermine signal is detected at the predetermined terminal;

configure the transmitter circuitry to transmit differential signals across the pair of when the first mode of operation is selected, wherein the differential signals include video signals as well as Inter-Integrated Circuit (I2C) signals embedded with the video signals, wherein the I2C signals include a serial clock signal (SCL) and a serial data signal (SDA); and

configure the transmitter circuitry to transmit two single-ended signals across the same pair of wires when the second mode of operation is selected, wherein one of the two single-ended signals comprises the SCL I2C signal, the other one of the two single-ended signals comprises the SDA I2C signal, and neither of the two single-ended signals comprises a video signal.

18. The mode controller of claim 17, wherein the predetermined signal comprises one of a data enable signal (DATAEN) and a processor clock signal (PCLK), and wherein the predetermined terminal comprises an input terminal configured to accept the one of the data enable signal (DATAEN) and the processor clock signal (PCLK).

19. The mode controller of claim 17, wherein the second mode of operation is a reduced power mode as compared to the first mode of operation.

24. The mode controller of claim 17, wherein the transmitter circuitry is part of a transceiver.

20. A system, comprising:

transmitter circuitry configured to transmit signals across a pair of wires connected to a pair of outputs of the transmitter circuitry; and

a mode controller configured to control how the transmitter circuitry transmits signals across the pair of wires;

wherein the mode controller is configured to

determine whether a predetermined signal is detected at a predetermined terminal;

select one of a first mode of operation and a second mode of operation based on whether the predetermine signal is detected at the predetermined terminal;

configure the transmitter circuitry to transmit differential signals across the pair of when the first mode of operation is selected; and

configure the transmitter circuitry to transmit two single-ended signals across the same pair of wires when the second mode of operation is selected,

wherein detection of the predetermined signal at the predetermined terminal is indicative of whether video signals are being provided to the transmitter circuitry for transmission to receiver circuitry;

wherein the differential signals include video signals as well as Inter-Integrated Circuit (I2C) signals embedded with the video signals, wherein the I2C signals include a serial clock signal (SCL) and a serial data signal (SDA); and

wherein one of the two single-ended signals comprises the SCL I2C signal, the other one of the two single-ended signals comprises the SDA I2C signal, and neither of the two single-ended signals comprises a video signal.

21. The system of claim 20, wherein the predetermined signal comprises one of a data enable signal (DATAEN) and a processor clock signal (PCLK), and wherein the predetermined terminal comprises an input terminal configured to accept the one of the data enable signal (DATAEN) and the processor clock signal (PCLK).

22. The system of claim 20, wherein the second mode of operation is a reduced power mode as compared to the first mode of operation.