METHODS AND APPARATUS FOR SIGNALING ON A DIFFERENTIAL LINK

• US 20130114747A1
• Filed: 12/24/2012
• Published: 05/09/2013
• Est. Priority Date: 03/14/2002
• Status: Active Grant

• Current Assignee: Theodore Schoenborn
• Original Assignee: Theodore Schoenborn
• Inventors: Schoenborn, Theodore
• Granted Patent: US 8,885,735 B2
• Time in Patent Office: Days
• US Class Current: 375/257
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission
• CPC Class Codes: H04L 25/028 Arrangements specific to the transmitter end
• CPC Class Codes: H04L 25/0292 Arrangements specific to the receiver end
• CPC Class Codes: H04L 25/4917 using multilevel codes

Abstract

Methods and apparatus are disclosed for transitioning a receiver from a first state to a second state using an in-band signal over a differential serial data link.

Claims

1. An apparatus comprising:

a receiver to;

enter a reduced power state;

identify a differential signal transmitted over a differential, point-to-point serial data link;

interpret the signal as a wake signal; and

transition from the reduced power state to a normal power state based at least in part on the wake signal.

2. The apparatus of claim 1, wherein the receiver is further configured to identify an idle condition on the data link in excess of a predetermined length of time and the receiver is to enter the reduced power state based on the identification of the idle condition.

3. The apparatus of claim 2, wherein the idle condition is to be interpreted as an in-band signal to enter the reduced power state.

4. The apparatus of claim 1, wherein the receiver does not receive data when in the reduced power state.

5. The apparatus of claim 1, wherein the reduced power state is a non-zero power state.

6. The apparatus of claim 1, wherein the signal comprises an in-band signal.

7. The apparatus of claim 6, wherein the signal comprises a direct current (DC) signal.

8. The apparatus of claim 7, wherein the signal comprises a predetermined differential voltage condition for at least a predetermined time period.

9. The apparatus of claim 6, wherein the signal comprises an alternating current (AC) switching signal.

10. The apparatus of claim 9, wherein the signal comprises dummy data.

11. The apparatus of claim 1, wherein the receiver comprises a plurality of sections and the signal comprises information that identifies a particular one of the plurality of sections to awake.

12. An apparatus comprising:

a transmitter to;

transmit an in-band power management signal to a receiver over a differential, point-to-point serial data link, wherein the signal comprises a wake signal to prompt the receiver to transition from a reduced power state to a normal power state; and

transmit data to the receiver over the data link while the receiver is in the normal power state.

13. The apparatus of claim 12, wherein the signal is to comprise a direct current (DC) signal.

14. The apparatus of claim 13, wherein the signal is to comprise a predetermined differential voltage condition for at least a predetermined time period.

15. The apparatus of claim 14, wherein the signal is to be generated by applying a voltage to a particular one of the at least two lines.

16. The apparatus of claim 12, wherein the signal is to comprise an alternating current (AC) switching signal.

17. An apparatus comprising:

a first receiver to use a first differential, point-to-point serial data link including at least two lines, wherein the first data link is included in a pair of differential, point-to-point serial data links, and the first receiver is to;

identify an idle condition on the first data link in excess of a predetermined length of time;

enter a reduced power state responsive to identifying the idle condition;

identify a differential signal transmitted over the first data link including at least two lines;

interpret the signal as representing an exit from the idle condition; and

transition from the reduced power state to a normal power state responsive to the wake signal.

18. The apparatus of claim 17, further comprising a transmitter to use a second data link in the pair of data links, wherein the transmitter is to:

transmit wake signals over the second data link to prompt a second receiver to transition from a reduced power state to a normal power state.

19. A system comprising:

a data link comprising a differential, point-to-point serial data link;

a first device;

a second device communicatively coupled to the first device using the data link, the second device configured to;

identify an idle condition on the data link;

enter a reduced power state based at least in part on the idle condition;

receive a differential signal transmitted over the data link from the first device;

interpret the signal as a wake signal; and

transition from the reduced power state to a normal power state based at least in part on the wake signal.

20. The system of claim 19, wherein the data link permits data transfer between the first and second devices in excess of 2.5 Gbit per second.

21. The system of claim 19, wherein the data link is a first data link, the system further comprising a second differential, point-to-point serial data link communicatively coupling the first and second devices.

22. A method comprising:

entering a reduced power state;

identifying a differential signal transmitted over a differential, point-to-point serial data link;

interpreting the signal as a wake signal; and

transitioning from the reduced power state to a normal power state based at least in part on the wake signal.

23. The method of claim 22, further comprising:

identifying an idle condition on the data link in excess of a predetermined length of time; and

entering the reduced power state based on the identification of the idle condition.

24. The method of claim 23, wherein the idle condition is interpreted as an in-band signal to enter the reduced power state.

25. The method of claim 22, wherein the receiver does not receive data when in the reduced power state.

26. The method of claim 22, further comprising communicating over the link while in the normal power state.