Methods and apparatus for enabling and disabling scrambling of control symbols

• US 9,979,570 B2
• Filed: 09/19/2016
• Issued: 05/22/2018
• Est. Priority Date: 01/31/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Whitby-Strevens, Colin
• Primary Examiner(s): Yu, Lihong
• Application Number:
  US15/269,831
• Publication Number:
  US 20170070372A1
• Time in Patent Office: 610 Days
• Field of Search: 375257
• CPC Class Codes: G09G 2330/06 Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation
• CPC Class Codes: G09G 2370/12 Use of DVI or HDMI protocol in interfaces along the display data pipeline
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: H04L 25/03866 using scrambling
• CPC Class Codes: H04L 25/08 Modifications for reducing interference; Modifications for reducing effects due to line faults ; Receiver end arrangements for detecting or overcoming line faults
• CPC Class Codes: H04N 21/43635 HDMI

Abstract

Methods and apparatus for the selection and/or configuration of scrambling operations to accommodate e.g., both scrambling and non-scrambling connections (such as to e.g., legacy type devices). In one embodiment, media interface devices (such as e.g., HDMI (High-Definition Multimedia Interface)) devices may provide enhanced scrambling capabilities; solutions disclosed herein provide, among other things, support for both enhanced scrambling capable devices and legacy devices, and enable a device to determine the scrambling capabilities of a connected device.

Claims

1. A computerized apparatus comprising:

a processor apparatus;

an audio-visual interface in data communication with the processor apparatus, the audio-visual interface configured to transmit a clock signal; and

a non-transitory computer-readable apparatus having a computer program stored thereon, the computer program comprising a plurality of instructions that are configured to, when executed by the processor apparatus, cause the computerized apparatus to;

establish a connection to a sink device via the audio-visual interface;

determine whether the sink device supports one or more scrambling functionalities;

when the one or more scrambling functionalities are not enabled, default to a legacy mode; and

when a scrambling functionality is enabled, (i) reduce an amplitude of the clock signal relative to that of the legacy mode, and (ii) transmit the reduced amplitude clock signal.

2. The computerized apparatus of claim 1, wherein the one or more scrambling functionalities are determined based on contents of a configuration register of the sink device.

3. The computerized apparatus of claim 1, wherein the computer program is further configured to, when executed by the processor apparatus, cause the computerized apparatus to:

select the scrambling functionality from the supported one or more scrambling functionalities when the one or more scrambling functionalities are supported by the sink device; and

otherwise

operate according to the legacy mode.

4. The computerized apparatus of claim 3, wherein the operation according to the legacy mode is limited to a subset of data rates.

5. The computerized apparatus of claim 1, wherein the audio-visual interface comprises a High Definition Multimedia (HDMI)-compliant interface.

6. The computerized apparatus of claim 1, wherein:

the clock signal is embedded within a unidirectional packet-based network protocol.

7. The computerized apparatus of claim 1, wherein:

the scrambling functionality is enabled when exceeding a threshold data rate.

8. The computerized apparatus of claim 7, wherein the one or more scrambling functionalities are not enabled when the threshold data rate is not exceeded.

9. A method of selectively enabling clock scrambling functionality, the method comprising:

establishing a connection between a sink device and a source device via an audio-visual interface;

determining whether scrambling functionality is supported by the sink device and the source device; and

when the scrambling functionality is supported, reducing an amplitude of a clock signal relative to an amplitude associated with a legacy operation; and

otherwise

when the scrambling functionality is not supported, setting the clock signal to the amplitude associated with the legacy operation.

10. The method of claim 9, wherein the determining of whether the scrambling functionality is supported comprises transacting one or more messages.

11. The method of claim 10, wherein the transacting of the one or more messages comprises reading a register that indicates the scrambling functionality.

12. The method of claim 9, wherein the determining of the scrambling functionality is based on determining a pre-agreed usage case.

13. The method of claim 9, wherein the determining of the scrambling functionality is based on determining a data rate.

14. The method of claim 13, further comprising reducing an electro-magnetic interference (EMI) characteristic of the clock signal by using the scrambling functionality.

15. A non-transitory computer-readable apparatus comprising a storage medium having at least one computer program stored thereon, the computer program comprising a plurality of instructions configured to, when executed by a processor apparatus, cause the processor apparatus to:

establish a connection between a sink device and a source device via an audio-visual interface;

determine whether a scrambling functionality is supported by the sink device and the source device;

when the scrambling functionality is enabled, reduce an amplitude of a transmitted clock signal relative to an amplitude associated with a legacy operation; and

otherwise

when the scrambling functionality is disabled, transmit a clock signal at the amplitude associated with the legacy operation.

16. The non-transitory computer-readable apparatus of claim 15, wherein the plurality of instructions are further configured to, when executed by the processor apparatus, cause the processor apparatus to negotiate the scrambling functionality between the sink device and the source device when the scrambling functionality is enabled.

17. The non-transitory computer-readable apparatus of claim 15, wherein the scrambling functionality is determined based on contents of a configuration register of the sink device.

18. The non-transitory computer-readable apparatus of claim 15, wherein the scrambling functionality is enabled when a threshold data rate is exceeded.

19. The non-transitory computer-readable apparatus of claim 18, wherein the scrambling functionality is disabled when the threshold data is not exceeded.

20. The non-transitory computer-readable apparatus of claim 15, wherein the plurality of instructions are further configured to, when executed by the processor apparatus, cause the processor apparatus to determine the scrambling capability based on a presence or an absence of an expected symbol during transmission via the audio-visual interface.