High data rate interface apparatus and method

• US 8,630,318 B2
• Filed: 01/29/2010
• Issued: 01/14/2014
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Anderson, Jon James, Steele, Brian, Wiley, George Alan, Shekhar, Shashank
• Primary Examiner(s): Zhou, Yong
• Application Number:
  US12/696,272
• Publication Number:
  US 20100128626A1
• Time in Patent Office: 1,446 Days
• Field of Search: None
• US Class Current: 370/519
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6483 Video, e.g. MPEG
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/61 for supporting one-way streaming services, e.g. Internet radio
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 67/125 involving control of end-device applications over a network
• CPC Class Codes: H04L 67/75 Indicating network or usage conditions on the user display
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04M 1/72409 by interfacing with external accessories hands-free H04M1/60
• CPC Class Codes: H04M 1/72412 using two-way short-range wireless interfaces
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A data interface for transferring digital data between a host and a client over a communication path using packet structures linked together to form a communication protocol for communicating a pre-selected set of digital control and presentation data. The signal protocol is used by link controllers configured to generate, transmit, and receive packets forming the communications protocol, and to form digital data into one or more types of data packets, with at least one residing in the host device and being coupled to the client through the communications path. The interface provides a cost-effective, low power, bi-directional, high-speed data transfer mechanism over a short-range “serial” type data link, which lends itself to implementation with miniature connectors and thin flexible cables which are especially useful in connecting display elements such as wearable micro-displays to portable computers and wireless communication devices.

Claims

1. A method for reverse data sampling of a data link in a mobile display digital interface (MDDI) system, the method comprising the steps of:

sending a round trip delay measurement packet from a host to a client over the data link, the round trip delay measurement packet including a measurement period field having a duration and allowing the client to send to the host over the data link a data sequence during the duration of the measurement period field;

measuring, by the host, a round trip delay of the data link by detecting a first bit of the data sequence sent by the client;

determining a number of forward link clock periods per reverse data bit, the reverse data bit being a bit of the data sequence;

computing a remainder of a division of the round trip delay by the number of forward link clock periods per reverse data bit;

computing an offset by subtracting either one or two from the computed remainder; and

determining a sampling point to start sampling reverse data based on the computed offset.

2. The method of claim 1 wherein the step of measuring the round trip delay comprises measuring a propagation delay from the host to the client and from the client to the host.

3. The method of claim 1 further comprising determining a reverse link rate divisor based on the measured round trip delay.

4. A hardware system for reverse data sampling of a data link in a mobile display digital interface (MDDI) system, the system comprising:

means for sending a round trip delay measurement packet from a host to a client over the data link, the round trip delay measurement packet including a measurement period field having a duration and allowing the client to send to the host over the data link a data sequence during the duration of the measurement period field;

means for measuring, by the host, a round trip delay of the data link by detecting a first bit of the data sequence sent by the client;

means for determining a number of forward link clock periods per reverse data bit, the reverse data bit being a bit of the data sequence;

means for computing a remainder of a division of the round trip delay by the number of forward link clock periods per reverse data bit;

means for computing an offset by subtracting either one or two from the computed remainder; and

means for determining a sampling point to start sampling reverse data based on the computed offset.

5. The system of claim 4 wherein the means for measuring the round trip delay comprises a means for measuring a propagation delay from the host to the client and from the client to the host.

6. The system of claim 4 further comprising a means for determining a reverse link rate divisor based on the measured round trip delay.

7. A non-transitory computer readable medium comprising program code which is hardware computer-executable to implement reverse data sampling of a data link in a mobile display digital interface (MDDI) system, the program code comprising program instructions that, when executed by a computer, cause the computer to:

send a round trip delay measurement packet from a host to a client over the data link, the round trip delay measurement packet including a measurement period field having a duration and allowing the client to send to the host over the data link a data sequence during the duration of the measurement period field;

measure, at the host, a round trip delay of the data link by detecting a first bit of the data sequence sent by the client;

determine a number of forward link clock periods per reverse data bit, the reverse data bit being a bit of the data sequence;

compute a remainder of a division of the round trip delay by the number of forward link clock periods per reverse data bit;

compute an offset by subtracting either one or two from the computed remainder; and

determine a sampling point to start sampling reverse data based on the computed offset.

8. The computer readable medium of claim 7 wherein the program instructions that cause the computer to measure the round trip delay comprise program instructions that cause the computer to measure a propagation delay from the host to the client and from the client to the host.

9. The computer readable medium of claim 7 further comprising program instructions that, when executed by the computer, cause the computer to determine a reverse link rate divisor based on the measured round trip delay.

10. A method of determining a data rate between a host and a client in a mobile display digital interface (MDDI) system, the method comprising the steps of:

selecting by the host a pre-calibration minimum data rate at which the client can operate;

requesting a client capability packet by the host from the client;

receiving by the host the client capability packet, the client capability packet comprising a pre-calibration data rate capability field having a first value specifying a maximum data rate at which the client can operate prior to performing forward link skew calibration and a post-calibration data rate capability field having a second value specifying a maximum data rate at which the client can operate after performing forward link skew calibration;

sending by the host a forward link skew calibration packet to the client, the forward link skew calibration packet including a calibration data sequence allowing the client to perform forward link skew calibration;

selecting by the host a data rate less than or equal to the second value of the post-calibration data rate capability field; and

operating at the selected data rate.

11. A hardware system for determining a data rate between a host and a client in a mobile display digital interface (MDDI) system comprising:

means for selecting by the host a pre-calibration minimum data rate at which the client can operate;

means for requesting a client capability packet by the host from the client;

means for receiving by the host the client capability packet, the client capability packet comprising a pre-calibration data rate capability field having a first value specifying a maximum data rate at which the client can operate prior to performing forward link skew calibration and a post-calibration data rate capability field having a second value specifying a maximum data rate at which the client can operate after performing forward link skew calibration;

means for sending by the host a forward link skew calibration packet to the client, the forward link skew calibration packet including a calibration data sequence allowing the client to perform forward link skew calibration;

means for selecting by the host a data rate less than or equal to the second value of the post-calibration data rate capability field; and

means for operating at the selected data rate.

12. A non-transitory computer readable medium comprising program code which is hardware computer-executable to implement a determination of a data rate between a host and a client in a mobile display digital interface (MDDI) system, the program code comprising program instructions that, when executed by a computer, cause the computer to:

select, at the host, a pre-calibration minimum data rate at which the client can operate;

request, at the host, a client capability packet from the client;

receive, at the host, the client capability packet, the client capability packet comprising a pre-calibration data rate capability field having a first value specifying a maximum data rate at which the client can operate prior to performing forward link skew calibration and a post-calibration data rate capability field having a second value specifying a maximum data rate at which the client can operate after performing forward link skew calibration;

send, from the host, a forward link skew calibration packet to the client, the forward link skew calibration packet including a calibration data sequence allowing the client to perform forward link skew calibration;

select, at the host, a-data rate less than or equal to the second value of the post-calibration data rate capability field; and

operate at the selected data rate.