SYSTEM AND METHOD FOR TRANSMITTING USB DATA OVER A DISPLAYPORT TRANSMISSION LINK

• US 20130080665A1
• Filed: 09/22/2011
• Published: 03/28/2013
• Est. Priority Date: 09/22/2011
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Ji Park, Prashant Shamarao
• Inventors: PARK, Ji, SHAMARAO, Prashant
• Granted Patent: US 9,323,698 B2
• Time in Patent Office: Days
• US Class Current: 710/60
• CPC Class Codes: G06F 13/14 Handling requests for interconnection or transfer
• CPC Class Codes: G06F 13/4265 on a point to point bus G06F13/4247, G06F13/4282 take precedence
• CPC Class Codes: G09G 2370/04 Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
• CPC Class Codes: G09G 2370/045 using multiple communication channels, e.g. parallel and serial
• CPC Class Codes: G09G 2370/10 Use of a protocol of communication by packets 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 12/4013 Management of data rate on the bus systems modifying transmission characteristics according to link quality H04L1/0001
• CPC Class Codes: H04L 67/565 Conversion or adaptation of application format or content adding application control or application functional data H04L67/561
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion

Abstract

A data transmission system is provided. The data transmission system includes a source device having a source device controller and a register and a sink device having a sink device controller. The data transmission system also includes a transmission link coupling the source device and the sink device. The transmission link includes a unidirectional main line having a plurality of main link channels, a bidirectional auxiliary line configured to transmit data between the source device and the sink device at a first data rate, and a unidirectional interrupt line. The transmission link is configured to transmit data from the source device to the sink device over one of the main link lines at a second data rate and to transmit data from the sink device to the source device over the auxiliary line at the second data rate. The transmission link may comply with the DisplayPort standard, and the data may be transmitted in accordance with the USB standard.

Claims

1. A method of transmitting data between a source device coupled to a sink device, comprising:

receiving, at the source device, a first instruction to transmit data between the source device and the sink device at a first data rate;

transmitting data from the source device to the sink device at the first data rate over a unidirectional line; and

transmitting data from the sink device to the source device at the first data rate over a bidirectional line, wherein the bidirectional line typically transmits data at a second data rate that is slower than the first data rate.

2. The method of claim 1, wherein the unidirectional line comprises a main link line of a DisplayPort connection and the bidirectional line comprises a fast auxiliary line of the DisplayPort connection.

3. The method of claim 1, wherein the first data rate corresponds to a data rate associated with a Universal Serial Bus (USB) revision 3.0 standard.

4. The method of claim 1, wherein the first instruction comprises a write to a DisplayPort Configuration Data (DPCD) register.

5. The method of claim 1, further comprising:

receiving, at the source device, a second instruction to stop data transmission between the source device and the sink device.

6. The method of claim 5, wherein the second instruction comprises a Hot Plug Detect (HPD) interrupt signal.

7. The method of claim 5, wherein the unidirectional line comprises a plurality of unidirectional lines, the data being transmitted between the source device and the sink device at the first data rate over a first unidirectional line and audio and video data being transmitted over the remaining unidirectional lines at a third data rate.

8. The method of claim 1, wherein transmitting data from the sink device to the source device at the first data rate over a bidirectional line comprises transmitting only the data from the sink device to the source device when the bidirectional line is transmitting data at the first data rate.

9. A method for transmitting Universal Serial Bus (USB) data over a DisplayPort link coupling a sink device to a source device, comprising:

receiving a first instruction at the source device to transmit the USB data over the DisplayPort link;

transmitting the USB data over a fast auxiliary line of the DisplayPort link from the source device to the sink device at a first data rate; and

transmitting the USB data over the fast auxiliary line from the sink device to the source device at the first data rate, wherein;

the USB data transmission between the source device and the sink device comprises alternating half-duplex unidirectional transmission.

10. The method of claim 9, wherein the first data rate corresponds to a data rate associated with a USB revision 3.0 standard.

11. The method of claim 9, wherein the first instruction comprises a write to a DisplayPort Configuration Data (DPCD) register.

12. The method of claim 9, further comprising:

receiving, at the source device, a second instruction to bidirectionally transmit auxiliary data between the source device and the sink device at a second data rate.

13. The method of claim 12, wherein the second instruction comprises a Hot Plug Detect (HPD) interrupt signal.

14. A data transmission system, comprising:

a source device, the source device comprising a source device controller having a register;

a sink device, the sink device comprising a sink device controller; and

a transmission link coupling the source device and the sink device, the transmission link comprising;

a unidirectional main line comprising a plurality of main link channels;

a bidirectional auxiliary line, the bidirectional auxiliary line configured to transmit data between the source device and the sink device at a first data rate; and

a unidirectional interrupt line, wherein;

the transmission link is configured by the source device controller to transmit data from the source device to the sink device over one of the plurality of main link lines at a second data rate and to transmit data from the sink device to the source device over the auxiliary line at the second data rate in response to a first instruction written to the register.

15. The system of claim 14, wherein the second data rate corresponds to a data rate associated with a Universal Serial Bus revision 3.0 standard.

16. The system of claim 14, wherein the data transmission system comprises a DisplayPort data transmission system.

17. The system of claim 16, wherein audio/video data is transmitted between the source device and the sink device over the remaining main link lines.

18. The system of claim 15, wherein the transmission link is configured by the source device controller to transmit data from the source device to the sink device at the first data rate in response to a second instruction written in the register.

19. The system of claim 18, wherein the second instruction comprises a Hot Plug Detect (HPD) interrupt signal.

20. The system of claim 14, wherein the transmission system is configured by the source device controller to only transmit data from the sink device to the source device at the second data rate over the auxiliary line.

21. A data transmission system, comprising:

a source device, the source device comprising a source device controller having a register;

a sink device, the sink device comprising a sink device controller; and

a transmission link coupling the source device and the sink device, the transmission link comprising;

a unidirectional main line comprising a plurality of main link lines;

a bidirectional auxiliary line; and

a unidirectional interrupt line, wherein;

the transmission link is configured by the source device controller to transmit data from the source device to the sink device over a first main link line and to transmit data from the sink device to the source device over a second main link line in response to a first instruction written to the register.

22. The system of claim 21, wherein the data transmission system comprises a DisplayPort data transmission system and the transmitted data is transmitted at a data rate corresponding to a Universal Serial Bus revision 3.0 standard.

24. The system of claim 21, wherein the transmission link is configured to stop data transmission between the source device and the sink device in response to a second instruction written in the register.

25. The system of claim 24, wherein the second instruction comprises a Hot Plug Detect (HPD) interrupt signal transmitted over the unidirectional interrupt line.

26. The system of claim 21, wherein the plurality of main link lines other than the first and second main link lines are configured by the source device controller and the sink device controller to transmit data at a higher data rate than a baseline data rate associated with the plurality of main link lines.

27. The system of claim 21, wherein the plurality of main link lines other than the first and second main link lines transmit audio/video data from the source device to the sink device.

23. The system of claim 23, wherein a data transmission direction of the second main link line is reversed to enable transmission of data from the sink device to the source device over the second main link line.

28. A method of transmitting data between a source device and a sink device, comprising:

receiving, at the source device, instructions to transmit data between the source device and the sink device;

configuring a first main line link of a plurality of main line links in a main line coupling the source device and the sink device to transmit data from the source device to the sink device;

configuring a second main line link of the plurality of main line links to transmit data from the sink device to the source device;

transmitting data from the source device to the sink device over the first main line link; and

transmitting data from the sink device to the source device over the second main line link.

29. The method of claim 28, wherein the main line coupling the source device and the sink device comprises a main line of a DisplayPort data transmission link.

30. The method of claim 28, transmitting data from the source device to the sink device and transmitting data from the sink device to the source device comprises transmitting data in accordance with a Universal Serial Bus (USB) revision 3.0 standard.

31. The method of claim 28, wherein receiving instructions comprises writing to a DisplayPort Configuration Data (DPCD) register in a source device controller of the source device.

32. The method of claim 28, further comprising:

receiving, at the source device, an interrupt signal transmitted over an interrupt line; and

stopping the transmission of data from the source device to the sink device and from the sink device to the source device.