Control bus for connection of electronic devices
View Patent ↗A method and apparatus for a control bus for connection of electronic devices. An embodiment of a method includes coupling a transmitting device to a receiving device, including connecting a control bus between the transmitting device and the receiving device, with the control bus being a bi-directional, single-line bus. The method further includes obtaining control of the control bus for either the transmitting device or the receiving device, with the device obtaining control becoming an initiator and the other device becoming a follower. One or more control signals are converted to one or more data packets, with each of the one or more control signals representing one of multiple different types of control signals. The generated data packets are transmitted from the initiator to the follower via the control bus.
1. A method comprising:
coupling a first device to a second device, the first device being one of a transmitting device or a receiving device and the second device being the other of a transmitting device or a receiving device, coupling of the first and second devices including connecting a first control bus between the first device and the second device, the first control bus being a bi-directional, single-line bus;
determining whether the first control bus is in use by the second device;
if the first control bus is not in use by the second device, conducting arbitration for control of the first control bus; and
if the first device obtains control of the first control bus through the arbitration for control of the first control bus, the first device becoming an initiator and the second device becoming a follower, then further comprising:
converting one or more control signals for a standard protocol to one or more data packets, each of the one or more control signals representing one of a plurality of different types of control signals, each data packet including a plurality of bits to be transmitted; and
transmitting the generated data packets from the first device to the second device via the first control bus, and wherein the receiving device is a device utilizing the standard protocol and the transmitting device is a mobile device utilizing a modified protocol, the modified protocol being a modification of the standard protocol that is not included in the standard protocol.
2. The method of claim 1 , wherein the signaling for transmitting the one or more generated data packets on the first control bus utilizes bi-phase mark encoding.
3. The method of claim 1 , wherein if the second device obtains control of the first control bus, the second device becoming the initiator and the first device becoming the follower, then further comprising:
receiving at the first device the plurality of data packets transmitted from the second device.
4. The method of claim 1 , wherein, if the first device is a transmitting device for transmission of data to the second device, then arbitrating for control of the first control bus includes:
determining the first control bus is idle or unused for a first time period;
if the first control bus is idle or unused for the first time period, then sending a low signal for a first number of cycles; and
after the conclusion of the first number of cycles, then taking control of the first control bus.
5. The method of claim 1 , wherein, if the first device is a receiving device for reception of data from the second device, then arbitrating for control of the first control bus includes:
determining the first control bus is idle or unused for a first time period;
if the first control bus is idle or unused for the first time period, then sending a low signal followed by a high signal for a first number of cycles;
during the first number of cycles, checking a status of the first control bus;
if the status of the first control bus is a high signal, taking control of the first control bus.
6. The method of claim 1 , wherein the standard protocol is HDMI (High-Definition Multimedia Interface).
7. The method of claim 1 , wherein the receiving device is a dual-mode device that is capable of communicating with a device that is compatible with the standard protocol or a device that is compatible with the modified protocol.
8. The method of claim 1 , wherein standard protocol requires that the plurality of different types of control signals be transmitted over a plurality of different control buses.
9. The method of claim 1 , wherein the transmission of a data packet by the initiating device is followed by an acknowledge (ACK) message from the following device to the initiating device on the first control line.
10. The method of claim 9 , wherein the initiating device transmits a second data packet after receipt of the ACK message from the following device.
11. The method of claim 1 , wherein generating each data packet includes generating a header for each data packet to indicate a type of control signal represented by the data packet.
12. A transmitting device comprising:
a connection to a single first control bus, the first control bus being a bi-directional, single-line bus, wherein the transmitting device is operable for coupling with a receiving device via the first control bus;
logic to convert each of one or more control signals into a data packet, each of the one or more control signals being one of a plurality of different types of control signals for a standard protocol, each data packet including a plurality of bits to be transmitted;
a transmitter, the transmitter to transmit the data packets to the receiving device on the first control bus; and
logic to arbitrate use of the first control bus, the logic to arbitrate use being operable to:
determine whether the control bus is in use by the receiving device, and
if the first control bus is not in use by the receiving device, conduct arbitration for control of the first control bus, and wherein the receiving device is a device utilizing the standard protocol and the transmitting device is a mobile device utilizing a modified protocol, the modified protocol being a modification of the standard protocol that is not included in the standard protocol.
13. The transmitting device of claim 12 , wherein the transmitter is to drive the first control bus in a bi-phase mark signaling manner.
14. The transmitting device of claim 12 , wherein transmitting the one or more data packets on the first control bus includes transmitting a sync pulse to the receiving device at the beginning of each data packet to synchronize a clock of the receiving device to a clock of the transmitting device.
15. The transmitting device of claim 12 , further comprising a switchable pull-up circuit coupled with the first control bus.
16. The transmitting device of claim 12 , wherein the standard protocol is HDMI (High-Definition Multimedia Interface).
17. The transmitting device of claim 12 , further comprising a USB-OTG (Universal Serial Bus On-The-Go) PHY (physical layer).
18. The transmitting device of claim 12 , wherein the logic to arbitrate use of the first control bus is further operable to take control of the first control bus if the transmitting device and the receiving device arbitrate use of the first control bus at the same time.
19. A receiving device comprising:
a connection to a single first control bus, the first control bus being a bi-directional, single-line bus, wherein the receiving device is operable for coupling with a transmitting device via the first control bus;
a receiver to receive one or more data packets on the first control bus, each of the one or more data packets representing one of a plurality of different types of control signals;
logic to convert each of the one or more data packets into a control signal; and
logic to arbitrate use of the first control bus, the logic to arbitrate use being operable to:
determine whether the control bus is in use by the transmitting device, and
if the first control bus is not in use by the transmitting device, conduct arbitration for control of the first control bus, and wherein the receiving device is a device utilizing the standard protocol and the transmitting device is a mobile device utilizing a modified protocol, the modified protocol being a modification of the standard protocol that is not included in the standard protocol.
20. The receiving device of claim 19 , wherein the receiver is operable to decode the one or more received data packets according to bi-phase mark encoding.
21. The receiving device of claim 19 , wherein the receiver is operable to receive a sync pulse from the transmitting device on the first control line, the receiving device to synchronize a clock of the receiving device to a clock of the transmitting device.
22. The receiving device of claim 19 , further comprising a switchable pull-down circuit coupled with the first control bus.
23. The receiving device of claim 19 , wherein the standard protocol is HDMI (High-Definition Multimedia Interface).
24. The receiving device of claim 19 , wherein the receiving device is a dual-mode device that is capable of communicating with a device utilizing the standard protocol or a device utilizing the modified protocol.
25. The receiving device of claim 19 , wherein the logic to arbitrate use of the first control bus is further operable to allow the transmitting device to take control of the first control bus if the transmitting device and the receiving device arbitrate use of the first control bus at the same time.