Protocol-assisted advanced low-power mode
System, methods and apparatus are described that support multimode operation of a data communication interface. A method includes receiving a first code word transmitted while a physical interface of the device is configured to operate in a low-power mode of operation, reconfiguring the physical interface in response to the first code word such that it operates in a high-speed mode, transmitting data while the physical interface operates in the high-speed mode of operation, receiving a second code word transmitted while the physical interface operated in the high-speed mode of operation, and reconfiguring the physical interface in response to the second code word, such that it operates in the low-power mode of operation. The first code word, the second code word, and the data may be transmitted in signals bound by a common voltage range. In one example, the voltage range is less than 600 millivolts.
1. A method performed in a device configured for multiple modes of data communication, comprising:
receiving a first code word transmitted while a physical interface of the device is configured to operate in a low-power mode of operation;
responsive to the first code word, reconfiguring the physical interface of the device to operate in a high-speed mode of operation;
receiving data from a multi-wire data link while the physical interface of the device is configured to operate in the high-speed mode of operation;
receiving a second code word transmitted while the physical interface of the device is configured to operate in the high-speed mode of operation; and
responsive to the second code word, reconfiguring the physical interface of the device to operate in the low-power mode of operation,
wherein the first code word, the second code word, and the data are transmitted in signals bound by a voltage range that is less than 600 millivolts.
2. The method of claim 1 , wherein the physical interface is a D-PHY interface defined by Mobile Industry Processor Interface (MIPI) Alliance specifications.
3. The method of claim 1 , further comprising:
receiving a third code word transmitted while the physical interface of the device is configured to operate in the low-power mode of operation;
responsive to the third code word, reconfiguring the physical interface of the device to operate in an ultra-low-power (ULP) mode of operation;
disabling or turning off a receiving device or circuit while the physical interface of the device is configured to operate in the ULP mode of operation;
detecting a waking signaling state of the multi-wire data link while the physical interface of the device is configured to operate in the ULP mode of operation; and
responsive to a detected waking signaling state, reconfiguring the physical interface of the device to operate in the low-power mode of operation.
4. The method of claim 3 , wherein detecting the waking signaling state of the multi-wire data link comprises:
comparing voltage levels on two wires of the multi-wire data link using a low-power differential receiver.
5. The method of claim 1 , wherein the physical interface is a C-PHY interface defined by MIPI Alliance specifications, and wherein the voltage range is defined by MIPI Alliance specifications to be no more than 250 millivolts.
6. The method of claim 1 , wherein the first code word and the second code word are self-framing.
7. The method of claim 1 , wherein the first code word is transmitted in a concatenated sequence of code words.
8. The method of claim 7 , wherein the concatenated sequence of code words includes a plurality of multi-bit words, wherein each multi-bit word includes bits configured such that shifted versions of the concatenated sequence of code words does produce an alias of another code word.
9. The method of claim 7 , wherein the concatenated sequence of code words includes a plurality of multi-bit words selected to have autocorrelation and cross-correlation properties that avoid occurrence of aliases detected in shifted versions of the concatenated sequence of code words.
10. The method of claim 1 , wherein the second code word is included in a Data End Packet, further comprising:
detecting the Data End Packet in a protocol unit; and
providing, by the protocol unit, a detection signal to the physical interface in response to detection of the Data End Packet.
11. The method of claim 10 , wherein reconfiguring the physical interface of the device to operate in the low-power mode of operation includes:
reconfiguring the physical interface in response to the detection signal.
12. An apparatus comprising:
a physical interface configurable for multiple communication modes; and
a processor configured to:
receive a first code word transmitted while the physical interface is configured to operate in a low-power mode of operation;
responsive to the first code word, reconfigure the physical interface to operate in a high-speed mode of operation;
transmit data while the physical interface is configured to operate in the high-speed mode of operation;
receive a second code word transmitted while the physical interface is configured to operate in the high-speed mode of operation; and
responsive to the second code word, reconfigure the physical interface to operate in the low-power mode of operation,
wherein the first code word, the second code word, and the data are transmitted in signals bound by a voltage range that is less than 600 millivolts.
13. The apparatus of claim 12 , wherein the physical interface is a D-PHY interface defined by Mobile Industry Processor Interface (MIPI) Alliance specifications.
14. The apparatus of claim 12 , wherein the physical interface is a C-PHY interface defined by MIPI Alliance specifications.
15. The apparatus of claim 12 , further comprising:
a low-power differential receiver adapted to compare voltage levels on two wires of a multi-wire data link when the physical interface is operated in the low-power mode of operation,
wherein the first code word is received after the low-power differential receiver detects a difference in voltage levels on the two wires of the multi-wire data link.
16. The apparatus of claim 12 , wherein the voltage range is defined by MIPI Alliance specifications to be no more than 250 millivolts.
17. The apparatus of claim 12 , wherein the first code word and the second code word are self-framing.
18. The apparatus of claim 12 , wherein the first code word is transmitted in a concatenated sequence of code words.
19. The apparatus of claim 18 , wherein the concatenated sequence of code words includes a plurality of multi-bit words, wherein each multi-bit word includes bits configured such that shifted versions of the concatenated sequence of code words does produce an alias of another code word.
20. The apparatus of claim 18 , wherein the concatenated sequence of code words includes a plurality of multi-bit words selected to have autocorrelation and cross-correlation properties that avoid occurrence of aliases detected in shifted versions of the concatenated sequence of code words.
21. A non-transitory processor readable storage medium comprising code for:
receiving a first code word transmitted while a physical interface is configured to operate in a low-power mode of operation;
responsive to the first code word, reconfiguring the physical interface to operate in a high-speed mode of operation;
transmitting data while the physical interface is configured to operate in the high-speed mode of operation;
receiving a second code word transmitted while the physical interface is configured to operate in the high-speed mode of operation; and
responsive to the second code word, reconfiguring the physical interface to operate in the low-power mode of operation,
wherein the first code word, the second code word, and the data are transmitted in signals bound by a voltage range that is less than 600 millivolts.
22. The storage medium of claim 21 , wherein the physical interface is a D-PHY interface defined by Mobile Industry Processor Interface (MIPI) Alliance specifications.
23. The storage medium of claim 21 , wherein the physical interface is a C-PHY interface defined by MIPI Alliance specifications.
24. The storage medium of claim 21 , wherein the voltage range is defined by MIPI Alliance specifications to be no more than 250 millivolts.
25. The storage medium of claim 21 , wherein the voltage range is defined by MIPI Alliance specifications to be no more than 200 millivolts.
26. The storage medium of claim 21 , wherein the first code word and the second code word are self-framing.
27. The storage medium of claim 21 , wherein the first code word is transmitted in a concatenated sequence of code words.
28. The storage medium of claim 27 , wherein the concatenated sequence of code words includes a plurality of multi-bit words, wherein each multi-bit word includes bits configured such that shifted versions of the concatenated sequence of code words does produce an alias of another code word.
29. The storage medium of claim 27 , wherein the concatenated sequence of code words includes a plurality of multi-bit words selected to have autocorrelation and cross-correlation properties that avoid occurrence of aliases detected in shifted versions of the concatenated sequence of code words.
30. An apparatus, comprising:
means for receiving code words from a multi-wire communication link, the means for receiving code words including a physical interface, wherein the code words are configured to initiate a change in communication mode of the physical interface;
means for reconfiguring the physical interface to operate in a high-speed mode of operation in response to one of the code words and for reconfiguring the physical interface to operate in a low-power mode of operation in response to another of the code words; and
means for transmitting data while the physical interface is configured to operate in the high-speed mode of operation,
wherein the code words and the data are transmitted in signals bound by a voltage range that is less than 600 millivolts.