System and method of sending data via additional secondary data lines on a bus
A serial low-power inter-chip media bus communications link is deployed in apparatus having multiple Integrated Circuit devices. Communications capabilities of a device coupled to the communications link may be determined and configuration or framing message may be sent to the first device based on the capabilities. The messages may be transmitted on a primary data line of the communications link with a clock used to control timing of transmission on at least the primary data line. The communications capabilities can include information identifying a number of data wires supported by or coupled to the device. A first device may be configured to communicate with a second device over a secondary data line, which may be reserved for such direct communication. Communications on the secondary data line may be synchronized using the clock signal and may be controlled by a different protocol than the protocol used for the primary data line.
1. A communications method, comprising:
transmitting one or more bus management messages to a plurality of devices over a two-wire shared serial bus in accordance with a common protocol, the common protocol being supported by each of the plurality of devices;
determining that a first device in the plurality of devices is coupled to a number of additional data wires, including one or more secondary data lines that couple the first device and a second device in the plurality of devices; and
sending a configuration message to the first device over a primary data line provided by the shared serial bus, wherein the shared serial bus includes a clock line that carries a clock signal that controls timing of transmission of the configuration message,
wherein the configuration message includes information configured to cause the first device to communicate with the second device in accordance with a first I3C protocol adapted to transmit data using the one or more secondary data lines.
2. The method of claim 1 , wherein the common protocol comprises an I2C protocol.
3. The method of claim 1 , wherein the first device is configured to communicate with the second device over the shared serial bus using a second I3C protocol while communicating with the second device over the one or more secondary data lines in accordance with the first I3C protocol, and wherein the second I3C protocol is different from the first I3C protocol.
4. The method of claim 1 , wherein communication using the one or more secondary data lines is synchronized to the clock signal.
5. The method of claim 1 , further comprising:
allocating a plurality of communications channels provided using the primary data line and the one or more secondary data lines.
6. The method of claim 1 , wherein at least one of the additional data wires connects the first device with the second device using a protocol other than an I3C protocol.
7. The method of claim 1 , wherein the first device is configured to communicate with the second device over the shared serial bus using an I3C single data rate or double data rate protocol.
8. The method of claim 1 , wherein data is encoded in symbols for transmission using the shared serial bus and the one or more secondary data lines, and in accordance with an I3C high data rate protocol.
9. The method of claim 1 , further comprising:
sending one or more additional messages over the primary data line to the plurality of devices when the shared serial bus is operated in accordance with an I2C protocol; and
transmitting a reconfiguration command to the plurality of devices,
wherein the reconfiguration command causes each of the plurality of devices to adopt a configuration in accordance with the one or more additional messages.
10. The method of claim 9 , wherein the first device is configured to relay the one or more additional messages to a third device.
11. An apparatus, comprising:
a communication interface configured to couple the apparatus to a plurality of devices over a two-wire shared serial bus, wherein each of the plurality of devices is operable to communicate over the shared serial bus in accordance with a common protocol, and wherein the plurality of devices includes a first device and a second device;
a bus interface; and
a processing circuit configured to:
transmit one or more bus management messages to the plurality of devices over the shared serial bus in accordance with the common protocol;
determine that the first device is coupled to a number of additional data wires, including one or more secondary data lines that couple the first device to the second device; and
send a configuration message to the first device over a primary data line-provided by the shared serial bus, wherein the shared serial bus includes a clock line that carries a clock signal that controls timing of transmission of the configuration message,
wherein the configuration message includes information configured to cause the first device to communicate with the second device in accordance with a first I3C protocol adapted to transmit data using the one or more secondary data lines.
12. The apparatus of claim 11 , wherein the common protocol comprises an I2C protocol.
13. The apparatus of claim 11 , wherein the first device is configured to communicate with the second device over the shared serial bus using a second I3C protocol while communicating with the second device over the one or more secondary data lines in accordance with the first I3C protocol, and wherein the second I3C protocol is different from the first I3C protocol.
14. The apparatus of claim 11 , wherein communication using the one or more secondary data lines is synchronized to the clock signal.
15. The apparatus of claim 11 , wherein the processing circuit is further configured to:
allocate a plurality of communications channels provided using the primary data line and the one or more secondary data lines.
16. The apparatus of claim 11 , wherein at least one of the additional data wires connects the first device with the second device using a protocol other than an I3C protocol.
17. The apparatus of claim 11 , wherein the first device is configured to communicate with the second device over the shared serial bus using an I3C single data rate or double data rate protocol.
18. The apparatus of claim 11 , wherein data is encoded in symbols for transmission using the shared serial bus and the one or more secondary data lines, and in accordance with an I3C high data rate protocol.
19. The apparatus of claim 11 , wherein the processing circuit is further configured to:
send one or more additional messages over the primary data line to the plurality of devices when the shared serial bus is operated in accordance with an I2C protocol; and
transmit a reconfiguration command to the plurality of devices,
wherein the reconfiguration command causes each of the plurality of devices to adopt a configuration in accordance with the one or more additional messages.
20. The apparatus of claim 19 , wherein the first device is configured to relay the one or more additional messages to a third device.
21. A communications method, comprising:
receiving one or more bus management messages from a two-wire shared serial bus, wherein the one or more bus management messages are received in accordance with an I2C protocol;
reconfiguring a bus interface in response to the one or more bus management messages;
communicating with a first device in accordance with a first I3C protocol using the shared serial bus after reconfiguring the bus interface; and
communicating with a second device over one or more secondary data lines in accordance with a second I3C protocol after reconfiguring the bus interface,
wherein the first device is restricted from communicating over the one or more secondary data lines.
22. The method of claim 21 , further comprising:
communicating with the second device over the shared serial bus using a third I3C protocol while communicating with the second device over the one or more secondary data lines, wherein the third I3C protocol is different from the second I3C protocol.
23. The method of claim 21 , wherein communicating with the second device comprises:
encoding data in a sequence of symbols in accordance with an I3C high data rate protocol; and
using the shared serial bus and the one or more secondary data lines to transmit the sequence of symbols.
24. The method of claim 21 , wherein the first I3C protocol comprises an I3C single data rate or an I3C double data rate protocol.
25. The method of claim 21 , further comprising:
reporting communications capabilities information to a manager in the first device, wherein the one or more bus management messages are generated in response to the communications capabilities information.
26. An apparatus, comprising:
a bus interface configured to couple the apparatus to a two-wire shared serial bus in accordance with a plurality of protocols; and
a processing circuit configured to:
receive one or more bus management messages from the shared serial bus, wherein the one or more bus management messages are received in accordance with an I2C protocol;
reconfigure the bus interface in response to the one or more bus management messages;
communicate with a first device in accordance with a first I3C protocol using the shared serial bus after reconfiguring the bus interface; and
communicate with a second device over one or more secondary data lines in accordance with a second I3C protocol after reconfiguring the bus interface,
wherein the first device is restricted from communicating over the one or more secondary data lines.
27. The apparatus of claim 26 , wherein the processing circuit is further configured to:
communicate with the second device over the shared serial bus using a third I3C protocol while communicating with the second device over the one or more secondary data lines, wherein the third I3C protocol is different from the second I3C protocol.
28. The apparatus of claim 26 , wherein the processing circuit is further configured to communicate with the second device by:
encoding data in a sequence of symbols in accordance with an I3C high data rate protocol; and
using the shared serial bus and the one or more secondary data lines to transmit the sequence of symbols.
29. The apparatus of claim 26 , wherein the first I3C protocol comprises an I3C single data rate or an I3C double data rate protocol.
30. The apparatus of claim 26 , wherein the processing circuit is further configured to:
report communications capabilities information to a manager in the first device, wherein the one or more bus management messages are generated in response to the communications capabilities information.