Gateway, nodes, and method for a vehicle
A gateway for a vehicle communication system is configured to forward a payload message from a first node of a first fieldbus system to a second node of a second fieldbus system, wherein the first and the second fieldbus systems are different. The gateway is configured to synchronize a first clock in the first node with a second clock in the second node.
1. A component of a communication system in a vehicle having two or more fieldbus systems, comprising:
a gateway coupled to the two or more fieldbus systems, wherein the gateway is programmed to:
forward a payload message from a first node of a first fieldbus system to a second node of a second fieldbus system, the first and second fieldbus systems being different types of bus systems;
synchronize a first clock in the first node of the first fieldbus system with a second clock in the second node of the second fieldbus system;
generate a timestamp on a basis of a reference time, wherein the timestamp corresponds to a generation time of the timestamp;
transmit the timestamp in a first message according to a first protocol of the first fieldbus system to the first node of the first fieldbus system; and
transmit the timestamp in a second message according to a second protocol of the second fieldbus system to the second node, wherein the first and second protocols are different.
2. The component according to claim 1 , wherein the gateway is coupled to a serial asynchronous fieldbus system as the first fieldbus system and a serial synchronous fieldbus system as the second fieldbus system.
3. The component according to claim 2 , wherein the first fieldbus system is a CAN fieldbus system and the second fieldbus system is a FlexRay fieldbus system.
4. The component according to claim 1 , wherein the gateway is further programmed to:
generate the timestamp as a segment from a Precision Time Protocol (PTP) timestamp.
5. The component according to claim 4 , wherein the timestamp is generated from a nanosecondsField of the PTP timestamp.
6. The component according to claim 5 , wherein:
the timestamp has a maximum measurable time period; and
the maximum measurable time period corresponds to or exceeds a transit time of payload messages from the first node to the second node.
7. The component according to claim 6 , wherein the gateway is further programmed to:
transmit the second message in a predefined time window of the second bus system; and
determine the timestamp such that the timestamp corresponds to a time of the predefined time window.
8. The component according to claim 7 , wherein the gateway is further programmed to:
receive the reference time from a GPS receiver or an instrument cluster of the vehicle.
9. The component according to claim 1 , wherein:
the timestamp has a maximum measurable time period; and
the maximum measurable time period corresponds to or exceeds a transit time of payload messages from the first node to the second node.
10. The component according to claim 1 , wherein the gateway is further programmed to:
transmit the second message in a predefined time window of the second bus system; and
generate the timestamp such that the timestamp corresponds to a time within the predefined time window within which the second message is to be transmitted.
11. The component according to claim 1 , wherein the gateway is further programmed to:
receive the reference time from a GPS receiver or an instrument cluster of the vehicle.
12. The component according to claim 1 , wherein the gateway is further programmed to:
synchronize the first clock in the first node with the second clock in the second node using a Precision Time Protocol method.
13. A node of a CAN bus system in a vehicle, the node comprising:
a clock that generates a timestamp with a predefined measurable time period and a predefined time resolution; and
a control unit coupled with the clock that provides a payload to be transmitted over the CAN bus system with a payload timestamp.
14. The node according to claim 13 , wherein the payload timestamp has a shortened measurable time period as the predefined measurable time period and/or has an increased time resolution as the predefined time resolution.
15. A method for synchronizing a synchronous bus system of a vehicle with an asynchronous bus system of the vehicle, the method comprising the acts of:
generating a timestamp on a basis of a reference time, wherein the timestamp corresponds to a generation time of the timestamp;
determining a time interval between said timestamp and a transit time window of the synchronous bus system;
correcting the timestamp using the determined time interval; and
transmitting a message over the synchronous bus system with the corrected time stamp within the transit time window.
16. The method according to claim 15 , wherein the method synchronizes the time in an asynchronous bus system by transmitting a further message with the timestamp and the time interval in the asynchronous bus system, the asynchronous bus system being different from the synchronous bus system.