Pps second pulse signal output method and system for gptp time tick on soc platform

Abstract

The invention discloses a pps second pulse signal output method for performing gptp time tick on a soc platform. The method comprises the following steps: 1, acquiring a nanosecond value of the current time; 2, calling a sleep function based on a ptp clock for sleep, and after sleep is finished, executing the step 3; 3, acquiring a nanosecond value of the current time; and 4, if the expected nanosecond value is equal to the level establishment time + / -x, outputting a level to a GPIO port of the soc chip, returning to the step 1, when the expected nanosecond value is 5000000ns, the level is a low level, and when the expected nanosecond value is 10000000ns, the level is a high level, otherwise, the level establishment time is a calibration parameter of the soc chip, and otherwise, returningto the step 3. The pps second pulse signal output method provided by the invention is realized in a software program manner, and the precision can meet the requirement, so that the signal output doesnot depend on hardware, and the application range is wide.

Description

technical field [0001] The invention relates to the technical field of gptp, in particular to a pps second pulse signal output method and system for gptp time synchronization on a soc platform. Background technique [0002] With the extensive use of the AVB protocol stack in the car, the gptp protocol (time synchronization protocol based on Ethernet) is becoming more and more important. The gptp protocol is a very important basic protocol, which provides the possibility and guarantee for all ECUs (electronic control units) in the vehicle network to use a unified time reference. In the vehicle network, there is generally one ECU as the master of the clock, and the rest of the ECUs are used as slaves to synchronize with the master. Since the synchronization accuracy of the slave determines the media synchronization quality of the avb, how to measure the synchronization accuracy and jitter of the slave is very important. The general practice in the industry is to output the s...

AI Technical Summary

Problems solved by technology

[0003] At present, the second pulse signal output of the ptp clock on the soc platform is usually realized by the logic circuit inside the soc chip, relying on related hardware implementation, the advantage is that the precision of the pps signal is high, and the disadvantage is that it is often not supported on the customer's hardware platform Output of pps signal (some soc chips do not have a corresponding pps signal output circuit inside)

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