The IEEE 1588 standard envisages adding timing synchronization to the Ethernet network's networking design, which is typically used for data communications and wireless base stations to synchronize timing over the network. Now, synchronous networks are in a wide range of industries and power generation The market is becoming increasingly popular. Programmable logic controllers (PLCs), brushless motors, robots, synchrophasors, assembly line control and other areas are seeking to use IEEE 1588 synchronous timing program.
The timing accuracy of a design depends on the design requirements and the connected network.The reason why the IEEE 1588 becomes complex is that the accuracy and accuracy of any IEEE 1588 design depends on many factors, including the type of network configuration, the number of nodes And other features of the network. In general, the more IEEE 1588 sensing points on the network, the more accurate the timing. To help with timing accuracy, the IEEE 1588 standard establishes a number of profiles to help improve timeliness accuracy. For example, the power profile is used to support power distribution applications, and when a design is implemented, the appropriate profile must be supported.
The IEEE 1588 network can consist of Ethernet switches, gateways and access points, and master / slave / client endpoint devices. Only a single Ethernet port is required for the master / slave endpoint. Most industrial devices that require IEEE1588, such as Smart Grid relays only Need a Ethernet port.Although the master / slave device only needs a port, but in the design to increase IEEE 1588 is not easy.
In the IEEE 1588 design need to implement the following four key functions:
Support the timestamp through the Ethernet PHY or other device; the required profile must be included in the software program running by the processor; an algorithm running in the software program must be able to be adjusted according to the IEEE 1588 profile output PLL; can be dynamically adjusted to output the network timing clock PLL. Figure 1 is a complete IEEE1588 solution block diagram.
You can use a variety of design methods to implement the IEEE 1588. For example, if your design already has a main processor and operating system (OS), will you integrate the profile software program with your other software code Is the OS running OS running your profile program or does you use a low-level processor to implement the entire solution as described in Figure 1?
Of course, adding a profile software to an existing host processor does not increase component costs, but increases the cost of software engineering. If an existing OS has an applicable profile, it must also ensure that the IEEE 1588 program is running at The various interrupts of the main processor and the main processor do not cause the program to fail because the software engineer usually does not understand the critical response time of the profile, so this is an easy challenge.
The alternative is to use a dedicated external processor for the entire solution, although this increases the board cost and may increase the board area, but there are several significant benefits to doing so.
First, there is no need for expensive software integration and verification. With an external processor, verification will be significantly reduced, and there is a time to market advantage. In addition, if the dedicated processor has proven to be running IEEE 1588 profiles, Then the performance can be guaranteed.Finally, the use of dedicated processor, because only need to verify the IEEE 1588 profile software, without having to verify the main processor and OS software, so the site update faster.
There are a number of trade-offs that need to be considered when implementing a single port IEEE 1588 master / client design, and users should consider the professional and technical capabilities that can be supported within the company. If the user's organization is very knowledgeable about IEEE 1588, The integrated software may be the right choice, and for IEEE 1588 users who are not deep enough, an external processor that provides a complete solution should be used.