Renesas Precision Time Protocol (PTP) Clock Manager for Linux (pcm4l) software supports IEEE 1588 and Synchronous Ethernet communication requirements. PTP Clock Manager features a clock servo and Packet Delay Variation (PDV) filter to meet the needs of ITU-T standard G.8273.4. While designed for use with the ClockMatrix™ synchronizers from Renesas, which support ITU-T standard G.8275.2, it can also be used with older generation devices. The PTP Clock Manager software is provided free of charge (under license) as long as it is paired with a clock synchronization device (such as the 8A34001) from Renesas. 

In conjunction with this software, Renesas has developed and helps maintain a PTP kernel driver in mainline Linux, creating a proven solution for managing timestamps and establishing synchronization across the network.

Combining the power of the kernel, PTP Clock Manager, and ClockMatrix™ devices, customers can easily deploy the Renesas solution with any vendor’s Time Stamp Unit (TSU) for their telecom and non-telecom applications. Many TSU vendors also offer kernel drivers in Linux, establishing a plug and play development environment.


Demand for synchronization across the internet and throughout global communications networks is increasing. At the same time, the demand for tighter and tighter synchronization is growing, and networks are adapting to support these demands. Operators are also looking to reduce costs and spur innovation by migrating to O-RAN and White Box network solutions. As new vendors enter the fray, the call for open sourced SW to support the demands of IEEE1588 and Synchronous Ethernet networks is loud. Renesas offers a compelling solution with the first such software – the Precision Time Protocol (PTP) Clock Manager for Linux.

The Linux PTP stack and clocking devices like ClockMatrix™ now give users the ability to develop non-telecom solutions that are entirely open-sourced. Having a tested, proven solution for either Grand Master or slave clock generation establishes an easy launching point for developers that significantly reduces time-to-market to allow focus on innovative, differentiated, winning solutions.

devicesTarget Devices


Title language Type Format File Size Date
Datasheets & Errata
pcm4l Datasheet Datasheet PDF 2.04 MB
User Guides & Manuals
PTP Clock Manager for Linux Message Log Manual Manual - Software PDF 363 KB
PTP Clock Manager for Linux Reference Manual Manual - Software PDF 1.77 MB
Linux PTP Using PHC Adjust Phase Quick Start Manual Manual - Software PDF 812 KB
PTP Clock Manager for Linux Management API Manual Manual - Software PDF 232 KB
pcm4l Software Quick Start Guide Manual - Software PDF 294 KB
Application Notes & White Papers
Linux PHC Infrastructure for 5G White Paper PDF 276 KB
Limiting IEEE 1588 Slave Clock Wander Caused by Packet Delay Variation White Paper PDF 975 KB
ClockMatrix Firmware Compatibility with Linux PHC Driver Application Note PDF 135 KB
Linux Kernel Support for IEEE 1588 Hardware Timestamping White Paper PDF 342 KB
pcm4l: Basic Debugging Steps for Renesas PTP Clock Manager Software v4.0.1 Application Note PDF 71 KB
pcm4l: Basic Debugging Steps for Renesas PTP Clock Manager Software v4.0.0 Application Note PDF 263 KB


Title language Type Format File Size Date
pcm4l Software Software & Tools - Software TGZ 782 KB
pcm4l Quick Start files Software & Tools - Other ZIP 132 KB