How to run IEEE-1588 on Raspberry Pi hardware?

 IEEE-1588 (Precision Time Protocol, PTP) provides sub-microsecond clock synchronization for networked devices. Here's how to implement it on Raspberry Pi:



1. Hardware Requirements

  • Raspberry Pi 4/5 (recommended) or Pi 3B+

  • Ethernet connection (PTP works best with wired networking)

  • Optional: GPS module (for grandmaster clock functionality)


2. Software Setup

Install Required Packages

bash

sudo apt update
sudo apt install linuxptp ethtool

Configure Network Interface

Check your Ethernet interface name:

bash

ip a

(typically eth0 for wired connections)

Enable hardware timestamping (if supported):

bash

sudo ethtool -T eth0

Look for:


Hardware Transmit Timestamping: yes
Hardware Receive Timestamping: yes

If supported, enable PTP features:

bash

sudo ethtool --set-ts eth0 rx-filter ptpv2


3. Running PTP

Option A: Ordinary Clock (Slave)

bash

sudo ptp4l -i eth0 -m -S

  • -i: Interface

  • -m: Print messages to stdout

  • -S: Software timestamping (use -H for hardware if available)

Option B: Grandmaster Clock

If you want your Pi to act as the time source:

bash

sudo ptp4l -i eth0 -m -S --master_only 1

Monitor Synchronization

bash

sudo pmc -u -b 0 'GET TIME_STATUS_NP'


4. Hardware Timestamping (Pi 4/5 Only)

For best accuracy (sub-100ns):

bash

# Load module for hardware timestamping
sudo modprobe ptp_rpi
sudo ptp4l -i eth0 -m -H -f /etc/linuxptp/ptp4l.conf


5. System Time Synchronization

To sync PTP with system clock:

bash

sudo phc2sys -s eth0 -c CLOCK_REALTIME -O 0 -m


6. Verification

Check offset from master:

bash

sudo ptp4l -i eth0 -m -q -S


7. Autostart Configuration

Create a service file:

bash

sudo nano /etc/systemd/system/ptp.service

Add:


[Unit]
Description=PTP Service

[Service]
ExecStart=/usr/sbin/ptp4l -i eth0 -m -H -f /etc/linuxptp/ptp4l.conf
Restart=always

[Install]
WantedBy=multi-user.target

Then enable:

bash

sudo systemctl enable ptp
sudo systemctl start ptp


8. Expected Performance

  • Software timestamping: ±100μs accuracy

  • Hardware timestamping (Pi 4/5): ±100ns accuracy

  • With GPS grandmaster: ±50ns accuracy


Troubleshooting

  • If ptp4l fails, check kernel messages: dmesg | grep ptp

  • Ensure NTP is disabled: sudo timedatectl set-ntp false

  • For industrial applications, consider a dedicated PTP grandmaster clock

This setup turns your Raspberry Pi into a precise network time client or server, suitable for audio/video synchronization, industrial automation, or financial timestamping applications.

评论

发表评论

此博客中的热门博文

What is a DSP? (Digital Signal Processor)

图片
 A DSP ( Digital Signal Processor ) is a specialized microprocessor or an integrated circuit (IC) designed to process digital signals efficiently and in real-time . DSPs are optimized for mathematical computations like additions, subtractions, multiplications, and divisions, making them ideal for applications that involve audio, video, radar, communications, and sensor data processing . Key Functions of DSPs Signal Filtering: Remove noise or unwanted frequencies from signals. Data Compression: Compress audio and video signals for transmission or storage. Modulation/Demodulation: Encode and decode signals for communication systems. Fourier Transform (FFT): Analyze signals in the frequency domain. Control Systems: Real-time control in robotics and industrial automation. How DSPs Work Analog-to-Digital Conversion (ADC): Converts analog signals (e.g., sound or temperature) into digital form. Digital Signal Processing: Performs mathematical operations on digital data (e.g., f...
阅读全文

How To Connect Stm32 To PC?

图片
Connecting an STM32 microcontroller to a PC typically involves using a communication interface such as USB , UART (serial) , SPI , or I2C . The most common and straightforward method is through USB or UART . Below, I’ll explain how to connect your STM32 to a PC using these methods. Method 1: Using USB (Direct Connection via Virtual COM Port) Many STM32 boards, such as the STM32 Nucleo or STM32 Discovery series, have a built-in USB-to-serial interface, which allows you to communicate with your PC via a virtual COM port . Steps for Connecting via USB: Use a USB Cable : If your STM32 board has a built-in USB interface (e.g., STM32 Nucleo boards ), simply use a micro-USB or USB-C cable to connect the board to your PC. Install Drivers (if required) : Some STM32 boards (e.g., those with ST-Link or USB to UART interfaces) might require drivers to be installed on your PC. Visit the STMicroelectronics website and download the appropriate ST-Link drivers or Virtual COM Port (VCP) dri...
阅读全文

MCU clock configuration and external crystal oscillator selection

图片
  Configuring the clock source for a microcontroller ( MCU ) is a critical step in embedded system design, as it directly impacts the performance, power consumption, and reliability of the system. The clock source can be internal (e.g., an RC oscillator) or external (e.g., a crystal oscillator). Below is a detailed guide on   MCU clock configuration   and   external crystal oscillator selection : 1. Clock Sources for MCUs MCUs typically support multiple clock sources, which can be categorized as: Internal Clock Sources RC Oscillator : Low-cost and integrated into the MCU. Lower accuracy (±1% to ±10%). Suitable for applications where precise timing is not critical. PLL (Phase-Locked Loop) : Multiplies the frequency of an internal or external clock. Provides higher frequencies for high-performance applications. External Clock Sources Crystal Oscillator : High accuracy (±10 ppm to ±100 ppm). Requires external crystal and load capacitors. Ideal for applications requirin...
阅读全文