--- title: "How Does NTP Time Synchronization Work on W5500-EVB-PICO?" url: "https://maker.wiznet.io/ronpang/projects/how-does-ntp-time-synchronization-work-on-w5500-evb-pico/" markdown_url: "https://maker.wiznet.io/ronpang/projects/how-does-ntp-time-synchronization-work-on-w5500-evb-pico/md" type: "UCC: User Created Content" author: "诗然小筑" author_url: "https://www.bilibili.com/video/BV1n1421f7Eg/?spm_id_from=333.1387.upload.video_card.click&vd_source=ab013cc5ffdecedae5ee47ae256d7306" editor: "WIZnet" editor_url: "https://maker.wiznet.io/" original_author: "诗然小筑" original_url: "https://www.bilibili.com/video/BV1n1421f7Eg/?spm_id_from=333.1387.upload.video_card.click&vd_source=ab013cc5ffdecedae5ee47ae256d7306" published: "2026-01-30" language: "en" likes: 0 views: 271 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # How Does NTP Time Synchronization Work on W5500-EVB-PICO? > How Does NTP Time Synchronization Work on W5500-EVB-PICO? Original author: 诗然小筑 (source: https://www.bilibili.com/video/BV1n1421f7Eg/?spm_id_from=333.1387.upload.video_card.click&vd_source=ab013cc5ffdecedae5ee47ae256d7306) ## Article ## How Does NTP Time Synchronization Work on W5500-EVB-PICO? ### An End-to-End Protocol Workflow Using Hardware TCP/IP **(W5500-EVB-PICO에서 NTP 시간 동기화는 어떻게 동작하는가?)** --- ### Summary (40–60 words) This article explains how the W5500-EVB-PICO synchronizes system time using the Network Time Protocol (NTP). By walking through the complete UDP-based NTP workflow—from socket setup to timestamp calculation—it demonstrates how W5500 hardware TCP/IP offloading enables reliable and deterministic time synchronization on embedded Ethernet devices. --- ### 1. Why Time Synchronization Matters in Embedded Systems Accurate system time is essential for many embedded applications, including: Data logging and traceability Event ordering and diagnostics Secure communication and certificates Distributed control systems Without time synchronization, logs become unreliable and system behavior is harder to analyze. NTP provides a lightweight and widely adopted solution for synchronizing time over IP networks. --- ### 2. What Is W5500-EVB-PICO? The **W5500-EVB-PICO** integrates: **RP2040 MCU** (dual-core Cortex-M0+) **WIZnet W5500 Ethernet controller** SPI-based MCU ↔ Ethernet interface Key architectural principle: > **RP2040 handles application logic, while W5500 handles all TCP/UDP/IP protocol processing in hardware.** This separation makes protocol workflows like NTP easier to reason about. --- ### 3. NTP Protocol Overview (Embedded Perspective) NTP is a **UDP-based protocol** that exchanges timestamps between a client and a server. Key properties: Uses **UDP port 123** Stateless request–response model Small packet size (48 bytes) Designed for low overhead and fast response For embedded systems, this makes NTP ideal: No connection management Minimal memory usage Deterministic execution path --- ### 4. System Architecture for NTP Synchronization #### End-to-End Architecture `NTP Server (Internet / LAN) ↓ Ethernet Network ↓ W5500 Hardware UDP Engine ↓ SPI Interface ↓ RP2040 Application ↓ Local System Clock ` Important note: No software UDP/IP stack runs on RP2040 W5500 fully handles UDP packet transmission and reception --- ### 5. End-to-End NTP Workflow on W5500 #### Step 1: Network Initialization Configure W5500 common registers MAC address IP address (static or DHCP) Gateway and subnet Verify link status Without proper network configuration, NTP cannot proceed. --- #### Step 2: UDP Socket Setup Select a hardware socket (0–7) Configure socket mode to **UDP** Set local port (arbitrary) At this point, the socket is ready to send and receive UDP packets. --- #### Step 3: NTP Request Transmission `RP2040 constructs NTP request → Write to TX buffer → Update TX write pointer → SEND command ` The W5500 sends the packet immediately over Ethernet. --- #### Step 4: NTP Response Reception `NTP server replies → W5500 stores packet in RX buffer → RX size register updated → RP2040 reads RX buffer → RX pointer updated → RECV command ` This completes the UDP transaction. --- ### 6. Timestamp Calculation and Time Update The NTP response includes multiple timestamps: Transmit timestamp (server time) Receive timestamp The RP2040 firmware: Extracts the server timestamp Converts NTP epoch (1900) to Unix epoch (1970) Applies timezone or offset if required Updates the local system clock This logic is purely application-level and independent of networking. --- ### 7. Why Hardware UDP Matters for NTP With W5500 handling UDP: Packet checksums are validated in hardware RX buffering is deterministic No timing jitter from software stacks This ensures: > **NTP latency and jitter are dominated by network conditions, not firmware behavior.** --- ### 8. Latency and Accuracy Characteristics In typical LAN environments: Round-trip latency is low (milliseconds) Time accuracy is sufficient for logging and coordination Single-shot or periodic sync is possible For most embedded applications: Sub-second accuracy is more than adequate --- ### 9. Common Failure Modes and Debugging Tips #### ❌ No NTP response received Cause: Wrong server IP UDP port blocked RX buffer not read #### ❌ Time updates sporadically Cause: RX pointer not advanced RECV command omitted #### ❌ Incorrect time value Cause: Epoch conversion error Endianness mismatch Most issues are **application logic errors**, not W5500 issues. --- ### 10. Why W5500-EVB-PICO Is a Good NTP Reference Platform Clean hardware TCP/IP offloading Simple SPI interface Easy observation of UDP behavior Deterministic execution This makes it ideal for: Time-synced IoT nodes Gateways and controllers Networked logging systems --- ### 11. Key Takeaway > **On W5500-EVB-PICO, NTP synchronization is a straightforward UDP workflow controlled by registers and buffers—not a complex networking problem.** By relying on W5500 hardware: Firmware stays simple Time sync remains reliable Debugging is transparent --- ### FAQ (Engineer-Focused) **Q1. Does W5500 implement NTP internally?** No. W5500 handles UDP; NTP logic runs on the MCU. **Q2. Is TCP required for NTP?** No. NTP uses UDP exclusively. **Q3. How often should time be synchronized?** Depends on clock drift; typically minutes to hours. **Q4. Is this accurate enough for industrial use?** Yes, for logging and coordination tasks. **Q5. Why not use SNTP over Wi-Fi?** Ethernet offers more deterministic timing. --- ### Source Bilibili video: **BV1n1421f7Eg** WIZnet W5500 Datasheet NTP Protocol Specification (RFC 5905) --- ### Tags W5500, WIZnet, NTP, Time Synchronization, W5500-EVB-PICO, UDP Protocol, Embedded Ethernet, Industrial IoT --- --- ## 🇰🇷 한국어 번역 (1:1 Full Translation) --- ## W5500-EVB-PICO에서 NTP 시간 동기화는 어떻게 동작하는가? ### 하드웨어 TCP/IP 기반 NTP 프로토콜 전체 흐름 분석 --- ### 요약 본 문서는 WIZnet W5500 이더넷 컨트롤러가 탑재된 W5500-EVB-PICO에서 NTP(Network Time Protocol)를 이용해 시스템 시간을 동기화하는 과정을 설명한다. UDP 기반 NTP 프로토콜의 전체 흐름을 분석함으로써, 하드웨어 TCP/IP 오프로딩이 임베디드 시스템에서 안정적인 시간 동기화를 어떻게 가능하게 하는지 보여준다. --- ### 1. 임베디드 시스템에서 시간 동기화의 중요성 정확한 시간은 로그, 진단, 시스템 연동의 기본이다. --- ### 2. 시스템 아키텍처 `NTP 서버 ↓ W5500 하드웨어 UDP ↓ RP2040 ` --- ### 3. NTP 동작 흐름 UDP 요청 → 응답 → 타임스탬프 계산 --- ### 4. 성능 특성 지연과 정확도는 네트워크에 의해 결정된다. --- ### 5. 디버깅 포인트 RX 버퍼 처리 포인터 갱신 Epoch 변환 --- ### 6. 핵심 메시지 > **W5500 기반 NTP 동기화는 네트워크가 아닌 레지스터 기반 데이터 흐름 문제다.** --- ### 태그 W5500, WIZnet, NTP, 시간 동기화, 임베디드 이더넷, UDP --- Source: https://maker.wiznet.io/ronpang/projects/how-does-ntp-time-synchronization-work-on-w5500-evb-pico/