CAN FD (Controller Area Network Flexible Data-Rate) is the high-performance evolution of the classical CAN bus.
CAN FD (控制器區域網路靈活數據速率) 是傳統 CAN 總線的高性能演進版本。
Key Differences: CAN vs. CAN FD | 主要差異：CAN 與 CAN FD
As requested, here is a comparison of the two standards using metric-friendly terminology:
根據您的要求，以下是這兩種標準的比較表：
| Feature 特性 | Classical CAN 傳統 CAN | CAN FD |
| Data Payload 數據負載 | Up to 8 bytes | Up to 64 bytes |
| Max Speed 最大速度 | 1 Mbps | 5 to 8 Mbps (in data phase) |
| Topology 拓撲結構 | Multi-master (Linear) | Multi-master (Linear) |
| Backward Compatibility 向後相容性 | N/A | CAN FD nodes can read Classical CAN |
| Efficiency 效率 | Lower (high overhead) | Higher (more data per frame) |
Why use CAN FD? | 為什麼要使用 CAN FD？
Increased Bandwidth (頻寬增加): By increasing the bit rate during the "data phase" and extending the payload from 8 to 64 bytes, it can transmit significantly more data without increasing the physical wiring.
透過在「數據階段」提高位元速率並將負載從 8 位元組擴展到 64 位元組，它可以在不增加實體佈線的情況下傳輸更多數據。
Reduced Latency (降低延遲): Larger frames mean fewer messages are needed to send long data streams, reducing the "wait time" on the bus.
更大的數據幀意味著發送長數據流所需的訊息更少，從而減少了總線上的「等待時間」。
Future-Proofing (面向未來): Essential for modern automotive features like ADAS (Advanced Driver Assistance Systems) and firmware-over-the-air (FOTA) updates.
對於自動駕駛輔助系統 (ADAS) 和韌體雲端更新 (FOTA) 等現代汽車功能至關重要。
Technical Note | 技術筆記
In a CAN FD frame, the speed increases only during the Data Phase. The Arbitration Phase (where nodes decide who speaks first) still runs at the standard speed (usually 500 kbps or 1 Mbps) to ensure stability across the cable length.
在 CAN FD 幀中，速度僅在數據階段增加。仲裁階段（節點決定誰先發言）仍以標準速度（通常為 500 kbps 或 1 Mbps）運行，以確保整個電纜長度的穩定性。
