ISO 20794-4:2020

Road vehicles — Clock extension peripheral interface (CXPI) — Part 4: Data link layer and physical layer ISO 20794-4:2020

Scope

This document specifies the CXPI data link layer and the CXPI physical layer.
The DLL is based on:
— priority-based CXPI network access;
— non-destructive content-based arbitration;
— broadcast frame transfer and acceptance filtering; and
— node related error detection and error signalling.
The CXPI physical layer (PHY) requirements comprise of:
— physical signalling (PS) sub-layer, which specifies the requirements of the clock generation function, the encoding and decoding of CXPI frames, and bit-wise collision resolution logic;
— physical media attachment (PMA) sub-layer, which specifies the requirements of the signal shaping waveform logic;
— physical media dependent (PMD) sub-layer, which specifies the requirements of the CXPI network termination, electrostatic discharge protection, etc., and device connector requirements; and
— physical media (PM), which specifies the requirements of the CXPI network cable/wiring harness.