BS ISO 20794-4:2020

This standard BS ISO 20794-4:2020 Road vehicles. Clock extension peripheral interface (CXPI) is classified in these ICS categories:

• 43.040.15 Car informatics. On board computer systems

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.