L- and H-Tile Transceiver PHY User Guide

ID 683621
Date 12/04/2024
Public
Document Table of Contents

2.5.4.2.2. Auto-Negotiation

When auto-negotiation is required, the channels initialize at the highest supported frequency and switch to successively lower data rates if frame synchronization is not achieved. If your design requires auto-negotiation, choose a base data rate that minimizes the number of PLLs required to generate the clocks required for data transmission.

By selecting an appropriate base data rate, you can change data rates by changing the local clock generation block (CGB) divider. If a single base data rate is not possible, you can use an additional PLL to generate the required data rates.

Table 122.  Recommended Base Data Rates and Clock Generation Blocks for Available Data Rates
Data Rate (Mbps) Base Data Rate (Mbps) Local CGB Divider
1228.8 9830.4 8
2457.6 9830.4 4
3072.0 6144.0 2
4915.2 9830.4 2
6144.0 6144.0 1
8110.08 8110.08 1
9830.4 9830.4 1
10137.6 10137.6 1
12165.12 24330.24 2
24330.24 24330.24 1