Arria® 10 Transceiver PHY User Guide

ID 683617
Date 4/01/2024
Document Table of Contents

7.2.6. Rate Switch Flag Register

The rate switch flag is for CDR charge pump calibration. Each SOF has CDR default charge pump settings. After power up, these settings are loaded into the PreSICE memory space. If you change the line rate, it may require new charge pump settings, which are stored into the Avalon® memory-mapped interface reconfiguration register space. During RX PMA calibration (including CDR), PreSICE needs to know which set of CDR charge pump setting to use.

If you set 0x166[7] = 0x1, PreSICE assumes the setting in its memory space is still valid. If after a rate change you set 0x166[7]=0x0, PreSICE uses the setting from the Avalon® memory-mapped interface reconfiguration register uploaded from the dynamic reconfiguration interface or MIF streamed in. After calibration, 0x166[7] = 0x1 is set automatically and PreSICE uses the settings in its memory space. The rate switch flag only tells PreSICE where to obtain the CDR charge pump