Agilex™ 7 Hard Processor System Technical Reference Manual

ID 683567
Date 8/13/2024
Public
Document Table of Contents

17.7.8.2.2. Gating Off the CSR Clock in the TX LPI Mode

The following operations are performed when Bit 16 (LPIEN) of Register 12 (LPI Control and Status Register) is set: †

  1. The Transmit LPI Entry interrupt (TLPIEN bit of Register 12) is set. †
  2. The interrupt pin (sbd_intr_o) is asserted. The sbd_intr_o interrupt is cleared when the host reads the Register 12. †

After the sbd_intr_o interrupt is asserted and the MAC RX is also in the LPI mode, you can gate off the CSR clock. If the MAC RX is not in the LPI mode when you gate off the CSR clock, the events on the MAC receiver do not get reported or updated in the CSR. †

To restore the CSR clock, switch on the CSR clock when the MAC has to come out of the TX LPI mode. †

After the CSR clock is resumed, clear Bit 16 (LPIEN) of Register 12 (LPI Control and Status Register) to bring the MAC out of the LPI mode. †