Intel® Stratix® 10 Hard Processor System Technical Reference Manual

ID 683222
Date 11/28/2022
Public

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17.7.8.2.1. Gating Off the CSR Clock in the RX LPI Mode

The following operations are performed when the MAC receives the LPI pattern from the PHY. †

  1. The MAC RX enters the LPI mode and the RX LPI entry interrupt status [RLPIEN interrupt of Register 12 (LPI_Control_Status)] 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 (LPI_Control_Status). †

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

For restoring the CSR clock, wait for the LPI exit indication from the PHY after which the MAC asserts the LPI exit interrupt on lpi_intr_o (synchronous to clk_rx_i). The lpi_intr_o interrupt is cleared when Register 12 is read. †