KSZ8091MNX Datasheet, PDF (39/83 Pages) Micrel Semiconductor – 10Base-T/100Base-TX Physical Layer Transceiver

Micrel, Inc.
KSZ8091MNX/KSZ8091RNB
Transmit Direction Control (MAC-to-PHY)
The KSZ8091MNX enters LPI mode for the transmit direction when its attached EEE-compliant MII MAC de-asserts
TXEN, asserts TXER, and sets TXD[3:0] to 0001. The KSZ8091MNX remains in the LPI transmit state while the MAC
maintains the states of these signals. When the MAC changes any of the TXEN, TXER, or TX data signals from their LPI
state values, the KSZ8091MNX exits the LPI transmit state.
The TXC clock is not stopped, because it is sourced from the PHY and is used by the MAC for MII transmit.
Figure 11 shows the LPI transition for MII (100Mbps) transmit.
Figure 11. LPI Transition – MII (100Mbps) Transmit
Similarly, the KSZ8091RNB enters LPI mode for the transmit direction when its attached EEE-compliant RMII MAC de-
asserts TXEN and sets TXD [1:0] to 01. The KSZ8091RNB remains in the LPI transmit state while the RMII MAC
maintains the states of these signals. When the RMII MAC changes any of the TXEN or TX data signals from their LPI
state values, the KSZ8091RNB exits the LPI transmit state.
Figure 12 shows the LPI transition for RMII (100Mbps) transmit.
Figure 12. LPI Transition – RMII (100Mbps) Transmit
August 31, 2015
39
Revision 1.2