LAN9252SLASHML datasheet(205/329 Pages) MICROCHIP

205 / 329 page

 2015 Microchip Technology Inc.

DS00001909A-page 205

LAN9252

As shown in Table 12-3, "EtherCAT Core EEPROM Configurable Registers", bit 7 of the ASIC Configuration Register is

used to enable writes to PHY register 9 for PHYs which use this register per IEEE 802.3.

12.9.4.1

MI LINK DETECTION AND CONFIGURATION STATE MACHINE

The MI Link Detection and Configuration state machine operates as follows:

• Check that auto-negotiation is enabled

• Check that only 100BASE-X full-duplex is advertised

• Check that 1000BASE-T is not advertised

• Check that auto-negotiation is completed

• Check that link partner is 100BASE-X full-duplex

• Otherwise, set the registers as needed and restart auto-negotiation

12.9.5

ENHANCED LINK DETECTION

The EtherCAT Core supports the enhanced link detection feature with the enable is controlled by the EEPROM. With

this, the EtherCAT Core will disconnect a link if at least 32 RX errors (RX_ER) occur in a fixed interval of time (~10 us).

Refer to Section 12.8, "EEPROM Configurable Registers," on page 201 for additional information.

12.9.6

100BASE-FX SUPPORT

Since 100BASE-FX operation does not provide support for Auto-Negotiation, special consideration is required for MI

and Enhanced link detection operation.

MII LINK DETECTION

When any port is set for 100BASE-FX operation, MI link detection must be disabled by maintaining bit 2 of the MII Man-

agement Control/Status Register low.

ENHANCED LINK DETECTION

Enhanced link detection may still be enabled. If enhanced link detection detects an error condition, it will still attempt to

restart Auto-Negotiation. Since this would have no effect, the internal PHY is also reset.

A system that uses an external 100BASE-FX PHY must implement the logic described in the Enhanced FX Link Detec-

tion section of the Beckhoff PHY Selection guide to detect the restart Auto-Negotiation command and reset the external

PHY and reset / disable the external transceiver.

LAN9252/ML 数据表(PDF) 205 Page - Microchip Technology