TX
RX
RECEIVE BLOCK
10BASE-T and
100BASE-TX
TRANSMIT BLOCK
10BASE-T and
100BASE-TX
PHY
Registers
Auto-
Negotiation
State Machine
Clock
Generation
DAC
ADC
Auto MDIX
LED Drivers
Cable
Diagnostics
Serial
Management
Interface
EN0MDIO
EN0MDC
EN0TXOP /
EN0TXON
EN0RXIP /
EN0RXIN
EN0LEDn
Extended PHY
Registers
25 MHz MOSC
Ethernet PHY
930
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Ethernet Controller
•
Programmable Fast Link Down Modes
•
Auto-MDIX for 10/100Mbs
•
Energy Detection Mode
•
Serial Management Interface
•
IEEE 802.3u Auto-Negotiation and Parallel Detection
•
IEEE 802.3u ENDEC, 10Base-T Transceivers and Filters
•
IEEE 802.3u PCS, 100Base-TX Transceivers
•
Integrated ANSI X3.263 Compliant TP-PMD Physical Sublayer with Adaptive Equalization and
Baseline Wander Compensation
•
Three programmable LEDs that support detection of Link OK, 10/100Mbs activity, TX/RX transfers,
collisions and full duplex mode
15.4.1 Integrated PHY Block Diagram
shows the internal PHY integration. Note that the reference clock input comes from an
external 25 MHz ±50 ppm crystal or oscillator connected to the MOSC signals.
Figure 15-14. Integrated PHY Diagram
15.4.2 Functional Description
The following sections describe the functional characteristics of the integrated PHY.
15.4.2.1 Auto-Negotiation
The Ethernet PHY can auto-negotiate to operate in 10Base-T or 100Base-TX. When the Ethernet PHY is
enabled or on the deassertion of software reset, the Ethernet MAC Peripheral Configuration Register
(EMACPC) register, offset 0xFC4, is configured such that auto-negotiation is enabled and the auto
negotiation mode (ANMODE) bit field is programmed to 10Base-T, Half/Full-Duplex 100Base-TX,
Half/Full-Duplex. With auto-negotiation enabled, the PHY negotiates with the link partner to determine the
speed and duplex mode with which to operate. If the link partner is unable to auto-negotiate, the PHY
goes into parallel-detect mode to determine the speed of the link partner. Under parallel-detect mode, the
duplex mode is fixed at half-duplex. The PHY supports four different Ethernet protocols (10Mbs Half-
Duplex, 10Mbs Full-Duplex, 100Mbs Half-Duplex, and 100Mbs Full-Duplex). Auto-Negotiation selects the