Datasheet
Table Of Contents
- 1.0 Introduction
- 2.0 Pin Description and Configuration
- 3.0 Functional Description
- 3.1 10BASE-T/100BASE-TX Transceiver
- 3.2 RMII Interface
- 3.3 Back-to-Back Mode – 100 Mbps Copper Repeater
- 3.4 MII Management (MIIM) Interface
- 3.5 Interrupt (INTRP)
- 3.6 HP Auto MDI/MDI-X
- 3.7 Loopback Mode
- 3.8 LinkMD® Cable Diagnostic
- 3.9 NAND Tree Support
- 3.10 Power Management
- 3.11 Reference Circuit for Power and Ground Connections
- 3.12 Typical Current/Power Consumption
- 4.0 Register Descriptions
- 5.0 Operational Characteristics
- 6.0 Electrical Characteristics
- 7.0 Timing Diagrams
- 8.0 Reset Circuit
- 9.0 Reference Circuits — LED Strap-In Pins
- 10.0 Reference Clock - Connection and Selection
- 11.0 Magnetic - Connection and Selection
- 12.0 Package Outline
KSZ8081RNA/RND
DS00002199A-page 12 2016 Microchip Technology Inc.
FIGURE 3-1: AUTO-NEGOTIATION FLOW CHART
3.2 RMII Interface
The Reduced Media Independent Interface (RMII) specifies a low pin count Media Independent Interface (MII). It pro-
vides a common interface between physical layer and MAC layer devices, and has the following key characteristics:
• Pin count is 8 pins (3 pins for data transmission, 4 pins for data reception, and 1 pin for the 50 MHz reference
clock).
• 10 Mbps and 100 Mbps data rates are supported at both half- and full-duplex.
• Data transmission and reception are independent and belong to separate signal groups.
• Transmit data and receive data are each 2 bits wide, a dibit.
3.2.1 RMII SIGNAL DEFINITION
Table 3-1 describes the RMII signals. Refer to RMII Specification v1.2 for detailed information.
START AUTO-NEGOTIATION
FORCE LINK SETTING
LISTEN FOR 10BASE-T
LINK PULSES
LISTEN FOR 100BASE-TX
IDLES
ATTEMPT AUTO-
NEGOTIATION
LINK MODE SET
BYPASS AUTO-NEGOTIATION
AND SET LINK MODE
LINK MODE SET?
PARALLEL
OPERATION
NO
YES
YES
NO
JOIN FLOW