Integration
Table 14-8. RGMII Interface Signal Descriptions
Signal
Type
Description
The transmit data pins are a collection of 4 bits of data. RGMII_RD0 is the least-
RGMII_TD[3-0]
O
significant bit (LSB).
The signals are valid only when RGMII_TCTL is asserted.
Transmit Control/enable .The transmit enable signal indicates that the RGMII_TD
RGMII_TCTL
O
pins are generating data for use by the PHY.
The transmit reference clock will be 125Mhz, 25Mhz, or 2.5Mhz depending on
RGMII_TCLK
O
speed of operation.
The receive data pins are a collection of 4 bits of data. RGMII_RD is the least-
RGMII_RD[3-0]
I
significant bit (LSB).
The signals are valid only when RGMII_RCTL is asserted.
The receive data valid/control signal indicates that the RGMII_RD pins are nibble
RGMII_RCTL
I
data for use by the 3PSW.
The receive clock is a continuous clock that provides the timing reference for
receive operations.The clock is generated by the PHY and is 2.5 MHz at 10
RGMII_RCLK
I
Mbps operation and 25 MHz at 100 Mbps operation,125 MHz at 1000Mbps of
operation.
Management data clock. The MDIO data clock is sourced by the MDIO module
MDIO_CLK
O
on the system. It is used to synchronize MDIO data access operations done on
the MDIO pin.
MDIO DATA. MDIO data pin drives PHY management data into and out of the
PHY by way of an access frame consisting of start of frame, read/write
MDIO_DATA
I/O
indication,PHY address, register address, and data bit cycles. The MDIO_DATA
pin acts as an output for all but the data bit cycles at which time it is an input for
read operations.
1175
SPRUH73H – October 2011 – Revised April 2013
Ethernet Subsystem
Copyright © 2011–2013, Texas Instruments Incorporated