Texas Instruments THUNDERSWITCH II TNETX4090 - Manual (Page 8)

TNETX4090
ThunderSWITCH II

9-PORT 100-/1000-MBIT/S ETHERNET

SWITCH
SPWS044E – DECEMBER 1997 – REVISED AUGUST 1999
8
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
Terminal Functions (Continued)
100-/1000-Mbit/s MAC interface (GMII mode)
TERMINAL
NAME
I/O
INTERNAL
RESISTOR†
DESCRIPTION
M08_COL I Pulldown
Collision sense. Assertion of M08_COL during half-duplex operation indicates network collision.
Additionally, during full-duplex operation, transmission of new frames does not commence if this
terminal is asserted.
M08_CRS I Pulldown Carrier sense. M08_CRS indicates a frame carrier signal is being received.
M08_EWRAP O None Enable wrap. M08_EWRAP reflects the state of the loopback bit in the PCS8Control register.
M08_GTCLK O None Transmit clock. Transmit clock output to attached physical layer (PHY) device.
M08_LINK I Pulldown
Connection status. M08_LINK indicates the presence of port connection.
– If M08_LINK = 0, there is no link.
– If M08_LINK = 1, the link is OK.
M08_LREF O None
Renegotiate. M08_LREF indicates to the attached PHY device that this device wishes to negotiate
a new configuration.
– Following a 0-to-1 transition of neg in PortxControl, M08_LREF is asserted low, and
remains low until M08_LINK goes low. If M08_LINK was already low, M08_LREF is still
activated for at least one cycle.
– M08_LREF is asserted low for as long as initd in SysControl = 0, regardless of the state
of M08_LINK.
M08_RCLK I Pullup Receive clock. Receive clock source from the attached PHY.
M08_RFCLK I Pullup
Reference clock. Reference clock, used as the clock source for the transmit side of this port and
to generate M08_GTCLK.
M08_RXD7
M08_RXD6
M08_RXD5
M08_RXD4
M08_RXD3
M08_RXD2
M08_RXD1
M08_RXD0
I Pullup
Receive data. Byte receive data from the attached PHY. When M08_RXDV is asserted, these
signals carry receive data. Data on these signals is synchronous to M08_RCLK.
M08_RXDV I Pulldown
Receive data valid. M08_RXDV indicates data on M08_RXD7–M08_RXD0 is valid. This signal is
synchronous to M08_RCLK.
M08_RXER I Pulldown Receive error. M08_RXER indicates reception of a coding error on received data.
M08_TXD7
M08_TXD6
M08_TXD5
M08_TXD4
M08_TXD3
M08_TXD2
M08_TXD1
M08_TXD0
O None
Transmit data. Byte transmit data. When M08_TXEN is asserted, these signals carry transmit data.
Data on these signals is synchronous to M08_GTCLK.
M08_TXEN O None
Transmit enable. M08_TXEN indicates valid transmit data on M08_TXD7–M08_TXD0. This signal
is synchronous to M08_GTCLK.
M08_TXER O None
Transmit error. M08_TXER allows coding errors to be propagated between the media-access
control (MAC) and the attached PHY. It is asserted at the end of an under-running frame, enabling
the device to force a coding error.
† Internal resistors are provided to pull signals to known values. The system designers should determine if additional pullups or pulldowns are
required in their systems.