24 www.xilinx.com Embedded Tri-Mode Ethernet MAC User Guide
UG074 (v2.2) February 22, 2010
Chapter 2: Ethernet MAC Architecture
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Flow Control Client-Side Interface Signals
Table 2-3 describes the signals used by the client to request a flow control action from the
transmit engine. The flow control block is designed per the specifications in Clause 31 of
the IEEE Std 802.3-2002 standard. Flow control frames received by the Ethernet MAC are
automatically handled.
EMAC#CLIENTRXDVLDMSW Output
This signal denotes an odd number of bytes in the receive data
path when the width of EMAC#CLIENTRXD is set to 16 bits
wide.
In a frame with an odd number of bytes, the
EMAC#CLIENTRXD[7:0] byte is valid on the last byte.
When the width of EMAC#CLIENTRXD is set to 8 bits wide, this
signal should be left unconnected.
EMAC#CLIENTRXGOODFRAME Output
This signal is asserted after the last receipt of data to indicate the
reception of a compliant frame.
EMAC#CLIENTRXBADFRAME Output
This signal is asserted after the last receipt of data to indicate the
reception of a non-compliant frame.
EMAC#CLIENTRXSTATS[6:0] Output
The statistics data on the last received data frame. The 27-bit raw
RX statistics vector is multiplexed into a seven-bits per RX clock
cycle output for statistics gathering. See “Receiver Statistics
Vector” in Chapter 3.
EMAC#CLIENTRXSTATSBYTEVLD Output
Asserted if an Ethernet MAC frame byte (including destination
address to FCS) is received. Valid on every RX clock cycle.
EMAC#CLIENTRXSTATSVLD Output
Asserted by the Ethernet MAC after the end of receiving a frame
to indicate a valid EMAC#CLIENTRXSTATS[6:0] output.
EMAC#CLIENTRXCLIENTCLKOUT Output See “Receive Clocking Scheme” in Chapter 5.
EMAC#CLIENTRXDVREG6 Output Reserved - not used.
Table 2-2: Receive Client Interface Signals (Cont’d)
Signal Direction Description
Table 2-3: Flow Control Interface Signals
Signal Direction Description
CLIENTEMAC#PAUSEREQ Input Asserted by client to transmit a pause frame.
CLIENTEMAC#PAUSEVAL[15:0] Input
The amount of pause time for the transmitter as defined in the
IEEE Std 802.3-2002 specification.
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