
VIA Technologies, Inc.
Preliminary VT6516 Datarsheet
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30-
3.1.4 Network interface
The VT6516 directly connect to 16 port RMII PHY or 12 port MII PHY device which compliant with
IEEE standard (Please see IEEE 802.3u Fast Ethernet standard) . Each Fast Ethernet port has following
characteristics:
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Capable of supporting both 10MBps and 100MBps data rates in half and full duplex modes.
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Provide a simple management interface (SMI) for port status
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Perform all functions of the IEEE 802.3 protocol such as frame formatting, frame stripping, collision
handling, deferred, etc.
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Adjustable preamble ,SFD and inter frame gap (IFG).
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IEEE 802.3X flow control supported
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IEEE 802.1D spanning tree protocol support, and all port state of listen and block configurable
3.1.4.1 RMII interface
The VT6516 communicates with the external 10/100M Ethernet transceiver through the reduced MII
(RMII) interface. The signals of RMII interface are described in Table-3-1
Table 3-1 RMII interface signals
Name
CRSDV
Type
I
Description
Carrier sense and Data
valid
Receive data bit 0 to 1 ,
data rate with 50MHz
Transmit Enable
Transmit Data bit 0 to
1
RXD[0-1]
I
TXEN
TXD[0-1]
O
O
Figure 3-1 RMII timing diagram
(omitted)