AM79C940VCW datasheet(28/122 Pages) AMD

tên linh kiện	AM79C940VCW

Giải thích chi tiết về linh kiện	Media Access Controller for Ethernet (MACE)

PDF	122 Pages

Scroll/Zoom	100%

nhà sản xuất	AMD [Advanced Micro Devices]

Trang chủ	http://www.amd.com

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28 / 122 page

AMD

Am79C940

sort of operation are bridges and routers. Lack of

perfect filtering in these applications forces the CPU to

be more involved in filtering and thus either slows the

forwarding rates achieved or forces the use of a more

powerful CPU.

DTV

The DTV pin is part of the host interface to the MACE

device. It is used to indicate that a read or write cycle to

the MACE device was successful. If DTV is not asserted

at the end of a cycle, the data transfer was not success-

ful. Basically, this will happen on a write to a full transmit

FIFO or a read from an empty receive FIFO. In general,

there are ways to ensure that a transfer is always valid

and so this pin is not required in many designs. For in-

stance, the TDTREQ and RDTREQ pins can be used to

monitor the state of the FIFOs to ensure that data trans-

fer only occurs at the correct times.

RXPOL

RXPOL is typically used to drive an LED indicating the

polarity of receive frames. This function is not neces-

sary for correct operation of the Ethernet and serves

strictly as a status indication to a user. The status of the

receive polarity is still available through the PHYCC

AM79C940VCW bảng dữ liệu(PDF) 28 Page - Advanced Micro Devices