83C795 Datasheet, PDF (12/136 Pages) List of Unclassifed Manufacturers – Ethernet System Controller

FUNCTIONAL DESCRIPTION
83C795
3.0 FUNCTIONAL DESCRIPTION
T he principle s ections of the device are the:
• Host interface which mediates host access to
internal registers and buffer memory.
• LAN Controller which performs 802.3 MAC
layer protocol and does supporting DMA
transfers to and from local buffer memory.
• Serial line interface which supplies drivers and
receivers for AUI and TP interfaces and port
control logic for the 10BASE-T interface. In
addition, it provides Manchester encoding and
decoding.
3.1 DESCRIPTION OF DATA PATH
F i gure 3-1 i ll us tr ates the data path for a
83C795-bas ed board. All internal byte s wapping is
handled by the memory cache. T he data bus
drivers are des igned to drive the IS A bus directly.
3.2 CONVENTIONS
Anumber of conventions areus edin this databook.
1. A bit may be described as "low" or "logical 0"
when its value is set to 0. A bit is described
as "high" or "logical 1" when its value is set
to 1.
2. The location of a bit is frequently described
in this manner:
<register>.<bit>
For example, since the bit MENB is located
in the CR Register, it might be described in
this book as CR.MENB. Or, alternatively,
since MENB is the sixth bit in the CR Regis-
ter, it might also be described in this manner:
CR.6
3