AM79C90 Advanced Micro Devices, AM79C90 Datasheet - Page 18

• Manufacturer Part Number: AM79C90
• Description: CMOS Local Area Network Controller for Ethernet (C-LANCE)
• Manufacturer: Advanced Micro Devices

Differences Between Ethernet Versions 1
and 2
a. Version 2 specifies that the collision detect of the
b. Version 2 specifies some network management
c. Version 2 specifies that when transmission is ter-
Differences Between IEEE 802.3 and
Ethernet
a. IEEE 802.3 specifies a 2-byte length field rather
b. IEEE 802.3 allows the use of a PAD field in the
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transceiver must be activated during the inter-
packet gap time.
functions, such as reporting the occurrence of colli-
sions, retries and deferrals.
minated, the differential transmit lines are driven to
0 volt differentially (half step).
than a type field. The length field (802.3) describes
the actual amount of data in the frame.
data section of a frame, while Ethernet specifies
the minimum packet size at 64 bytes. The use of a
PAD allows the user to send and receive packets
which have less than 46 bytes of data.
AMD
P R E L I M I N A R Y
Am79C90
A list of significant differences between Ethernet and
IEEE 802.3 at the physical layer include the following:
End of Transmission
State
Common Mode Voltage
Common Mode Current Less than 1 mA
Receive , Collision
Input Threshold
Fault Protection
IEEE 802.3
Half Step
160 mV
16 V
5.5 V
Half Step (Rev 2)
Full Step (Rev 1)
1.6 mA 40%
Ethernet
0 – +5 V
175 mV
0 V
or