AMD Am7990 Manual de referência - Página 3

Procurar online ou descarregar pdf Manual de referência para Controlador AMD Am7990. AMD Am7990 12 páginas. Ethernet/cheapernet family

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OVERVIEW
This reference guide provides design consideration notes
relating to the Am7990 IEEE 802.3 (EthernetiCheapernet)
family of products. Consult you local AMD sales office,
AMD representative or AMD authorized distributor for any
questions concerning device price and/or availability.
DEVICE NOMENCLATURE
The following denotes the current device nomenclature:
Am7990DCnO (LANCE)
-
Replaced Am7990DC/60
Rev. D product
Am7992BDC (SIA)
-
Replaced Am7992ADC and
wide package Am7991 ADC
Am7996DC (Transceiver) -
Replaced Am7995DC
I. OVERVIEW OF Am7990
ETHERNET/CHEAPERNET FAMILY
The implementation of 10M bits/sec baseband networking
referred to as Ethernet or Cheapernet has been simplified
by the availability of three devices-the Am7990 Local
Area Network Controller for Ethernet (LANCE), the
Am7992B Serial Interface Adapter (SIA) and the Am7996
Transceiver.
Devices in the Am7990 Family support both Ethernet
and Cheapernet configurations. Cheapernet is Ethernet on
cheaper cables, has fewer nodes, and shorter distance but
provides the same 10M bits/sec performance. This high-
performance chip family is compatible with IEEE 802.3, the
industry standard for EthernetiCheapernel.
The Am7990 Family was produced through joint devel-
opment work with Digital Equipment Corporation (Am7990
LANCE and Am7992B SIA) and 3COM (Am7996). Op-
timum performance of this family has been assured
through rigorous testing in various network configurations.
The Am7990 LANCE features buffer management with
descriptor rings to substantially reduced CPU overhead. Its
24-bit-wide linear address provides direct memory address
(DMA) into the entire memory space of all major 16-bit
microprocessors.
The Am7992B SIA is a Manchester encoder-decoder
that provides the connection between the LANCE and the
Ethernet transceiver. The SIA features include transient
noise suppression and guaranteed signal threshold limits
in both data and collision paths.
The Am7996 Transceiver provides all the transmit,
receive and collision detection functions with respect to the
coax transmiSSion media. The Am7996 features include an
optional Signal Quality Error (SQE) test function, and noise
rejection filters on both transmit and receive data.
Together, these three devices provide a complete inte-
grated solution for IEEE 802.3, Ethernet, and Cheapernet
networking applications.
Ethernet/IEEE 802.3 Type A
Ethernet
COAX
DTE • Data Terminal Equipment
AUI - Attachment Unit Interface
MAU - Media Attachment Unit
• High AC/DC impedance tap
• AUI drop cable «50 meters)
• Very low loss COAX
I
1-;::===:::;" ---
~
~
~
~
~
~
Iii
~.
~
Iii
I
Iii
•• -Iii
~
• Nonintrusive Node attachment
Figure 1A.
3
08496A-1
OVERVIEW
This reference guide provides design consideration notes
relating to the Am7990 IEEE 802.3 (EthernetiCheapernet)
family of products. Consult you local AMD sales office,
AMD representative or AMD authorized distributor for any
questions concerning device price and/or availability.
DEVICE NOMENCLATURE
The following denotes the current device nomenclature:
Am7990DCnO (LANCE)
-
Replaced Am7990DC/60
Rev. D product
Am7992BDC (SIA)
-
Replaced Am7992ADC and
wide package Am7991 ADC
Am7996DC (Transceiver) -
Replaced Am7995DC
I. OVERVIEW OF Am7990
ETHERNET/CHEAPERNET FAMILY
The implementation of 10M bits/sec baseband networking
referred to as Ethernet or Cheapernet has been simplified
by the availability of three devices-the Am7990 Local
Area Network Controller for Ethernet (LANCE), the
Am7992B Serial Interface Adapter (SIA) and the Am7996
Transceiver.
Devices in the Am7990 Family support both Ethernet
and Cheapernet configurations. Cheapernet is Ethernet on
cheaper cables, has fewer nodes, and shorter distance but
provides the same 10M bits/sec performance. This high-
performance chip family is compatible with IEEE 802.3, the
industry standard for EthernetiCheapernel.
The Am7990 Family was produced through joint devel-
opment work with Digital Equipment Corporation (Am7990
LANCE and Am7992B SIA) and 3COM (Am7996). Op-
timum performance of this family has been assured
through rigorous testing in various network configurations.
The Am7990 LANCE features buffer management with
descriptor rings to substantially reduced CPU overhead. Its
24-bit-wide linear address provides direct memory address
(DMA) into the entire memory space of all major 16-bit
microprocessors.
The Am7992B SIA is a Manchester encoder-decoder
that provides the connection between the LANCE and the
Ethernet transceiver. The SIA features include transient
noise suppression and guaranteed signal threshold limits
in both data and collision paths.
The Am7996 Transceiver provides all the transmit,
receive and collision detection functions with respect to the
coax transmiSSion media. The Am7996 features include an
optional Signal Quality Error (SQE) test function, and noise
rejection filters on both transmit and receive data.
Together, these three devices provide a complete inte-
grated solution for IEEE 802.3, Ethernet, and Cheapernet
networking applications.
Ethernet/IEEE 802.3 Type A
Ethernet
COAX
DTE • Data Terminal Equipment
AUI - Attachment Unit Interface
MAU - Media Attachment Unit
• High AC/DC impedance tap
• AUI drop cable «50 meters)
• Very low loss COAX
I
1-;::===:::;" ---
~
~
~
~
~
~
Iii
~.
~
Iii
I
Iii
•• -Iii
~
• Nonintrusive Node attachment
Figure 1A.
3
08496A-1