am79c970 Advanced Micro Devices, am79c970 Datasheet - Page 19

• Manufacturer Part Number: am79c970
• Description: Pcnettm-pci Single-chip Ethernet Controller For Pci Local Bus
• Manufacturer: Advanced Micro Devices

Attachment Unit Interface
CI
Collision In
Input
A differential input pair signaling the PCnet-PCI control-
ler that a collision has been detected on the network me-
dia, indicated by the CI inputs being driven with a
10 MHz pattern of sufficient amplitude and pulse width
to meet ISO 8802-3 (IEEE/ANSI 802.3) standards. Op-
erates at pseudo ECL levels.
DI
Data In
Input
A differential input pair to the PCnet-PCI controller car-
rying Manchester encoded data from the network. Oper-
ates at pseudo ECL levels.
DO
Data Out
Output
A differential output pair from the PCnet-PCI controller
for transmitting Manchester encoded data to the net-
work. Operates at pseudo ECL levels.
Twisted-Pair Interface
RXD
10BASE-T Receive Data
Input
10BASE-T port differential receivers.
TXD
10BASE-T Transmit Data
Output
10BASE-T port differential drivers.
TXP
10BASE-T Pre-Distortion Control
Output
These outputs provide transmit pre-distortion control in
conjunction with the 10BASE-T port differential drivers.
Test Interface
NOUT
NAND Tree Out
Output
The results of the NAND tree testing can be observed on
the NOUT pin. NOUT will be constantly high, when RST
is deasserted.
1-886
AMD
P R E L I M I N A R Y
Am79C970
Power Supply Pins
Analog Power Supply Pins
AVDD
Analog Power (4 Pins)
Power
There are four analog +5 V supply pins. Special atten-
tion should be paid to the printed circuit board layout to
avoid excessive noise on these lines. Refer to Appendix
B and the PCnet Family Technical Manual (PID
#18216A) for details.
AVSS
Analog Ground (2 Pins)
Power
There are two analog ground pins. Special attention
should be paid to the printed circuit board layout to avoid
excessive noise on these lines. Refer to Appendix B and
the PCnet Family Technical Manual (PID #18216A) for
details.
Digital Power Supply Pins
VDD
Digital Power (6 Pins)
Power
There are 6 power supply pins that are used by the inter-
nal digital circuitry. All VDD pins must be connected to a
+5 V supply.
VDDB
I/O Buffer Power (4 Pins)
Power
There are 4 power supply pins that are used by the PCI
bus Input/Output buffer drivers. All VDDB pins must be
connected to a +5 V supply.
VSS
Digital Ground (12 Pins)
Ground
There are 12 ground pins that are used by the internal
digital circuitry.
VSSB
I/O Buffer Ground (8 Pins)
Ground
There are 8 ground pins that are used by the PCI bus In-
put/Output buffer drivers.