AMD
P R E L I M I N A R Y
28
Am79C970A
operates in the same signaling environment as the PCI
bus interface.
TDI
Test Data In
TDI is the test data input path to the PCnet-PCI II con-
troller. The pin has an internal pull-up resistor. The TDI
input operates in the same signaling environment as the
PCI bus interface.
Input
TDO
Test Data Out
TDO is the test data output path from the PCnet-PCI II
controller. The pin is tri-stated when the JTAG port is in-
active. The TDO output operates in the same signaling
environment as the PCI bus interface.
Output
TMS
Test Mode Select
A serial input bit stream on the TMS pin is used to define
the specific boundary scan test to be executed. The pin
has an internal pull-up resistor. The TMS input operates
in the same signaling environment as the PCI
bus interface.
Input
Test Interface
NOUT
NAND Tree Out
When
RST
is asserted, the results of the NAND tree
testing can be observed on the NOUT pin.
Output
Note that the NOUT pin is multiplexed with the
DXCVR pin.
Power Supply Pins
AV
DD
Analog Power (4 Pins)
There are four analog +5 V supply pins. Special atten-
tion should be paid to the printed circuit board layout to
Power
avoid excessive noise on these lines. Refer to
Appendix B and the PCnet Family Board Design and
Layout Recommendations application note (PID
#19595A) for details.
AV
SS
Analog Ground (2 Pins)
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 Board Design and Layout
Recommendations application note (PID #19595A)
for details.
Power
V
DD
Digital Power (6 Pins)
There are six power supply pins that are used by the in-
ternal digital circuitry. All V
DD
pins must be connected to
a +5 V supply.
Power
V
DDB
I/O Buffer Power (4 Pins)
There are four power supply pins that are used by the
PCI bus input/output buffer drivers. In a system with 5 V
signaling environment, all V
DDB
pins must be connected
to a +5 V supply. In a system with 3.3 V signaling
nvironment, all V
DDB
pins must be connected to a
+3.3 V supply.
Power
V
SS
Digital Ground (12 Pins)
There are 12 ground pins that are used by the internal
digital circuitry.
Ground
V
SSB
I/O Buffer Ground (8 Pins)
There are 8 ground pins that are used by the PCI bus in-
put/output buffer drivers.
Ground