
44
Am79C965A
Note that the RXCRS pin is multiplexed with the A27
pin.
SRDCLK
Serial Receive Data Clock
SRDCLK is an input. Rising edges of the SRDCLK sig-
nal are used to sample the data on the RXDAT input
whenever the RXCRS input is HIGH.
Input/Output
Note that the SRDCLK pin is multiplexed with the A26
pin.
RXDAT
Receive Data
RXDAT is an input. Rising edges of the SRDCLK signal
are used to sample the data on the RXDAT input when-
ever the RXCRS input is HIGH.
Input/Output
Note that the RXDAT pin is multiplexed with the A25
pin.
IEEE 1149.1 Test Access Port Interface
TCK
Test Clock
The clock input for the boundary scan test mode opera-
tion. TCK can operate up to 10 MHz. If left unconnected
this pin has a default value of HIGH.
TDI
Test Data Input
The test data input path to the PCnet-32 controller. If
left unconnected, this pin has a default value of HIGH.
TDO
Test Data Output
The test data output path from the PCnet-32 controller.
TDO is floated when the JTAG port is inactive.
TMS
Test Mode Select
A serial input bit stream is used to define the specific
boundary scan test to be executed. If left unconnected,
this pin has a default value of HIGH.
Power Supply Pins
AVDD
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
Input
Input
Output
Input
Power
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)
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 to the
PCnet Family Technical Manual
for details.
DVDD
Digital Power (3 Pins)
There are 3 digital power supply pins. (DVDD1,
DVDD2, and DVDD3) used by the internal circuitry.
DVDDCLK
Digital Power Clock (1 Pin)
This pin is used to supply power to the clock buffering
circuitry.
DVDDO
I/O Buffer Digital Power (5 Pins)
There are 5 digital power supply pins (DVDD01
–
DVDD05) used by Input/Output buffer drivers.
DVSS
Digital Ground (4 Pins)
There are 4 digital ground pins (DVSS1
–
DVSS4) used
by the internal digital circuitry.
DVSSCLK
Digital Ground Clock (1 Pin)
This pin is used to supply a ground to the clock
buffering circuitry.
DVSSN
I/O Buffer Digital Ground (15 Pins)
These 15 ground pins (DVSSN1
–
DVSSN15) are used
by the Input/Output buffer drivers.
DVSSPAD
Digital Ground Pad (1 Pin)
This pin is used by the Input/Output logic circuits.
Power
Power
Power
Power
Ground
Ground
Ground
Ground