DP83934CVUL20 National Semiconductor, DP83934CVUL20 Datasheet - Page 7

• Manufacturer Part Number: DP83934CVUL20
• Manufacturer: National Semiconductor

Specifications of DP83934CVUL20

• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (max): 5.25V
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 160
• Lead Free Status / RoHS Status: Not Compliant

NETWORK INTERFACE PINS (Continued)
TXD
EXUSR3
TXE
TXCo
TXCi
STERM
LBK
EXUSR2
PCOMP
PREJ
Symbol
2 0 Pin Description
Driver
Type
TRI
TRI
TRI
TRI
TP
TP
TP
Direction
O Z
O Z
O Z
O Z
O
O
O
I
I
I
(Continued)
This pin will be TRI-STATE until the DCR has been written to (See Section 6 3 2 EXBUS for
more information )
TRANSMIT DATA (TXD) The serial NRZ data from the MAC unit which is to be decoded by an
external ENDEC Data is valid on the rising edge of TXC Although this signal is used internally by
the SONIC-T it is also provided as an output to the user
EXTENDED USER OUTPUT (EXUSR3) When EXBUS has been set (see Section 6 3 2) this pin
becomes a programmable output It will remain TRI-STATE until the SONIC-T becomes a bus
master at which time it will be driven according to the value programmed in the DCR2 (see
Section 6 3 7)
TRANSMIT ENABLE This pin is driven high when the SONIC-T begins transmission and remains
active until the last byte is transmitted Although this signal is used internally by the SONIC-T it is
also provided as an output to the user
This pin will be TRI-STATE until the DCR has been written to (See Section 6 3 2
EXBUS for more information )
TRANSMIT CLOCK OUTPUT (TXCo) from the internal ENDEC (EXT
clock output is derived from the 20 MHz oscillator input When EXT
internally connected between the ENDEC and MAC units Although this signal is used internally
by the SONIC-T it is also provided as an output to the user
TRANSMIT CLOCK INPUT (TXCi) from an external ENDEC (EXT
external ENDEC is used for shifting data out of the MAC unit serializer This clock is nominally
10 MHz
SYNCHRONOUS TERMINATION (STERM) When the SONIC-T is a bus master it samples this
pin before terminating its memory cycle This pin is sampled synchronously and may only be used
in asynchronous bus mode when BMODE
This pin will be TRI-STATE until the DCR has been written to (See Section 6 3 2 EXBUS for
more information )
LOOPBACK (LBK) When ENDEC Loopback mode is enabled LBK is asserted high Although
this signal is used internally by the SONIC-T it is also provided as an output to the user
EXTENDED USER OUTPUT (EXUSR2) When EXBUS has been set (see Section 6 3 2) this pin
becomes a programmable output It will remain TRI-STATE until the SONIC-T becomes a bus
master at which time it will be driven according to the value programmed in the DCR2 (see
Section 6 3 7)
PACKET COMPRESSION This pin is used with the Management Bus of the DP83950 Repeater
Interface Controller (RIC) The SONIC-T can be programmed to assert PCOMP whenever there is
a CAM match or when there is not a match The RIC uses this signal to compress (shorten) a
received packet for management purposes and to reduce memory usage (See the DP83950
datasheet for more details on the RIC Management Bus ) The operation of this pin is controlled
by bits 1 and 2 in the DCR2 register PCOMP will remain TRI-STATE until these bits are written to
This signal is asserted right after the 4th bit of the 7th byte of the incoming packet and is
deasserted one transmit clock (TXC) after CSR is driven low
PACKET REJECT This signal is used to reject received packets When asserted low for at least
two receive clock cycles (RXC) the SONIC-T will reject the incoming packet This pin can be
asserted up to the 2nd to the last bit of reception to reject a packet
TABLE 2-1 Pin Description (Continued)
7
Description
e
1 (See Section 7 2 5 for more details )
e
e
1) This input clock from an
e
0 the TXCo signal is
0) This 10 MHz transmit