DP83905AVQB National Semiconductor, DP83905AVQB Datasheet - Page 37

• Manufacturer Part Number: DP83905AVQB
• Description: IC CONTROLR AT/LAN TP IN 160PQFP
• Manufacturer: National Semiconductor
• Series: AT/LANTIC™r

Specifications of DP83905AVQB

• Controller Type: AT, LAN Twisted-Pair Interface Controller
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 100mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 160-BFQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Interface: -
• Other names: *DP83905AVQB

D1 and
Bits
5 0 Register Descriptions
TRANSMIT CONFIGURATION REGISTER (TCR)
The transmit configuration establishes the actions of the transmitter section of the AT LANTIC Controller during transmission of
a packet on the network LB1 and LB0 which select Ioopback mode power up as 0
D0
D2
D3
D4
D5
D6
D7
Symbols
CRC
LB0 and
LB1
ATD
OFST
reserved
reserved
reserved
INHIBIT CRC
In loopback mode CRC can be enabled or disabled to test the CRC logic
ENCODED LOOPBACK CONTROL These encoded configuration bits set the type of loopback that is to be
performed Note that loopback in mode 2 places the ENDEC Module in loopback mode and that D3 of the
DCR must be set to zero for loopback operation
Mode 0
Mode 1
Mode 2
Mode 3
AUTO TRANSMIT DISABLE This bit allows another station to disable the AT LANTIC Controller’s
transmitter by transmission of a particular multicast packet The transmitter can be re-enabled by resetting
this bit or by reception of a second particular multicast packet
0 Normal Operation
1 Reception of multicast address hashing to bit 62 disables transmitter reception of multicast address
COLLISION OFFSET ENABLE This bit modifies the backoff algorithm to allow prioritization of nodes
0 Backoff Logic implements normal algorithm
1 Forces Backoff algorithm modification to 0 to 2
reserved
reserved
reserved
0 CRC appended by transmitter
1 CRC inhibited by transmitter
hashing to bit 63 enables transmitter
follows standard backoff (For the first three collisions the station has higher average backoff delay
making a low priority mode )
7
6
LB1
0
0
1
1
5
(Continued)
LB0
0
1
0
1
OFST
4
ODH (WRITE)
Normal Operation (LPBK
Internal NIC Module Loopback (LPBK
Internal ENDEC Module Loopback (LPBK
External Loopback (LPBK
37
ATD
3
Description
min(3
a
LB1
n 10)
2
e
e
slot times for first three collisions then
0)
0)
LB0
1
e
0)
e
CRC
1)
0