DP83907VF National Semiconductor, DP83907VF Datasheet - Page 45

• Manufacturer Part Number: DP83907VF
• Description: IC CONTROLLR AT/LANII TP 160PQFP
• Manufacturer: National Semiconductor

Specifications of DP83907VF

• Controller Type: Network Interface Controller (NIC)
• Interface: Twisted Pair
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 150mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 160-MQFP, 160-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *DP83907VF

6 0 Operation of DP83907
Enabling the DP83907 on an Active Network
After the DP83907 has been initialized the procedure for
disabling and then re-enabling the DP83907 on the network
is similar to handling Receive Buffer Ring overflow as de-
scribed previously
10) Put DP83907 in START mode (Command Register
11) Initialize the Transmit Configuration for the intended
End of Packet Operations
At the end of the packet the DP83907 determines whether
the received packet is to be accepted or rejected It either
branches to a routine to store the Buffer Header or to anoth-
er routine that recovers the buffers used to store the packet
1) Program Command Register for page 0 (Command
2) lnitialize Data Configuration Register (DCR)
3) Clear Remote Byte Count Registers (RBCR0 RBCR1)
4) lnitialize Receive Configuration Register (RCR)
5) Place the DP83907 in LOOPBACK mode 1 or 2 (Trans-
6) Initialize Receive Buffer Ring
7) CIear Interrupt Status Register (ISR) by writing OFFH to
8) lnitialize Interrupt Mask Register (IMR)
9) Program Command Register for page 1 (Command
22H) The local receive DMA is still not active since the
DP83907 is in LOOPBACK
value The DP83907 is now ready for transmission and
reception
Register
if using Remote DMA
mit Configuration Register
(BNDRY)
(PSTOP)
it
Register
i) Initialize Physical Address Registers (PAR0– PAR5)
ii) Initialize Multicast Address Registers (MAR0 –
iii) Initialize CURRENT pointer
MAR7)
FIGURE 33 Received Packet Aborted
e
e
Page Start (PSTART)
21H)
61H)
if it Hits Boundary
e
02H or 04H)
Boundary Pointer
and Page Stop
(Continued)
TL F 12082– 28
e
45
Successful Reception
If the packet is successfully received the DMA is restored
to the first buffer used to store the packet (pointed to by the
Current Page Register) The DMA then stores the Receive
Status a Pointer to where the next packet will be stored
(Buffer 4) and the number of received bytes Note that the
remaining bytes in the last buffer are discarded and recep-
tion of the next packet begins on the next empty 256-byte
buffer boundary The Current Page Register is then initial-
ized to the next available buffer in the Buffer Ring (The
location of the next buffer had been previously calculated
and temporarily stored in an internal scratchpad register )
Buffer Recovery for Rejected Packets
If the packet is a runt packet or contains CRC or Frame
Alignment errors it is rejected The buffer management log-
ic resets the DMA back to the first buffer page used to store
the packet (pointed to by CURR) recovering all buffers that
had been used to store the rejected packet This operation
will not be performed if the DP83907 is programmed to ac-
cept either runt packets or packets with CRC or Frame
Alignment errors The received CRC is always stored in
buffer memory after the last byte of received data for the
packet
FIGURE 34 Termination of Received
FIGURE 35 Termination of Receive
Packet-Packet Accepted
Packet-Packet Reject
TL F 12082 – 29
TL F 12082 – 30