DP83907VF National Semiconductor, DP83907VF Datasheet - Page 46

• 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
Error Recovery
If the packet is rejected as shown the DMA is restored by
the DP83907 by reprogramming the DMA starting address
pointed to by the Current Page Register
Storage Format for Received Packets
The following diagrams describe the format for how re-
ceived packets are placed into memory by the local DMA
channel These modes are selected in the Data Configura-
tion Register
BOS
Series 32xxx or 808xx processors
BOS
680 x 0 type processors (Note the Receive Count ordering remains the
same for BOS
BOS
general 8-bit processors
6 4 PACKET TRANSMISSION
The Local DMA is also used during transmission of a pack-
et Three registers control the DMA transfer during trans-
mission a Transmit Page Start Address Register (TPSR)
and the Transmit Byte Count Registers (TBCR0 1) When
the DP83907 receives a command to transmit the packet
pointed to by these registers buffer memory data will be
moved into the FIFO as required during transmission The
DP83907 will generate and append the preamble synch
and CRC fields
AD15
AD15
e
e
e
Receive Byte Count 1
0 WTS
Receive Byte Count 0
1 WTS
0 WTS
Next Packet Pointer
Next Packet Pointer
e
Byte 2
Byte 1
e
e
e
0 or 1 )
0 in Data Configuration Register This format is used with
1 in Data Configuration Register This format is used with
1 in Data Configuration Register This format is used with
Receive Byte Count 0
Receive Byte Count 1
Next Packet Pointer
AD8
AD8
Receive Status
Byte 0
Byte 1
AD7
AD7
Receive Byte Count 0
Receive Byte Count 1
Receive Status
Receive Status
Byte 1
Byte 2
(Continued)
AD0
AD0
46
Transmit Packet Assembly
The DP83907 requires a contiguous assembled packet with
the format shown The transmit byte count includes the
Destination Address Source Address Length Field and
Data It does not include preamble and CRC When trans-
mitting data smaller than 46 bytes the packet must be pad-
ded to a minimum size of 64 bytes The programmer is re-
sponsible for adding and stripping pad bytes
The packets are placed in the buffer RAM by the system In
I O Mode the system programs the NIC Core’s Remote
DMA to mode the data from the data port to the RAM hand-
shaking with system transfers loading the I O data port In
Shared Memory Mode the packets are written directly to the
RAM by system using standard memory transfer instruc-
tions (MOV)
For I O mode the data transfer must be 16 bits (1 word)
when in 16 bit mode and 8 bits when the DP83907 is set in
8 bit mode The data width is selected by setting the WTS
bit in the Data Configuration Register and setting the DWID
pin for the proper mode
In Shared Memory mode data transfer can be accomplished
by using either 8- or 16-bit data transfer instructions be-
cause this mode responds to 8 16 bit data signaling on the
ISA bus In this mode Shared Memory Control Register 2 bit
6 sets the bus interface data width and the NIC Core’s data
width is set by the WTS bit in the Data Configuration Regis-
ter
Transmission
Prior to transmission the TPSR (Transmit Page Start Regis-
ter) and TBCR0 TBCR1 (Transmit Byte Count Registers)
must be initialized To initiate transmission of the packet the
TXP bit in the Command Register is set The Transmit
Status Register (TSR) is cleared and the DP83907 begins to
prefetch transmit data from memory (unless the DP83907 is
currently receiving) If the interframe gap has timed out the
DP83907 will begin transmission
TBCR0 1
Transmit
Count
Byte
General Transmit Packet Format
Pad (if data
Destination Address
Source Address
Type Length
Data
k
46 Bytes)
t
6 Bytes
6 Bytes
2 Bytes
46 Bytes