DP83256VF National Semiconductor, DP83256VF Datasheet - Page 13

• Manufacturer Part Number: DP83256VF
• Description: IC FDDI LAYER CTRLR 160PQFP
• Manufacturer: National Semiconductor
• Series: PLAYER+™r

Specifications of DP83256VF

• Controller Type: physical layer controller
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 160-BFQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Supply: -
• Interface: -
• Other names: *DP83256VF

3 0 Functional Description
DATA REGISTERS
Data from the Configuration Switch is stored in the Data
Registers The 10-bit byte-wide data consists of a parity bit
a control bit and two 4-bit data symbols as shown below
The parity is odd parity The control bit determines whether
the Data bits represent Data or Control information When
the control bit is 0 the Data field is interpreted as data and
when it is 1 the field is interpreted as control information
according to the National Semiconductor control codes
PARITY CHECKER
The Parity Checker verifies that the parity bit in the Data
Register represents odd parity (i e odd number of 1s)
The parity is enabled and disabled through bit 6 (PRDPE) of
the Current Transmit State Register (CTSR)
If a parity error occurs the Parity Checker will set bit 0 (DPE)
in the Interrupt Condition Register (ICR) and report the error
to the Repeat Filter
4B 5B ENCODER
The 4B 5B Encoder converts the two 4-bit data symbols
from the Configuration Switch into their respective 5-bit
codes
See Table 3-2 for the Symbol Encoding list
Parity Bit Control Bit
b9
FIGURE 3-4 Byte-Wide Data
b8
b7
Data Bits
(Continued)
b0
13
Note The upper group of symbols are sent with the Control Data pin set to
Data while the bottom grouping of symbols are sent with the Control Data
pin set to Control
REPEAT FILTER
The Repeat Filter is used to prevent the propagation of
code violations to the downstream station
Upon receiving violations in data frames the Repeat Filter
replaces them with two Halt symbol pairs followed by Idle
symbols Thus the code violations are isolated and recov-
ered at each link and will not be propagated throughout the
entire ring
JK (Starting
T (Ending
R (Reset)
Symbol
Delimiter)
Delimiter)
A
B
C
D
E
N
0
1
2
3
4
5
6
7
8
9
F
TABLE 3-2 4B 5B Symbol Encoding
4B Code
0100 or
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
0000
1101
0101
0110
11000 and
5B Code
11110 or
11110
01001
10100
10101
01010
01011
01110
01111
10010
10011
10110
10111
11010
11011
11100
11101
11111
10001
01101
00111