DP83256VF National Semiconductor, DP83256VF Datasheet - Page 50

• 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

D0-D7
5 0 Registers
5 6 INJECTION THRESHOLD REGISTER (IJTR)
The Injection Threshold Register in conjunction with the Injection Control bits (IC
(CTSR) set the frequency at which the contents of the Injection Symbol Register A (ISRA) and Injection Symbol Register B
(ISRB) are inserted into the data stream It contains the start value for the Injection Counter
The Injection Threshold Register value is loaded into the Injection Counter when the counter reaches zero or during every
Control Bus Interface write-cycle of this register
The Injection Counter is an 8-bit down-counter which decrements every 80 ns It’s current value is read for CIJCR
The counter is active only during One Shot or Periodic Injection Modes (i e Injection Control
Current Transmit State Register (CTSR) are set to either 01 or 10) The Transmitter Block will replace a data symbol pair with
ISRA and ISRB when the counter reaches 0 and the Injection Mode is either One Shot or Periodic
If the Injection Threshold Register is set to 0 during the One Shot mode the JK will be replaced with ISRA and ISRB If the
Injection Threshold Register is set to 0 during the Periodic mode all data symbols are replaced with ISRA and ISRB
The counter is initialized to 0 during the reset process (i e E RST
For further information see the INJECTION CONTROL LOGIC section
ACCESS RULES
Bit
IJT7
D7
ADDRESS
IJT0 –IJT7
Symbol
05h
IJT6
D6
INJECTION THRESHOLD BIT
IJT0 is the Least Significant Bit (LSB)
(Continued)
Always
READ
IJT5
D5
IJT4
D4
WRITE
Always
k
0-7
l
IJT3
D3
Start value for the Injection Counter
50
e
Description
GND)
IJT2
D2
k
1 0
IJT1
l
D1
) in the Current Transmit State Register
k
1 0
IJT0
D0
l
bits (IC
k
1 0
l
) of the