DP83256VF datasheet(50/144 Pages) NSC

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50 Registers (Continued)

56 INJECTION THRESHOLD REGISTER (IJTR)

The Injection Threshold Register in conjunction with the Injection Control bits (ICk10l) in the Current Transmit State Register

(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 (ie Injection Controlk10l bits (ICk10l)ofthe

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 (ie ERSTeGND)

For further information see the INJECTION CONTROL LOGIC section

ACCESS RULES

ADDRESS

READ

WRITE

05h

Always

IJT7

IJT6

IJT5

IJT4

IJT3

IJT2

IJT1

IJT0

Bit

Symbol

Description

D0-D7

IJT0 – IJT7

INJECTION THRESHOLD BITk0-7l

Start value for the Injection Counter

IJT0 is the Least Significant Bit (LSB)

DP83256VF датащи(PDF) 50 Page - National Semiconductor (TI)