2.5 R2 REGISTER

The R2 Register is used to setup the FastLock circuitry for the IF synthesizer.

Reg

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9876543210

DATA[20:0]

C2

C1

C0

R2

0000000

IF_TOC[13:0]

0

1

0

2.5.1 IF_TOC[13:0] — FastLock Timeout Counter, IF Synthesizer

The IF_TOC[13:0] word controls the operation of the IF FastLock circuitry as well as the function of the FLoutIF output pin. When

IF_TOC is set to a value between 0 and 3, the IF timeout counter is disabled and the FLoutIF pin operates as a general purpose

I/O pin. When IF_TOC is set to a value between 4 and 16383, the IF FastLock mode is enabled and FLoutIF is utilized as the IF

FastLock output pin. The value programmed into IF_TOC represents the number of phase comparison cycles that the IF

synthesizer will spend in the FastLock state.

IF_TOC[13:0]

FastLock Mode

FastLock Period

[CP Events]

FLoutIF Pin Functionality

0

Disabled

N/A

High Impedance

1

Disabled

N/A

Logic LOW State

2

Manual

N/A

Logic LOW State. Force IF Charge Pump to 800 µA

3

Disabled

3

Logic HIGH State

4

Enabled

4

FastLock

…

Enabled

…

FastLock

16,383

Enabled

16383

FastLock

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