STW81102ATR datasheet(28/43 Pages) STMICROELECTRONICS

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I2C bus interface

STW81102

28/43

and P is the selected Prescaler Modulus

5.3.6

CALIBRATION

This register controls VCO calibrator.

INITCAL:

resets the auto-calibrator State Machine (writing to "1" and back to "0")

SERCAL:

at "1" starts the VCO auto-calibration (should be reset to "0" at the end of

calibration)

SELEXTCAL: test purpose only; must be set to '0'

CAL[4:0]:

test purpose only; must be set to '0'

5.3.7

READ-ONLY register

This register is automatically addressed in the 'current byte address read mode'.

DEV_ID[1:0]:

device identifier bits; returns '00'

LOCK_DET:

"1" when PLL is locked

INTCAL[4:0]:

internal value of the VCO control word

5.3.8

Default configuration

At Power On Reset the following configuration is automatically loaded:

–

FUNCTIONAL MODE = 1 (VCOA with divided by 2 output)

–

A COUNTER = 8

–

B COUNTER = 562

–

R DIVIDER = 192

–

PLL_A[1:0] = [10]

–

CP_SEL[2:0] = [111]

–

PSC_MOD_SEL set to "0" (Modulus = 16)

This is corresponding to an output frequency of 1800MHz and a PFD frequency of 400KHz

using a 76.8MHz reference clock (calibration algorithm of the VCO is automatically started).

for Direct Output

where DR equals

0.5

for Output Divided by 2

0.25

for Output Divided by 4

MSB

LSB

INIT

CAL

SER

CAL

SEL

EXT

CAL

CAL4

CAL3

CAL2

CAL1

CAL0

MSB

LSB

DEV_ID1

DEV_ID0

LOCK_

DET

INT

CAL4

INT

CAL3

INT

CAL2

INT

CAL1

INT

CAL0

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