Programming Description

GENERAL PROGRAMMING INFORMATION

The serial interface has a 24-bit shift register to store the incoming data bits temporarily. The incoming data is loaded into the shift

register from MSB to LSB. The data is shifted at the rising edge of the clock signal. When the latch enable signal transitions from

LOW to HIGH, the data stored in the shift register is transferred to the proper register depending on the address bit settings. The

selection of the particular register is determined by the address bits equal to the binary representation of the number of the control

register.

At initial start-up, the MICROWIRE loading requires 4 default words (registers R3, loaded first, to R0, loaded last). After the device

has been initially programmed, the RF VCO frequency can be changed using a single register (R0). If an IF frequency other than

the default value for the device is desired the SPI_DEF bit should be set to 0, the desired values for IF_A, IF_B, and IF_R entered

and words R6 to R0 should be sent.

The control register content map describes how the bits within each control register are allocated to the specific control functions.

COMPLETE REGISTER MAP

MSB

SHIFT REGISTER BIT LOCATION

LSB

23

22

21

20 19

18 17 16 15 14 13 12

11

10 9 8 7 6 5

4

3

2

1 0

R0

(Default)

SPI_

DEF

RF_

SEL

RF_

LD

0

RF_B

[3:0]

RF_A

[2:0]

RF_FN

[10:0]

00

R1

(Default)

IF_

FREQ

[1:0]

OSC_

FREQ

10

000000

SPUR_

RDT

[1:0]

0

0 1 0 1 OB_

CRL

[1:0]

RF_

EN

IF_

EN

01

R2

(Default)

IF_

CUR[1:0]

0

0

1

0

011101

1

0

1 0 1 0 0

0

1

0

10

R3

(Default)

BW_

DUR

[1:0]

BW_

CRL

[1:0]

BW_

EN

1011110

1

0

0 0 1 1 0

VCO_

CUR

[1:0]

01 1

R4

0

0

0

1

0

0

0

IF_A

[3:0]

IF_B

[8:0]

01

1 1

R5

0

0

1

1

0

0

0010

IF_R

[8:0]

01

1

1 1

R6

1

0

0

0

0

0

000000

0

0

0 0 0 0 011

1

1 1

NOTE: Bold numbers represent the address bits.

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