AD9954

Rev. 0 | Page 17 of 36

Table 8. Register Map–When Linear Sweep Enable Bit Is True (CFR1<21> = 1).

Note that the RAM enable Bit CFR1<31> only activates the RAM itself not the RAM segment control words.

Register

Name

(Serial

Address)

Bit Range

(MSB)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

(LSB)

Bit 0

Default

Value

OR

Profile

<7:0>

Digital

Power-

Down

Comp

Power-

Down

DAC

Power-

Down

Clock

Input

Power

Dwn

External

Power-

Down

Mode

CRYSTAL

OUT Pin

Active

SYNC_CLK

Out

Disable

Not

Used

0x00

<15:8>

Load SRR

@ I/O UD

AutoClr

Freq.

Accum

AutoClr

Phase

Accum

Enable

SINE

Output

Clear

Freq

Accum.

Clear

Phase

Accum.

SDIO

Input

Only

LSB First

0x00

<23:16>

Automatic

Sync

Enable

Software

Manual

Sync

Linear

Sweep

Enable

Not Used

Not

Used

Not Used

Not Used

Not

Used

0x00

Control

Function

Register No.

1 (CFR1)

(0x00)

<31:24>

RAM

Enable

RAM

Dest. Is

Phase

Word

Internal Profile Control <2:0>

Load ARR

@ I/O UD

Output

Shaped

Keying

Enable

Auto

Output

Shaped

Keying

0x00

<7:0>

REFCLK Multiplier

0x00 or 0x1 or 0x02 or 0x03: Bypass Multiplier

0x04 to 0x14: 4× to 20× Multiplication

VCO

Range

Charge Pump Current

<1:0>

0x00

<15:8>

Not Used

High

Speed

Sync

Enable

Hardware

Manual

Sync

Enable

CRYSTAL

OUT Pin

Active

Not

Used

0x00

Control

Function

Register No.

2 (CFR2)

(0x01)

<23:16>

Not Used

0x00

<7:0>

(0x07)

Amplitude Scale Factor Register <7:0>

Amplitude

Scale Factor

(ASF) (0x02)

<15:8>

Auto Ramp Rate

Speed Control <1:0>

Amplitude Scale Factor Register <13:8>

Amplitude

Ramp Rate

(ARR) (0x03)

<7:0>

Amplitude Ramp Rate Register <7:0>

<7:0>

Frequency Tuning Word No. 0 <7:0>

0x00

<15:8>

Frequency Tuning Word No. 0 <15:8>

0x00

<23:16>

Frequency Tuning Word No. 0 <23:16>

0x00

Frequency

Tuning

Word

(FTW0)

(0x04)

<31:24>

Frequency Tuning Word No. 0 <31:24>

0x00

<7:0>

Phase Offset Word No. 0 <7:0>

0x00

Phase Offset

Word

(POW0)

(0x05)

<15:8>

Open<1:0>

Phase Offset Word No. 0 <13:8>

0x00

<7:0>

Frequency Tuning Word No. 1 <7:0>

<15:8>

Frequency Tuning Word No. 1 <15:8>

<23:16>

Frequency Tuning Word No. 1 <23:16>

Frequency

Tuning

Word

(FTW1)

(0x06)

<31:24>

Frequency Tuning Word No. 1 <31:24>

<7:0>

Falling Delta Frequency Tuning Word <7:0>

PS0 = 0

<15:8>

Falling Delta Frequency Tuning Word <15:8>

PS0 = 0

<23:16>

Falling Delta Frequency Tuning Word <23:16>

PS0 = 0

<31:24>

Falling Delta Frequency Tuning Word <31:24>

PS0 = 0

Negative

Linear

Sweep

Control

Word

(NLSCW)

(0x07)

<39:32>

Falling Sweep Ramp Rate Word <7:0>

PS0 = 0