AD9958SLASHPCB datasheet(22/40 Pages) AD

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AD9958

Rev. 0 | Page 22 of 40

2-Level Modulation Using Profile Pins for RU/RD

When the RU/RD bit = 01, Profile Pins P2 and P3 are available

for RU/RD. Note that only a modulation level of two is available

in this mode. See Table 13 for available pin assignments.

Table 13.

Profile Pin

Config. Bits

FR1 <14:12>

Description

CH0

CH1

CH0

CH1

2-level

modulation

RU/RD

With RU/RD, CH0,

CH1

8-Level Modulation Using a Profile Pin for RU/RD

When the RU/RD bit = 10, Profile Pin P3 is available for

RU/RD. Note that only a modulation level of eight is available.

See Table 14 for available pin assignments.

Table 14.

Profile Pin Config. Bits

FR1 <14:12>

Description

CH0 CH0 CH0 CH0

RU/RD

8-level modulation

with RU/RD,

CH0

CH1 CH1 CH1 CH1

RU/RD

8-level modulation

with RU/RD,

CH1

MODULATION USING SDIO PINS FOR RU/RD

For RU/RD bits = 11, SDIO Pins 1, 2, and 3 are available for

RU/RD. In this mode, modulation levels of 2/4/16 are available.

Note that the serial I/O port can only be used in 1-bit serial

mode.

2-Level Modulation Using SDIO Pins for RU/RD

Table 15.

Profile Pin Config. Bits

FR1 <14:12>

N/A

CH0

CH1

For this configuration, each profile pin is dedicated to a specific

channel. In this case, the SDIO pins can be used for the RU/RD

function, as described in Table 16.

Table 16.

SDIO Pins

Description

Triggers the ramp-up function for CH0

Triggers the ramp-down function for CH0

Triggers the ramp-up function for CH1

Triggers the ramp-down function for CH1

4-Level Modulation Using SDIO Pins for RU/RD

For RU/RD = 11 (SDIO Pins 1 and 2 are available for RU/RD),

the modulation level is set to four. See Table 17 for pin

assignments, including SDIO pin assignments.

Table 17.

Profile Pin Config.

Bits FR1 <14:12>

SDIO 1 SDIO 2 SDIO 3

CH0 CH0

CH1 CH1 CH0

CH1

N/A

RU/RD RU/RD

For the configuration shown in Table 17, the profile register is

chosen based on the two bit value presented to <P1:P2> or

<P3:P4>.

For example, if PPC = 101, <P0:P1> = 11, and <P2:P3> = 01,

then the contents of Profile Register 3 of Channel 0 are

presented to Channel 0’s output and the contents of Profile

SDIO Pins 1 and 2 provide the RU/RD function.

16-Level Modulation Using SDIO Pins for RU/RD

RU/RD = 11 (SDIO Pin 1 available for RU/RD) and the level is

set to 16. See the pin assignment shown in the Table 18.

Table 18.

Profile Pin

Configuration

FR1<14:12>

SDIO

CH0

RU/RD

CH1

RU/RD

For the configuration shown in Table 18, the profile register is

chosen based on the 4-bit value presented to <P0:P3>. For

example, if PPC = X11 and <P0-P3> = 1101, then the contents

of Profile Register 13 of Channel 1 is presented to Channel 1.

The SDIO_1 pin provides the RU/RD function.

LINEAR SWEEP (SHAPED) MODULATION MODE

Linear sweep enables the user to sweep frequency, phase, or

amplitude from a starting point (S0) to an endpoint (E0). The

purpose of linear sweep modes is to provide better bandwidth

containment compared to direct modulation by replacing

greater instantaneous changes with more gradual, user-defined

changes between S0 and E0.

In linear sweep mode, S0 is loaded into Profile Register 0

(Profile 0 is represented by one of the three Registers 0x04,

0x05, or 0x06 depending on the type of sweep) and E0 is always

loaded into Profile Register 1 (Register 0x0A). If E0 is

configured for frequency sweep, the resolution is 32 bits, phase

sweep is 14 bits, and amplitude sweep is 10 bits. When sweeping

phase or amplitude, the word value must be MSB-aligned in

Profile 1 register. The unused bits are don’t care bits.

The profile pins are used to trigger and control the direction of

the linear sweep for frequency, phase, and amplitude. Both

channels can be programmed separately for a linear sweep. In

linear sweep mode, Profile Pin 2 is dedicated to Channel 0.

Profile Pin 3 is dedicated to Channel 1, and so on.

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