Analog Devices UG-002, AD9551 Using Software To Calculate The Device Settings, Feedback Window

UG-002

Feedback Window

Clicking Click for Details in the Feedback Divider box of the main window accesses the Feedback window, which allows you to change the feedback divider settings (see Figure 15).

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Figure 15. Feedback Window

P0, P1, and P2 (Output Dividers) Boxes

Selecting the SPI check box in any of the divider settings boxes (that is, the P0, P1, or P2 box) in the main window enables a drop-down selection of predetermined divider settings (see Figure 16).

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Figure 16. P0, P1, and P2 Boxes (in Main Window)

Output Loop Config: Box

The Output Loop Config: box can be used to change the output frequency of the AD9551. This control changes the logic levels of the output frequency selection pins of the AD9551.

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Figure 17. Output Loop Config: Box (in Main Window)

Evaluation Board User Guide

OutSel Pin: Box

The OutSel Pin: drop-down box (see Figure 18) in the main window controls the logic level on the OUTSEL pin of the AD9551. However, this value can be overwritten by using the SPI control register.

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Figure 18. OutSel Pin Box (in Main Window)

USING SOFTWARE TO CALCULATE THE DEVICE SETTINGS

The following procedure explains how the evaluation board software can be used to automatically calculate and set the settings to program the AD9551.

In this example, the input frequency is 122.88 MHz on REF A, and the output frequency is 122.88 MHz.

1.Ensure that Jumper JMP3 is positioned for PC control.

2.Verify that all five jumpers are in place on Connector P2.

3.Set the positions of the S1, S2, and S3 dip switches to high.

4.Click Calculate Device Settings in the main window of the evaluation board software.

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Figure 19. Calculate Device Settings Button (in Main Window)

5.The Enable Control? window, shown in Figure 20, appears.

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Figure 20. AD9551 Serial Port Programming Warning

6.Click Yes to enable serial port register programming.

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