SLWU087E november 2013 – june 2023
The following example shows what must be modified in the DAC3XJ8X GUI for a setup using 4 lanes, 1x interpolation, and a DAC sample rate of 368.64M.
After opening the DAC GUI, enter the parameters as shown in Figure 10-2.
The GUI calculates the lane rate and displays it in the box called SerDes Linerate. For this example, the lane rate is 7372.8Mbps. Using the lane rate conditions in Section 10.1, REFCLK = 368.64 MHz and Core clock = 184.32 MHz.
Click on the Program LMK04828 and DAC3XJ8X button. After the programming has completed, click on the LMK04828 Controls tab. Next click on the Clock Outputs tab.
For the DAC3XJ8X GUI, the REFCLK is provided by CLKout 0 and the Core clock is provided by CLKout 12. Notice that the default setting for CLKout 12 is Group Powerdown, as shown in Figure 10-3.
Since the DAC Clock is 368.64 MHz, to provide a REFCLK of 368.64 MHz, change the DCLK Divider for CLKout 0 to “8”.
To generate a Core clock of 184.32 MHz, set the DCLK Divider for CLKout 12 to “16”. Also, remove the checkmark from the Group Powerdown box to enable this output. The Clock Outputs menu is now as seen in Figure 10-4.
Open HSDC Pro GUI, select the DAC tab, then select DAC3XJ84_LMF_442 in the device button. After the firmware is loaded, enter 368.64M in the Data Rate (SPS) window, select 2’s Complement in the DAC Option window and generate a 10-MHz test tone using the IQ Multitone Generator located in the lower left of the GUI. Click on the Create Tones button. The display looks as shown in Figure 10-5.
Click the Send button. A new window opens showing the lane rate of the interface and the required frequency of REFCLK, as shown in Figure 10-6.
Go back to the DAC GUI Quick Start tab and click on Reset DAC JESD Core. Click on Trigger LMK04828 SYSREF. There should now be a 10-MHz tone present at all four DAC EVM outputs.