[AD9102/06] PAT_TIMEBASE settings

Hello,

i'm using AD9102 with SRAM Data output. Generally it works, my used Clock Rate is 25MHz so quite low for the device.

I've got some trouble with the PAT_TIMEBASE settings:

For PAT_TIMEBASE = 0x0FF1 -> Hold Sample for 15 clocks, 15 DAC clocks per PATTERN_PERIOD LSB
the output works fine but i'm wasting a lot of clock cycles.

I would like to generate one sample with every DAC clock, therefore put PAT_TIMEBASE = 0x0111. If i do so and start the DAC output i can see a short pulse with my first SRAM Data Value and then the DAC returns to idle immediately.

I've tried several combinations of Hold times and DAC clocks per PATTERN_PERIOD LSB. For DAC clocks per PATTERN_PERIOD i can go down to one and still see my output. But when i set a hold time < 6 Samples the same result as for the 0x111 setting appears.

The "fastest" Setting i can use is PAT_TIMEBASE = 0x0611 -> Hold Sample for 6 Clocks, 1 DAC clock per PATTERN_PERIOD LSB. Due to the hold time != clocks per PATTERN_PERIOD LSB only the first 1/6 of my Pattern gets sampled.

Where am i going wrong? Why can i use a prestored waveform with output on every DAC clock but not on the SRAM output?

I'm thankful for any advice,

greetings
Lauri

  • 0
    •  Analog Employees 
    on Oct 12, 2020 1:08 AM 1 month ago

    Hi Lauri,

    Please confirm if I understood your question - you want to generate a continuous waveform using SRAM data?
    If yes, please set value of PATTERN_PERIOD register equal to 4096 base 10 or 0x1000 - the number of SRAM samples.
    Your PAT_TIMEBASE value of 0x0111 is correct.

    Best regards,
    Shine