# Direct sampling on XTRX?

**URL:** <https://discourse.myriadrf.org/t/direct-sampling-on-xtrx/8609>\
**Category:** System Development\
**Created:** [2 January 2025 19:09 UTC](https://discourse.myriadrf.org/t/direct-sampling-on-xtrx/8609 "2025-01-02T19:09:41Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sdruser256](https://avatars.discourse-cdn.com/v4/letter/s/f14d63/32.png) [@sdruser256](https://discourse.myriadrf.org/u/sdruser256)\
**Post date:** [2 January 2025 19:09 UTC](https://discourse.myriadrf.org/t/direct-sampling-on-xtrx/8609/1 "2025-01-02T19:09:41Z")

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I’d like to use the 15 pin FPC connectors on the XTRX to access the ADCs and DACs directly, for 4 channels of direct RX and TX.

I see that there are some flags to configure in the LMS7002M in order to route signal from dedicated pins to the ADC, and to route signal from the DAC to dedicated pins. Is there a guide or other information online somewhere that would be useful for this configuration?

Thanks

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**Author:** ![andrewback](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@andrewback](https://discourse.myriadrf.org/u/andrewback)\
**Post date:** [3 January 2025 12:31 UTC](https://discourse.myriadrf.org/t/direct-sampling-on-xtrx/8609/2 "2025-01-03T12:31:05Z")

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You can find all the docs here:

> **[GitHub - myriadrf/LMS7002M-docs: Documentation for the Lime Microsystems second...](https://github.com/myriadrf/LMS7002M-docs)**
>
> Documentation for the Lime Microsystems second generation transceiver IC

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<div class="post-metadata">

**Author:** ![sdruser256](https://avatars.discourse-cdn.com/v4/letter/s/f14d63/32.png) [@sdruser256](https://discourse.myriadrf.org/u/sdruser256)\
**Post date:** [24 February 2025 20:41 UTC](https://discourse.myriadrf.org/t/direct-sampling-on-xtrx/8609/3 "2025-02-24T20:41:21Z")

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I have reviewed the documentation, and was able to successfully use the ADCs directly, by modifying “OSW\_PGA\_RBB\_[N]” bit 15.

I have not been able to successfully access the DACs directly. How can this be done? The documentation indicates “TSTIN\_TBB\_[N]” can be modified, but when I modify it to different values, I never get any signal out of the DAC pads.

How can I accomplish this? Thanks in advance