Kinetis MicrocontrollersのトピックAdd a delay between A/D sample and conversion https://community.nxp.com/t5/Kinetis-Microcontrollers/Add-a-delay-between-A-D-sample-and-conversion/m-p/662141#M40641 <HTML><HEAD></HEAD><BODY><P>Kinetis K64: I have a short window of opportunity (like 300 ns) to sample a signal before process noise corrupts it. Unfortunately, the process noise also corrupts the conversion process, so I need to sample &amp; hold the signal at one moment, then convert it during the next quiet moment. The reference manual says the conversion always immediately follows the sample, but I need to put a delay between these two actions. I don't think I can turn off the A/D peripheral after the sample while still preserving the sample, can I? How about reducing the A/D clock to zero Hertz right after the sample but before the conversion? If I then wait for a quiet moment to re-enable the A/D clock, would it still perform the conversion correctly? Are there any other techniques I could use to delay the conversion process after taking a sample? Or is there an app note which can help the conversion process become more immune to noise spikes on 3.3V/GND? I'm not using the 1.2V external voltage reference, would that help? Thanks!</P></BODY></HTML> Wed, 22 Feb 2017 18:18:54 GMT brianzenowich 2017-02-22T18:18:54Z Add a delay between A/D sample and conversion https://community.nxp.com/t5/Kinetis-Microcontrollers/Add-a-delay-between-A-D-sample-and-conversion/m-p/662141#M40641 <HTML><HEAD></HEAD><BODY><P>Kinetis K64: I have a short window of opportunity (like 300 ns) to sample a signal before process noise corrupts it. Unfortunately, the process noise also corrupts the conversion process, so I need to sample &amp; hold the signal at one moment, then convert it during the next quiet moment. The reference manual says the conversion always immediately follows the sample, but I need to put a delay between these two actions. I don't think I can turn off the A/D peripheral after the sample while still preserving the sample, can I? How about reducing the A/D clock to zero Hertz right after the sample but before the conversion? If I then wait for a quiet moment to re-enable the A/D clock, would it still perform the conversion correctly? Are there any other techniques I could use to delay the conversion process after taking a sample? Or is there an app note which can help the conversion process become more immune to noise spikes on 3.3V/GND? I'm not using the 1.2V external voltage reference, would that help? Thanks!</P></BODY></HTML> Wed, 22 Feb 2017 18:18:54 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/Add-a-delay-between-A-D-sample-and-conversion/m-p/662141#M40641 brianzenowich 2017-02-22T18:18:54Z Re: Add a delay between A/D sample and conversion https://community.nxp.com/t5/Kinetis-Microcontrollers/Add-a-delay-between-A-D-sample-and-conversion/m-p/662142#M40642 <HTML><HEAD></HEAD><BODY><P>Hi</P><P></P><P>K64 ADC module conversion clock frequency in range of 1MHz to 18MHz, there could not be halted during ADC sample and conversion.</P><P><span class="lia-inline-image-display-wrapper" image-alt="pastedImage_1.png"><img src="https://community.nxp.com/t5/image/serverpage/image-id/14124i32E8D48AA0F3DBB5/image-size/large?v=v2&amp;px=999" role="button" title="pastedImage_1.png" alt="pastedImage_1.png" /></span></P><P>Customer could consider to replace K64 product with LPC546xx product, which provides up to 5Msamples/s 12-bit ADC module.</P><P>More detailed info, please check <A href="http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/lpc-mcus/lpc54000-series-cortex-m4-mcus/power-efficient-microcontrollers-mcus-with-advanced-peripherals-based-on-arm-cortex-m4-core:LPC546XX">here</A>.</P><P><BR />Wish it helps.</P><P></P><P>Have a great day,<BR />Ma Hui<BR />-----------------------------------------------------------------------------------------------------------------------<BR />Note: If this post answers your question, please click the Correct Answer button. Thank you!<BR />-----------------------------------------------------------------------------------------------------------------------</P></BODY></HTML> Mon, 27 Feb 2017 09:15:54 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/Add-a-delay-between-A-D-sample-and-conversion/m-p/662142#M40642 Hui_Ma 2017-02-27T09:15:54Z