https://community.nxp.com/t5/S32K/Inaccurate-sampling-in-S32K/m-p/2020751#M44674 <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="企业微信截图_17356334435198.png" style="width: 999px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/317737iDEB19FD782C77003/image-size/large?v=v2&amp;px=999" role="button" title="企业微信截图_17356334435198.png" alt="企业微信截图_17356334435198.png" /></span></P><P><SPAN>The multimeter measures FUEL_SENSOR_1_CAPACITAL1 1.3 mV, but the actual value printed by the MCU serial port is 7mV.Is it the sampling network that's incorrect?</SPAN></P> Tue, 31 Dec 2024 08:39:33 GMT Hailong_Zeng 2024-12-31T08:39:33Z https://community.nxp.com/t5/S32K/Inaccurate-sampling-in-S32K/m-p/2020751#M44674 <P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="企业微信截图_17356334435198.png" style="width: 999px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/317737iDEB19FD782C77003/image-size/large?v=v2&amp;px=999" role="button" title="企业微信截图_17356334435198.png" alt="企业微信截图_17356334435198.png" /></span></P><P><SPAN>The multimeter measures FUEL_SENSOR_1_CAPACITAL1 1.3 mV, but the actual value printed by the MCU serial port is 7mV.Is it the sampling network that's incorrect?</SPAN></P> Tue, 31 Dec 2024 08:39:33 GMT https://community.nxp.com/t5/S32K/Inaccurate-sampling-in-S32K/m-p/2020751#M44674 Hailong_Zeng 2024-12-31T08:39:33Z https://community.nxp.com/t5/S32K/Inaccurate-sampling-in-S32K/m-p/2022622#M44824 <P>Hello&nbsp;<a href="https://community.nxp.com/t5/user/viewprofilepage/user-id/242056">@Hailong_Zeng</a>&nbsp;,</P> <P>I apologize for late response caused by Xmas vacations.</P> <P>At first look, your C4116 and C4117 have low capacitance.&nbsp;<SPAN>Please refer to&nbsp;</SPAN><A href="https://www.nxp.com/docs/en/application-note/AN4373.pdf" target="_blank" rel="nofollow noopener noreferrer">AN4373, Cookbook for SAR ADC Measurements - Application note (nxp.com)</A><SPAN>&nbsp;. E.g. for S32K3, necessary information (CS, CP1, CP2, RSW, RAD, ...) to calculate values of external components can be found in chapter 10.1 of S32K3 data sheet.</SPAN></P> <P><SPAN>While you are sensing mV, I also recommend to have separate ground path for your signal from source to MCU. The ground path shall be separated in a way that no other current flows through this path.</SPAN></P> <P>Best regards,</P> <P>Pavel</P> Mon, 06 Jan 2025 14:52:16 GMT https://community.nxp.com/t5/S32K/Inaccurate-sampling-in-S32K/m-p/2022622#M44824 PavelL 2025-01-06T14:52:16Z