https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1754344#M215459 <P>Hi all,<BR />I can observe a 10°C dispersion on temperature measured from the chip sensor on different iMX boards.<BR />(on imx8mm yocto image, using cat /sys/class/thermal/thermal_zone0/temp)<BR />Here, under same conditions on 2 different chips (chipmin and chipmax):<BR />Tchipmin=58°<BR />Tchipmax=69°<BR />I can also read my chips' TE1 and TE2 temperature values stored in fuses (from the 25°C and 85°C NXP measurement during manufacturing process) :<BR />TE1chipmin=50° TE2chipmin=112°<BR />TE1chipmax=61° TE2chipmax=120°<BR />They follow the same trend : some chips are cooler, some are hotter.<BR /><STRONG>This feels to me like a sensor offset issue which (I hope) can be corrected by calibration.</STRONG><BR /><BR />I tried to follow the software calibration as explained in the RM 5.4.5 Temperature Sensor Error Correction Method. But I'm really lost and confused because of poor explanation and a lack of context :</P><P>- what are the conditions of TE1 (room temp) and TE2 (hot temp) measures ? What is CPU load, or power consumption, what is the kernel doing, which image is running ? and are the 2 measurements consistent (under same conditions) ?<BR /><BR />- Can we simply apply a slope compensation on the sensor value in a different operating condition, as suggested ?<BR />According to me the temperature error / difference between 2 chips is mainly due to 2 factors : different power consumption / heating (intrinsic, because the chip is physically different) and temp sensor precision. How can we isolate them ? Is it safe to consider it is only due to sensor calibration ?<BR /><BR />- Let's try on my 2 chips, chipmin and chipmax samples :<BR />TCALIBchipmin=(58-50)×(85-25)/(112-50)+25=32° ?<BR />TCALIBchipmax=(69-61)×(85-25)/(120-61)+25=33° ?<BR />What is TCALIB meaning ? OK now the values are closer but It's definitely not the chip temp !</P><P>- And by the way, what is this reference curve they are talking about ?</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="antho_0-1699459357097.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/249044iE1F61A274844D087/image-size/medium?v=v2&amp;px=400" role="button" title="antho_0-1699459357097.png" alt="antho_0-1699459357097.png" /></span></P><P>We need more context</P><P><BR /><BR /></P> Wed, 08 Nov 2023 16:48:16 GMT antho 2023-11-08T16:48:16Z https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1754344#M215459 <P>Hi all,<BR />I can observe a 10°C dispersion on temperature measured from the chip sensor on different iMX boards.<BR />(on imx8mm yocto image, using cat /sys/class/thermal/thermal_zone0/temp)<BR />Here, under same conditions on 2 different chips (chipmin and chipmax):<BR />Tchipmin=58°<BR />Tchipmax=69°<BR />I can also read my chips' TE1 and TE2 temperature values stored in fuses (from the 25°C and 85°C NXP measurement during manufacturing process) :<BR />TE1chipmin=50° TE2chipmin=112°<BR />TE1chipmax=61° TE2chipmax=120°<BR />They follow the same trend : some chips are cooler, some are hotter.<BR /><STRONG>This feels to me like a sensor offset issue which (I hope) can be corrected by calibration.</STRONG><BR /><BR />I tried to follow the software calibration as explained in the RM 5.4.5 Temperature Sensor Error Correction Method. But I'm really lost and confused because of poor explanation and a lack of context :</P><P>- what are the conditions of TE1 (room temp) and TE2 (hot temp) measures ? What is CPU load, or power consumption, what is the kernel doing, which image is running ? and are the 2 measurements consistent (under same conditions) ?<BR /><BR />- Can we simply apply a slope compensation on the sensor value in a different operating condition, as suggested ?<BR />According to me the temperature error / difference between 2 chips is mainly due to 2 factors : different power consumption / heating (intrinsic, because the chip is physically different) and temp sensor precision. How can we isolate them ? Is it safe to consider it is only due to sensor calibration ?<BR /><BR />- Let's try on my 2 chips, chipmin and chipmax samples :<BR />TCALIBchipmin=(58-50)×(85-25)/(112-50)+25=32° ?<BR />TCALIBchipmax=(69-61)×(85-25)/(120-61)+25=33° ?<BR />What is TCALIB meaning ? OK now the values are closer but It's definitely not the chip temp !</P><P>- And by the way, what is this reference curve they are talking about ?</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="antho_0-1699459357097.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/249044iE1F61A274844D087/image-size/medium?v=v2&amp;px=400" role="button" title="antho_0-1699459357097.png" alt="antho_0-1699459357097.png" /></span></P><P>We need more context</P><P><BR /><BR /></P> Wed, 08 Nov 2023 16:48:16 GMT https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1754344#M215459 antho 2023-11-08T16:48:16Z https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1755661#M215570 <P>Hello,</P> <P>&nbsp;</P> <P>In which i.MX8 is present this situation because the MX8MM the presented scenario is ok, the MX8QX need SCFW porting please check:</P> <P><A href="https://community.nxp.com/t5/i-MX-Processors/how-to-get-temperature-and-set-CPU-frequency-in-sc-fireware/m-p/981493" target="_blank">https://community.nxp.com/t5/i-MX-Processors/how-to-get-temperature-and-set-CPU-frequency-in-sc-fireware/m-p/981493</A></P> <P>&nbsp;</P> <P>Regards</P> Fri, 10 Nov 2023 14:39:35 GMT https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1755661#M215570 Bio_TICFSL 2023-11-10T14:39:35Z https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1755693#M215572 <P>Hi,<BR />It's in the title <LI-EMOJI id="lia_winking-face" title=":winking_face:"></LI-EMOJI> I'm working on the IMX8MM.<BR />How can you explain a 32°C chip temperature ? It seems surprisingly low !<BR /><BR />(kernel is based on the linux-imx_5.4.70_2.3.0 NXP branch)</P> Fri, 10 Nov 2023 15:46:22 GMT https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1755693#M215572 antho 2023-11-10T15:46:22Z https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1763257#M216333 <P>Hi all,</P><P>Have you found any solutions?<BR />I am experiencing a similar issue on two different devices with the same IMX8MM model running the same software.<BR />Thanks in advance,</P><P>Lucien</P> Fri, 24 Nov 2023 09:37:37 GMT https://community.nxp.com/t5/i-MX-Processors/imx8mm-temperature-sensor-calibration/m-p/1763257#M216333 lucienlachance 2023-11-24T09:37:37Z