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=== Temperature sensor on SOC ===
The internal temperature sensor of iMX8M Mini /Nano SOC has some limitations regarding the operative range (from 10 to 105°C) and the precision (±5 accuracy).
If the operative temperature is a crucial parameter on the system where MITO 8M Mini /Nano is integrated, we suggest adding one or more temperature sensors on the carrier board in order to overcome these limitations.
In the following '''Software thermal protection''' chapter, the implementation of reading and trip points management are referred at the internal SOC temperature sensor.
See [[MITO 8M Mini SOM/MITO 8M Mini Hardware/Electrical Thermal and Mechanical Features/Mechanical specifications|Mito 8M Mini/Nano Board Layout]] section for more details.
==== SOM Thermography ====
The following image is taken in stress tests conditions (see [[MITO 8M Mini SOM/MITO 8M Mini Hardware/Electrical Thermal and Mechanical Features/Operational characteristics#Use cases results|this section]]) without any heatsinkin order to highlight the hot spots on this board. The hottests points here are:
* the CPU
* the PMIC
* the Ethernet PHY (iperf test was enable during this test)
Depending on your application it is may needed to dissipate heat not only from CPU but also other areas (the thermal analysis is important in conjunction with the temperature range of each component which may be 125°C or 150°C). Depending on the application running, this platform can be suitable for fanless approach.
[[File:1200px-Mito8MMini nand all.png|none|thumb|374x374px]]
===Software thermal protection ===
In [[DESK-MX8MX8M-L| DESK-MX8M-L]], two software thermal protection mechanisms are implemented. Both are based on the processor's temperature sensor. It is worth remembering that maximum junction temperature (also denoted as Tj in the rest of the document) is:
*95°C for Consumer parts
====U-Boot====
At U-Boot level, automatic boot procedure is halted until Tj is smaller greater than (following temperatures might seem excessively low but they take into account the intrinsic poor precision of the temperature sensor to provide a reasonable safe margin):
*'''TBD''' 85°C for Consumer parts
*95°C for Industrial parts
====Linux kernel====
At Linux level, a more sophisticated protection mechanism is implemented. Please refer to the following sections for more details.
*for Consumer parts
** passive threshold: '''TBD'''85°C** critical threshold: '''TBD'''90°C{| style="color:#000000; border:solid 2px #73B2C7; background-color:#ededed;font-size:95%; vertical-align:middle;"|[[File:TBD.png|30px]]|'''Section not completed yet'''|}
*for Industrial parts
** passive threshold: 85°C95°C** critical threshold: 95°C100°C
**
thermal thermal_zone0: critical temperature reached(95 C),shutting down
</pre>
To resume the CPU from the shutdown, the CPU_ONOFF signal must be externally managed. Please contact [mailto:sales@dave.eu sales@dave.eu] for any additional information.
By default, temperature thresholds are set up as follows: