For procurement reasons, we had to switch from MKW21 to MKW22 MCUs on our production line. They are supposed to be pin-to-pin compatible.
After having resolved a big problem with the configuration of the MKW22 clock (see my previous post External crystal clock on MKW22 MCU not working), I now have a new problem with this processor.
We just started to produce boards with the MKW22 and we observed a problem during production: around 1 board over 3 produced does not work, the problem seems to be a the 802.15.4 level. The other produced boards work without problem.
I also observed that all the non working boards are overheating: When I plug a board and the software is running on it, it start heating and reach 50°C after +/- 20 seconds. On the working boards, the temperature of the MCU is stable at 25°C in the same conditions.
I suppose that the problems observed on the 802.15.4 are coming from this overheating problem (the clock must be slightly different because of the temperatyre). Please note that all the boards we produced previously with the MKW21 had no problem.
Where does this behaviour could come from ? What can we do to prevent it ? Is it due to hardware or software ?
It could be a peripheral badly initialised with no default reset value, or a random one, but which one ?
This is really urgent and the production is now stuck because of that.