My Hardware has STM32L162VD as main processor and other modules on it like GPRS module SIM900. I noticed that when the hardware is under test after few hours the floating point numbers in RAM registers change only in '.' character to some other characters like 't' or space ' ' or '*' or '0'. I mean the numbers don't change but only the appearance of point changes. I can see the values in Graphical 128x64 LCD and also in the server computer that receives the data using GPRS TCP connection. The numbers change like following every few hours: 1.5 -> 1t5 12.54 -> 12t54 or 1.5 -> 105 12.54 ->12054 or 1.5 ->1 5 12.54 ->12 54
if I write the changed number into the EEPROM and reset the MCU then read it from EEPROM the number goes back to normal appearance. I don't know what is happening to MCU!