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Watchdog Power Requirement for EN50271 standard (STM8L152)

Question asked by Chris Reynard on Jun 13, 2018
Latest reply on Jun 19, 2018 by Chris Reynard



I am looking at using a STM8L152 MCU in a product that detects and measures a combustible gas.


There are standards that govern how these products must operate, one of which is EN 50271:2010.


STM8L152 has a built-in watchdog feature but for this to satisfy the 'monitoring equipment' requirements of the standard it must operate separately from the main data processing function. This includes the voltage supply. It is okay for the monitoring equipment and data processing function to be connected to the same power supply but they should be connected 'separately'. This is not easy to demonstrate when the watchdog and main data processing function are packaged together.


I have looked through various published datasheets/technical docs/ref manual but have not come across detail which would provide assurance that this requirement is being met.


The main data processing function derives power from a power regulator (which in turn is fed from Vdd1,Vss1). If there is a block diagram or schematic that demonstrates power to the watchdog feature is not derived from this same regulator function then I believe the standards will be met.


Does anyone have any experience with this kind of thing, or be able to point me in the right direction? 


Kind Regards