crashmeplease
New Member
I am looking for ways to protect/disable a logic circuit both during power up, and possibly if the micro controller enters an invalid state, even if unlikely.
The best thing I could think of for simplicity was using transistors as logic gates, thus when one input is high and the other low (driven by the micro) then enables my logic circuit (low output). See attached.
While the idea is basic, it serves that the inputs must be in a predetermined stage to enable the logic circuit. I was thinking of trying to add in a little RC network stage to delay from power on.
Are there any other simple ways to do this? If I just control the logic enable directly with a single micro output, I can see there could be times during power on/reset/programming when the logic circuit could possibly be enabled. Requiring both a high and low pin to enable the logic circuit should add an extra layer of safety?
Although if there was a problem with the micro once it was initialised, potentially the predetermined on state could remain on, however unlikely?
TIA
The best thing I could think of for simplicity was using transistors as logic gates, thus when one input is high and the other low (driven by the micro) then enables my logic circuit (low output). See attached.
While the idea is basic, it serves that the inputs must be in a predetermined stage to enable the logic circuit. I was thinking of trying to add in a little RC network stage to delay from power on.
Are there any other simple ways to do this? If I just control the logic enable directly with a single micro output, I can see there could be times during power on/reset/programming when the logic circuit could possibly be enabled. Requiring both a high and low pin to enable the logic circuit should add an extra layer of safety?
Although if there was a problem with the micro once it was initialised, potentially the predetermined on state could remain on, however unlikely?
TIA