[SOLVED] logic question protect switch from accidentally pressing

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neazoi

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Hello I have an application that uses the logic attached.
The write switch, writes the contents of some registers to the memory, when the left switch is switched in the program position and also in the run position.

Is there any way to prevent the write switch from accidentally being pressed, when the left switch is in run mode?
 

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Hi,

Define Accidental and Intentional from the switches point of view !:lol:

Suppose all you can do is write a subroutine so the Write Switch has to be held down for say over 1 second to be assumed Intentional or something similar if you are meaning the Run mode is a running program ?

If your circuit / run mode is some form of programming set up , then you could use something like a res/cap on the switch so it has to be held On for some time to charge the cap up to the full positive level. Also need a res/diode to quickly discharge the cap when the switch is Off.
 
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    neazoi

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run mode is when the cpu runs the stored program, that has been previously programmed in the program mode, using the /prg write.

when it is in the run mode, no-one should press the /prg write switch.

I was thinking of a way to automatically set the /prg write to 1, using gates, when /run mode is at 0, so that the effect of the write switch is irrelevand
 


Problem solved. The use of another OR gate alows the /PRG WRITE to be set on zero, when we are only on program mode and when the write button has been pressed.
I think I am right?
 

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