hi guys,
I am working on a project based on AT89C55. Here i am connecting sensors, switches to controller through optocoupler[MCT2E] & buffer[74LS244].Design attached with this thread.Plz check & suggest me on follwing problem.
Whenever i press the PB it gives 1.8 Vdc on buffer's i/p pin instead of which it should give 0 Vdc , So that same should reflect at buffer's o/p pin.But here buffers o/p pin always give 4 Vdc. If i check this by removing buffer IC then it gives correct result. Wat could be the problem?
I have added RC for removing key debounceing effect.
Plz give ur valuable suggestion.........i stuck up at this point & cant go ahead.
Thnks.
I am working on a project based on AT89C55. Here i am connecting sensors, switches to controller through optocoupler[MCT2E] & buffer[74LS244].Design attached with this thread.Plz check & suggest me on follwing problem.
Whenever i press the PB it gives 1.8 Vdc on buffer's i/p pin instead of which it should give 0 Vdc , So that same should reflect at buffer's o/p pin.But here buffers o/p pin always give 4 Vdc. If i check this by removing buffer IC then it gives correct result. Wat could be the problem?
I have added RC for removing key debounceing effect.
Plz give ur valuable suggestion.........i stuck up at this point & cant go ahead.
Thnks.
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