Single Chip Writing Puzzles

platform: STC51 MCU 

 

Puzzle 1: codes set P1^0=0, while P1^0 connects in wire with a outer 5 voltage source.

Question:  What is P1^0's output?

 

Experiment result: +5V

 

outer wins!

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Puzzle 2: codes set P1^0=0, P1^1=1, and they are connected by an outer wire.

Question: What is P1^0's output?

 

Experiment result: 0v.

 

zero wins!

 

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This tests different sources write 0/1 to the same address. What is the output?

 

Normally,  register listens to outer guy.