door alarm

We started off by setting the first four ports of PORTB as the inputs and the latter four ports as the outputs. The first four ports are connected to the columns meanwhile the last four are connected to the rows. Moreover, as a justification for this reasoning is the fact that it is required to scan the columns for the pressed key and then scan the rows and the results will be decoded in a decoder telling us which button of the keypad was pressed. The main functionality of the keypad as mentioned earlier is to set the code. The alarm can be armed and disarmed with a standard four digit user code in our case. The master code is a step above a regular user code.

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houston security system

This does not mean that the operation can continue indefinitely without these competencies, just that they can be interrupted without completely interrupting the operation.

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