INTRODUCTION TO MICROPEOCESSOR
MODEL OF MICROPROCESSOR
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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PORT0
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PORT1
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PORT2
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PORT3
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Detailed explanation-1: -Port 2. P2 is similar to P0 when the external memory is used. Pins of this port occupy addresses intended for the external memory chip. This port can be used for higher address byte with addresses A8-A15.
Detailed explanation-2: -While connecting an 8051 to external memory, Port 0 can provide both address and data. The 8051 microcontroller then multiplexes the input as address or data in order to save pins. Dual role of Port 2 − Besides working as I/O, Port P2 is also used to provide 16-bit address bus for external memory along with Port 0.
Detailed explanation-3: -Port 2 is designated as A8-A15, indicating its dual function. When 8051 is connected to external memory, P2 is used for the upper 8 bits of the 16-bit address and it cannot be used for I/O.