8085 MICROPROCESSOR
FEATURE OF 8085
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Address lines
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Data lines
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Multiplexed lines
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All the above
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Detailed explanation-1: -Pins 12 to 19 of 8085 are AD0 – AD7 which is the multiplexed address-data bus. Multiplexing is done to reduce the number of pins of 8085. Lower byte of address (A0 – A7) are available from AD0 – AD7 (pins 12 to 19) during T1 of machine cycle.
Detailed explanation-2: -These eight pins are collectively called AD7-0. They are called basically “Address Data”. When the 8085 desires to send out 8-bit information, it sends it out on these same pins.
Detailed explanation-3: -Answer: Explanation: 8085 microprocessor have 16 bit address bus but its lower order bit multiplexed with 8 bit data bus (as 8085 has 8 bit data bus) to reduce number of pins so AD7-AD0 is bidirectional, whereas higher order bit only carries address so it unidirectional.
Detailed explanation-4: -AD0-AD7 carries low order byte data and AD8AD15 carries higher order byte data. During the first clock cycle, it carries 16-bit address and after that it carries 16-bit data.
Detailed explanation-5: -Why the lower byte address bus (A0 – A7) and data bus (D0 – D7) are multiplexed? Ans. This is done to reduce the number of pins of 8085, which otherwise would have been a 48 pin chip. But because of multiplexing, external hardware is required to demultiplex the lower byte address cum data bus.