Identify the data width and interface style of the Intel 8085A: what kind of CPU is the 8085A in terms of word size and data transfer (serial vs. parallel)?
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A16-bit parallel CPU
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B8-bit serial CPU
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C8-bit parallel CPU
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Dnone of the above
Answer
Correct Answer: 8-bit parallel CPU
Explanation
Introduction / Context:Classifying a microprocessor by word size and data movement style helps predict performance, instruction set density, and peripheral interfacing. The Intel 8085A is a classic starter CPU in many curricula and labs.
Given Data / Assumptions:
- 8085A is historically known as an 8-bit microprocessor.
- It communicates with memory and peripherals using parallel buses.
- Address bus and data bus widths are standard features in its datasheet.
Concept / Approach:An 8-bit CPU processes 8-bit data in the ALU in a single cycle, with larger values handled across multiple cycles. A parallel interface transfers multiple bits simultaneously across data/address lines, enabling higher throughput compared to serial transfer.
Step-by-Step Solution:
Identify ALU width → 8 bits for 8085A.Identify bus organization → 8-bit data bus (multiplexed AD0–AD7), 16-bit address capability via demultiplexing.Confirm transfers occur in parallel on the bus lines.Therefore, the 8085A is an 8-bit parallel CPU.Verification / Alternative check:Typical kits show address/data bus lines on 8085 trainers; timing diagrams indicate parallel bus transactions.
Why Other Options Are Wrong:
- 16-bit parallel: describes CPUs like 8086 (internally 16-bit).
- 8-bit serial: contradicts 8085A's parallel bus architecture.
- None of the above: incorrect because option C is accurate.
Common Pitfalls:Confusing “address bus width” (16-bit) with “data width” (8-bit). The CPU is still categorized as 8-bit.
Final Answer:8-bit parallel CPU