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📝 Read/ Write Logic of 8257

📖 From An Introduction To Microprocessor 8085 • 12. Direct Memory Access Controller: 8257 • 12 questions available

Practice MCQs for Read/ Write Logic of 8257. Test your knowledge with carefully crafted questions across easy, medium, and hard difficulty levels.

🔄 Last updated: 2026-07-30

2
Easy Questions
6
Medium Questions
4
Hard Questions

📝 Sample Questions

Q1. What supply voltage is required for the Intel 8257 DMA controller?

🔹 A. +5 V
🔹 B. +12 V
🔹 C. +3.3 V
🔹 D. +9 V

💡 Difficulty: easy | ✅ Correct: A

Q2. How does the 14‑bit count field in the 8257 determine the maximum transfer size for a channel?

🔹 A. It limits transfers to 16 KB
🔹 B. It limits transfers to 2^14 = 16384 bytes
🔹 C. It limits transfers to 2^14 - 1 = 16383 bytes
🔹 D. It limits transfers to 14 bytes

💡 Difficulty: medium | ✅ Correct: B

Q3. A DMA transfer is programmed with start address 0x4000 and count 0x0FFF (4095 bytes). The 8257 operates in auto‑initialize mode, reloading the count after each block of 1024 bytes. How many block transfers will occur before the count reaches zero?

🔹 A. 3
🔹 B. 4
🔹 C. 5
🔹 D. 6

💡 Difficulty: hard | ✅ Correct: A

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🔗 Related Topics

📝 Block Diagram of 8257📝 DMA Channels of 8257📝 Data Bus Buffer of 8257📝 Control Logic of 8257📝 Mode Set Register of 8257
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