📖 From An Introduction To Microprocessor 8085 • 12. Direct Memory Access Controller: 8257 • 16 questions available
Practice MCQs for Programming of 8257. Test your knowledge with carefully crafted questions across easy, medium, and hard difficulty levels.
🔄 Last updated: 2026-07-30
Q1. A peripheral requests a block transfer of 256 bytes using the 8257 DMA controller. Which register must be loaded with the value 256 to specify the number of bytes to transfer?
💡 Difficulty: easy | ✅ Correct: B
Q2. The CPU sets the address register of channel 2 to 0x2000 and programs the count register for 1024 bytes. After the DMA block transfer completes, what value will the address register contain?
💡 Difficulty: medium | ✅ Correct: C
Q3. Two devices share channel 1 using daisy‑chaining. Device A requests 300 bytes first, then Device B requests 500 bytes. The controller is programmed with a count of 800 bytes. Which device will finish its transfer first?
💡 Difficulty: hard | ✅ Correct: A
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