📝 Programming of 8253 in mode 4: Software Triggered Strobe

Q1. Which mode of the 8253 timer is designated as Software Triggered Strobe?

💡 Difficulty: easy | ✅ Correct: C

Q2. Why must the gate input be held high for the entire counting cycle when using mode 4?

💡 Difficulty: medium | ✅ Correct: A

Q3. A system requires a 10‑ms delay followed by a 5‑ms pulse on an external device. Using channel 0 in mode 4 for the delay and channel 1 in mode 4 for the pulse, both driven by a 500 kHz clock, which sequence of count values (in decimal) should be loaded to achieve the required timing?

💡 Difficulty: hard | ✅ Correct: D