Assignment 5 completed

notes/work-summary-2026-04-15-v2.md

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+# Assignment 5
+
+## #Overview
+This assignment implements a simple music player using the **PC speaker (PCSPK)** and the **Programmable Interval Timer (PIT)**.  
+Songs are played by generating frequencies and controlling timing between notes.
+
+---
+
+## #HowItWorks
+
+### #PCSpeaker
+The PC speaker is controlled through **port `0x61`**:
+- Bits 0 and 1 enable/disable sound output
+
+---
+
+### #PIT
+The PIT is used for:
+
+#### #SoundGeneration
+- Channel 2 generates square wave audio
+- Frequency is set using:
+
+divisor = PIT_BASE_FREQ / frequency
+
+
+#### #Timing
+- Channel 0 runs at ~1000 Hz
+- A tick counter is incremented via interrupts
+- `SleepInterrupt()` is used for accurate note timing
+
+---
+
+## #Implementation
+
+### #Playback
+Each note contains:
+- Frequency (Hz)
+- Duration (ms)
+
+Playback works by:
+1. Setting frequency with `PlaySound()`
+2. Waiting using `SleepInterrupt()`
+3. Stopping sound with `StopSound()`
+
+Rests are handled using `R = 0`.
+
+---
+
+## #Challenges
+
+### #Timing
+Busy-wait delays caused incorrect timing.  
+This was solved by using interrupt-based sleeping.
+
+### #QEMU
+QEMU has limited PC speaker support:
+- Fast note changes sound unclear
+- Songs degrade at high speed
+
+---
+
+## #Adjustments
+
+To improve playback clarity:
+
+duration = original_duration * 2
+
+
+This slows down the songs and makes notes more distinguishable.
+
+---
+
+## #Conclusion
+
+The system successfully:
+- Generates sound using the PC speaker
+- Uses PIT for timing and frequency control
+- Plays songs with multiple notes
+
+Limitations in QEMU affect sound quality, but the implementation itself works as i