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783 : basic_national_anthem_buzzer

Author: Eren Kaçmaz

Description: Plays the Turkish National Anthem as a square-wave melody on a piezo buzzer

Clock: 50000000 Hz

How it works

basic_national_anthem_buzzer is a digital melody player that outputs the Turkish National Anthem (İstiklâl Marşı) as a square-wave audio signal. A piezo buzzer connected to uo_out[0] will play the melody.

Architecture

The design consists of five main blocks:

Prescaler (9-bit): Divides the 50 MHz input clock by 512, producing a ~97.6 kHz internal tick used by all other blocks.
Tone Generator (8-bit variable divider): Divides the prescaler tick by a note-specific value to produce a square wave at the correct musical pitch. For example, the note A4 (440 Hz) uses a divider of 111: 97656 / (2 × 111) ≈ 440 Hz.
Tempo Counter (14-bit): Further divides the prescaler tick to produce a ~6 Hz tempo tick (~168 ms period), which controls how long each note is held.
Note Sequencer: A 6-bit address counter steps through the melody ROM. Each note has a programmable duration measured in tempo ticks. When the duration expires, the sequencer advances to the next note.
Melody ROM (combinational logic): Stores 90 note entries encoding the first two stanzas of İstiklâl Marşı in E minor (based on Osman Zeki Üngör's arrangement at 120 BPM). Each entry contains a 4-bit note code and a 4-bit duration value.

Supported Notes

B3, C4, D4, D♯4, E4, F4, F♯4, G4, G♯4, A4, A♯4, B4, C5, D5, E5, and REST.

How to test

Connect a piezo buzzer (or small speaker) between uo_out[0] and GND through a 100 Ω resistor.
Optionally connect an LED with a 330 Ω resistor to uo_out[1] to see the "playing" indicator.
Apply power and release reset — the melody starts playing automatically.
Toggle ui_in[0] (rising edge) to restart the melody from the beginning.
Set ui_in[1] HIGH to enable loop mode (melody repeats continuously).
The current note address is visible on uo_out[7:2] for debugging.

External hardware

1× Piezo buzzer or small 8 Ω speaker
1× 100 Ω resistor (in series with buzzer on uo_out[0])
1× LED + 330 Ω resistor (optional, for playing indicator on uo_out[1])
1× Push button (optional, for restart on ui_in[0])
1× DIP switch or jumper (optional, for loop mode on ui_in[1])

#	Input	Output
0	start / restart button	square-wave audio output
1	loop mode (1=repeat, 0=once)	playing indicator LED
2		note address bit 0
3		note address bit 1
4		note address bit 2
5		note address bit 3
6		note address bit 4
7		note address bit 5

Input

Output

Bidirectional

start / restart button

square-wave audio output

loop mode (1=repeat, 0=once)

playing indicator LED

note address bit 0

note address bit 1

note address bit 2

note address bit 3

note address bit 4

note address bit 5

Chip location

783 basic_national_anthem_buzzer