HARDWARE LAB 17 · PROGRAMMABLE SOUND GENERATOR
PROGRAM SOUND WITH COUNTERS
Write three 10-bit tone dividers and one 15-bit noise generator, then inspect the counters, register bytes, channel waveforms, spectrum, and analog sum.
MASTER CLOCK3.579545 MHzTONE 1261.4 HzNOISE SHIFT3.50 kHz
FIVE-TRACE LOGIC SCOPE
CAPTURINGCHANNELS + SUMMING NODE
WINDOWED DFT
OUTPUT SPECTRUM
YELLOW MARKERS = TONE FUNDAMENTALSCOUNTERS + FLIP-FLOPS
| Channel | Divider | Counter now | Output | Frequency |
|---|---|---|---|---|
| TONE 1 | 428 | 234 | LOW | 261.4 Hz |
| TONE 2 | 340 | 302 | HIGH | 329.0 Hz |
| TONE 3 | 285 | 217 | HIGH | 392.5 Hz |
| NOISE | ÷1024 | 0.722 | LOW | 3.50 kHz |
LATCH / DATA BYTES
| Register | Hex write | Bus bits |
|---|---|---|
| TONE 1 | 0x8C 0x1A | 10001100 00011010 |
| VOL 1 | 0x92 | 10010010 |
| TONE 2 | 0xA4 0x15 | 10100100 00010101 |
| VOL 2 | 0xB4 | 10110100 |
| TONE 3 | 0xCD 0x11 | 11001101 00010001 |
| VOL 3 | 0xD6 | 11010110 |
| NOISE | 0xE1 | 11100001 |
| VOL N | 0xFF | 11111111 |
FROM CPU BYTE TO SPEAKER CURRENT
- 018-BIT BUS WRITELatch selects one of eight internal registers.
- 02÷16 CLOCK SCALERFeeds three reloadable 10-bit tone counters.
- 03FLIP-FLOPS + LFSRCreate square waves and periodic or white noise.
- 042 dB ATTENUATORSFour independent 4-bit level controls; code 15 is off.
- 05ANALOG SUMMERCombines all four channels at one audio output pin.