ZX Spectrum Sound: From Beeper to AY-3-8910
ZX Spectrum System Tour: Sound
The ZX Spectrum's sound capabilities are explored, covering the 1-bit beeper and the AY-3-8910 chip. The article details using the ROM's BEEPER routine for precise tones, then implementing a custom oscillator with cycle-exact timing, overcoming memory wait states by relocating code and using a global variable. It concludes with a program that plays a C-major scale.
The problem, as it turns out, is that the Spectrum’s video circuitry needs to fetch pixel and color data from the RAM, and it can force the CPU to wait while it does those things.