The Yamaha YMZ284 is a 16-pin chip which has the same function and register-level interface as the General Instruments AY-3-8910. The YMZ284, though, is smaller and has a simpler bus interface. Unlike the AY-3-8910, it is write-only; register contents may not be read back.
This Arduino sketch tests a YMZ284 chip by setting up some initial configuration and generating sounds. The Arduino's ADC (analog-to-digital converter) is used, along with a pot, to control the sound generator.
The ATmega328 on the Arduino is set up to generate a 2MHz clock on Arduino Pin 3 (ATmega328 Pin 5). This is the 16MHz Arduino clock frequency divided by 8.
| Signal | Arduino Pin | ATmega328 Pin | YMZ284 Pin | Notes |
|---|---|---|---|---|
| RxD | 0 | PORTD0 pin 2 | Unused | |
| TxD | 1 | PORTD1 pin 3 | Unused | |
| CS | 2 | PORTD2 pin 4 | /CS pin 2 | Chip Select, active LOW |
| CLK | 3 | PORTD3 pin 5 | ΦM pin 7 | Main clock, 2MHz |
| WR | 4 | PORTD4 pin 6 | /WR pin 1 | Write Enable, active LOW |
| A0 | 5 | PORTD5 pin 11 | A0 pin 3 | Address/Data Select |
| D0 | 6 | PORTD6 pin 12 | D0 pin 16 | CPU interface data bus (LSB) |
| D1 | 7 | PORTD7 pin 13 | D1 pin 15 | CPU interface data bus |
| D2 | 8 | PORTB0 pin 14 | D2 pin 14 | CPU interface data bus |
| D3 | 9 | PORTB1 pin 15 | D3 pin 13 | CPU interface data bus |
| D4 | 10 | PORTB2 pin 16 | D4 pin 12 | CPU interface data bus |
| D5 | 11 | PORTB3 pin 17 | D5 pin 11 | CPU interface data bus |
| D6 | 12 | PORTB4 pin 18 | D6 pin 10 | CPU interface data bus |
| D7 | 13 | PORTB5 pin 19 | D7 pin 9 | CPU interface data bus (MSB) |
| /IC pin 8 | Initial Clear, active LOW | |||
| SO pin 5 | D/A Converter Output (sound) | |||
| Vdd | 5V | VCC pin 7/21 | VDD pin 4 | +5V Power Supply |
| Gnd | Gnd | GND pin 8/22 | GND pin 6 | Ground |
