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https://github.com/Yevgeniy-Olexandrenko/avr-ay-board

The replacement board for the AY-3-8910/AY-3-8912/YM2149F sound chip. Compatible with https://www.avray.ru project firmware.
https://github.com/Yevgeniy-Olexandrenko/avr-ay-board

arduino atmega avr avr-ay ay-3-8910 ay-3-8912 chip chiptune psg retro sound ym2149f zx-spectrum

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The replacement board for the AY-3-8910/AY-3-8912/YM2149F sound chip. Compatible with https://www.avray.ru project firmware.

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README 

        
# Introduction



AY-3-8912 Emulator is a replacement board for the famous AY-3-8910/AY-3-8912/YM2149F sound chip of the ZX-Spectrum 128 and others. Based on the schematic and firmware from [AVR-AY project](https://www.avray.ru), [discussion on ZX-PK.ru](https://zx-pk.ru/threads/10510-emulyator-ay-8910-na-atmega.html) and [Turbo Sound schematic](https://github.com/andykarpov/turbosound28p) resources.



![Photo](/hardware/v1.3/AY-3-8912-Emulator-v1.3_Photo.jpg)



### Features:

- Complete chip emulation (sound generation only)

- Parallel mode write/read operations support

- Serial mode write operations support



# Usage



### Serial communication mode



Baud Rate|Data Bits|Stop Bits|Parity

-|-|-|-

57600|8|1|NONE



Registers are sent as a pair of values: register number (0-13), then register value. To synchronize, just send `0xFF` at the start of sending.



This sound chip emulator can be used in conjunction with the [AVR-AY Player](https://www.avray.ru/avr-ay-player) or [PSG Tools](https://github.com/Yevgeniy-Olexandrenko/psg-tools). You will need the most ordinary USB to serial TTL converter. Just connect `+5V`, `GND` and `TX` pins of the converter to `VCC`, `GND` and `RX` pins of this emulation device, open corrsponding `COM` port in the player/tool and start playing music.



### Parallel communication mode



...



# Hardware



The [schematic](/hardware/v1.3/AY-3-8912-Emulator-v1.3_Schematic.pdf) of the device is quite simple. The heart of the emulator is a 8-bit ATmega series microcontroller, which runs at an overclocked frequency and performs low-level simulation of the sound chip. The rest of the device is three low-pass filters with a cutoff frequency of about 20 kHz, three communication interfaces and three output audio channels with analog signal waveform.



### Serial interface



Pin|Name|Function

-|-|-

1|`GND`|Ground

2|`VCC`|Power Supply (+5V)

3|`TX`|Serial dada output (Speaker Input for AVR-AY)

4|`RX`|Serial Data Input



### Parallel interface



Pin|Name|Function|Pin|Name|Function

-|-|-|-|-|-

1|`C`|Analog Channel C|28|`D0`|Data/Address 0

2|`TEST`|*no connection*|27|`D1`|Data/Address 1

3|`VCC`|Power Supply (+5V)|26|`D2`|Data/Address 2

4|`B`|Analog Channel B|25|`D3`|Data/Address 3

5|`A`|Analog Channel A|24|`D4`|Data/Address 4

6|`GND`|Ground|23|`D5`|Data/Address 5

7|`IOA7`|*not implemented*|22|`D6`|Data/Address 6

8|`IOA6`|*not implemented*|21|`D7`|Data/Address 7

9|`IOA5`|*not implemented*|20|`BC1`|Bus Control 1

10|`IOA4`|*not implemented*|19|`BC2`|*not implemented*

11|`IOA3`|*not implemented*|18|`BDIR`|Bus Direction

12|`IOA2`|*not implemented*|17|`A8`|*not implemented*

13|`IOA1`|*not implemented*|16|`RES`|Reset (Low active)

14|`IOA0`|*not implemented*|15|`CLK`|*not implemented*



### In-Circuit Serial Programming interface



Pin|Name|Function|Pin|Name|Function

-|-|-|-|-|-

1|`MISO`|Master In/Slave Out|2|`VCC`|Power Supply

3|`SCK`|Clock|4|`MOSI`|Master Out/Slave In

5|`RES`|Reset|6|`GND`|Ground



### Hardware configuration



The default hardware configuration of the device assumes the use of an ATmega48PA microcontroller with a 27 MHz crystal resonator. According to feedbacks, it should work reliably. But you are free to use another microcontroller (ATmega8, ATmega88, ATmega168 and ATmega328) and a quartz resonator with another frequency (20 MHz, 24 MHz, 25 MHz, 28.332 MHz, 28 MHz, 30 MHz, 32 MHz and 40 MHz).



...



# Firmware



...



# References, Links and Notes



1. [Project on EasyEDA](https://easyeda.com/yevgeniy.olexandrenko/avr-ay)

2. [AVR-AY Home Page](https://www.avray.ru)

3. [Discussion on ZX-PK.ru](https://zx-pk.ru/threads/10510-emulyator-ay-8910-na-atmega.html)

4. [AY-3-8910/12 Datasheet](/datasheet/AY-3-8910-microchip.pdf)

5. [YM2149 Datasheet](/datasheet/ym2149-yamaha.pdf)

6. [ATmega48 Datasheet](/datasheet/ATmega48.pdf)