PAL-1 Digital Complex Sound Generator

Introduction

The PAL-1 Digital Complex Sound Generator is an expansion board for the PAL-1 system¹, based on the Texas Instruments SN76489 digital complex sound generator² and was inspired by a Circuit Cellar project³ .

The SN76489 DCSG provides three programmable tone generators and one noise generator. Each tone generator has a frequency synthesis and attenuation section. The noise generator supports a noise source and attenuator. The three tone generators and the noise source are mixed and passed to an output buffer. As the SN76489 output pin drives a maximum of 10mA, the circuit includes a simple amplifier circuit to allow a speaker to be connected.

Acknowledgements

PAL-1 and the PAL-1 logo used with kind permission of Liu Ganning.

References

1. Liu Ganning, ‘PAL-1 Microcomputer User Manual’, 2020 http://pal.aibs.ws/assets/PAL_en.pdf [accessed 21 July 2022].
2. The Engineering Staff of TEXAS INSTRUMENTS Semiconductor Group, ‘SN76489AN’ (TEXAS INSTRUMENTS, N.D.)
3. Ciarcia, Steve, ‘Add Programmable Sound Effects to Your Computer’, Byte, 7.7 (1982), 60–72