advanced audio production
a PLD-based C64 SID emulation
  This is a setup of my DDS-based sound generation used in my PLD-ORGAN 2003.
The sound module is changed that way that it emulates the famous SID in the Commodore 64.

The fundamental waves are SINE, SQUARE and TRIANGLE + SAWTOOTH.
Filtering and analog behaviour is included too to tweak the sound.

Also a simple version of the distortion module is integrated.

The R2R-DAC has been replaced in order to use PDM-output with S3.

PLD organ SID organ
Clock Frequency 20 MHz 25 MHz
Master Tones 12 12
Octaves 6 6
Tones 72 72
Keyboard 72  
Tuning balanced / pure balanced
Wave Forms 4 4
Phase Res 8 Bits 10 Bits
Amplitude Res 8 Bits 8 Bits
AD - Conversion real R2R virtual
DAC OUT 12 Bits 1 Bit PDM
Octaves 6 6
Registers 2 2
Modules 18

The design has been done for Xilinx XC4000 and was ported to a new Spartan 2.

C64-SID-Sound Example

See the FPGA-platform for details:

FPGA Audio DSP Platform
Analog Organ with programable devices
4 channel sound generation
Digital n-Bit Tone Generation Module
virtual R2R- Digital-to-Analog Conversion

base frequencies for electronic SID emulation organ
frequency setup table

For more information, see the former approach

PLD-based Sound Generation for DIY organ


© 2003 Jürgen Schuhmacher