advanced audio production
FPGA-based C64 SID emulation
  This is a special setup of my DDS-based sound generation used in my VPLD-ORGAN.
It emulates the function of the famous SID in the Commodore 64.

Unlike in the first version SID-Emulation the sound here is triggered by an internal Player using a reduced set of MIDI. It totally replaces the keyboard.
Altogther 2 channels with 4 voices each can be used in one module.

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

Also an enhanced version of the distortion module is integrated

Virtual R2R- Digital-to-Analog Conversion is used to make ose of the PDM-function.

PLD organ SID organ
Clock Frequency 25 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 2

Listen to a file with the former Xilinx XC4000:

SID-Sound Example

See the FPGA-platform for details:

FPGA Audio DSP Platform
Analog Organ with programable devices
2x4 channel sound generation
Digital 4 Bit Tone Generation Module

base frequencies for electronic SID emulation organ
frequency setup table


© 2006 Jürgen Schuhmacher