SwinSID X2 - Dual core SwinSID

    SwinSID X2 sound module is a successor of my previous C64 sound cards. It has all the best features from SwinSID SE and SwinSID2 prototype and many new enhancements. First of all the new X2 version uses two AVR MCUs thus it can emulate two SID chips with single board. This gives much more processing power (it is more than 50 times faster than c64's CPU). With dual core operation new SwinSID is enought powerfull to use more accurate emulation and mixing algorithms. Since the last release firmware was heavily improved and various bugs were fixed. It results in more clean sound with minimized aliasing effect and greatly improved SID compability.

Features

    SwinSID X2 has almost all features of original SID chip - simple waveforms, effects, filter and more. In dual core mode the polyphony was increased from standard 3 to 6 voices. There is new speciall mode to allow playing single voice with two different oscillators simultaneously and adjustable phase shift.
Soundcard has 8 various waveforms from classic shapes (pulse, sawtooth, sine) to complex and soft sounds.
If that's not enough, waveform output can be modulated by value of other oscillator resulting in simple FM synth. SwinSID X2 can be also used for high quallity 8 bit stereo sample playback instead of generating waveforms. Two cores gives 12 channels of 8 bit stereo channels with hardware mixing and voilume control
Finally, there is 16 bit digital lowpass filter with adjustable cut-off frequency and strong resonance. The filter doesn't have true SID charasteristic, but it sounds more like 8580 than 6581 with 'C64 compatible' firmware.
The SwinSID X2 waveforms was improved to match standard 8580 sound and new waves was added by using non standard waveform selection bits. That gives 8 new sounds maintaining compability with standards SID tunes.

Hardware

    In the new SwinSID X2 there are two AVRs, single DAC and address decoder. There is one firmware for dual and single core version thus the new firmware is also compatible with previous SwinSID SE board. DAC is now connected only to master core and plays its voices on left channel while slave voices on the right. Both AVRs runs with the same 24MHz integrated oscilator clock source which helps maintain stability under heavy overclocking. C64 data and addres buses of both MCUs are connected together and address decoder is used to split one CS signal into two AVRs (this requires access to external A5 addres line from C64 bus). AVR port E is used for synchronization and port A for data transfer between master and slave cores.

MIDIBox

    In mid 2007 I have started to cooperate with Thorsten Klose (creator of the MIDIBox hardware platform) to use SwinSID as a SID replacement in his MIDIBox SID module. He built SwinSID prototype and did intensive tests to check if it is usable with his other MIDI hardware. During this tests I have made several firmware updates to meet requirements. With TK help (and his scope :) I was able to fix some critical timmings which i didn't realize until he found it. He also modified MIDIBox firmware to support new SwinSID features directly from his devices. Now you can use SwinSID not only as a SID replacement but also as a simple synthesizer with nice sets of features and oldschool sounding. The board laytout for MIDIBox  platform module with SwinSID is under development by MIDIBox community and for now only SID socket replacement is supported.

Thanks

    I would like to thank all people supporting Swin SID for testing, reporting bugs and etc. Special thanks goes to Thorsten Klose - for thorough testing and help fixing serious DAC problem and thanks for Crisp for firmware testing, SID recording demos and design of the new SwinSID X2 board layout.

For more info about SwinSID X2 and supporting it send me an e-mail