SIDemuBoard V1.1

• 1 Cortex-M3 MCU (overclocked)
• Single SID emulation with accurate PHI2 synchronization
• 16bit (2*8bit dual PWM ~400KHz) audio output @ 44.1KHz mixing frequency
• Pseudo multi-sampling of waveform generators for seamless sound even at high frequencies
• Combined waveforms are tabularized but also pseudo multi-sampled
• Sub-sample generation before every register write
• Read-only registers (OSC3/ENV3/POTX/POTY) and last bus state on reading from write-only addresses implemented
• OSC3 and ENV3 not updated on every single clock so measurement test programs may fail but no audible differences in practice
• POTX/POTY not tested with mouse yet (I don't have any) but may work in theory
• Hard-sync and ring-modulation implemented
• 5x oversampled state variable filter with an approximated distortion model in 6581 mode
• The filter uses fixed-point arihtmetic
• 5 predefined (R2/R3/R4/R4AR/R5) and 3 optional fully configurable SID model
• SID models can be selected on-the-fly seamlessly with external buttons connected to the panel's pin header (buttons not included)
• 4 LEDs to show actual state of the 3 envelope generators and the filter cutoff frequency
• VDD and CAPs not connected so can be used in every motherboard revisions
• EXTIN not implemented

SIDemuBoard V2.1

• 2 Cortex-M4 MCUs (without overclocking) for cycle exact readback of OSC3 and ENV3 registers
• Single SID emulation with accurate PHI2 synchronization
• 16bit (2*8bit dual DAC) audio output @ 44.1KHz mixing frequency
• Pseudo multi-sampling of waveform generators for seamless sound even at high frequencies
• Combined waveforms are tabularized and brute force multi-sampled
• Sub-sample generation before every register write
• Read-only registers (OSC3/ENV3/POTX/POTY) and last bus state on reading from write-only addresses implemented
• OSC3 and ENV3 updated on every single clock so measurement test programs works just fine in most cases
• POTX/POTY not tested with mouse yet (I don't have any) but may work in theory
• Hard-sync and ring-modulation implemented
• 4x oversampled state variable filter with an approximated distortion model in 6581 mode
• The filter uses floating-point arihtmetic
• 5 predefined (R2/R3/R4/R4AR/R5) and 3 optional fully configurable SID model
• SID models can be selected on-the-fly seamlessly with external buttons connected to the panel's pin header (buttons not included)
• Voice feedback on changing SID models by external button
• 4 LEDs to show actual state of the 3 envelope generators and the filter cutoff frequency
• VDD and CAPs not connected so can be used in every motherboard revisions
• EXTIN not implemented yet but planned

~ Lóránt ~