Without I2S enabled there is no run time overhead added in the critical loop. Just call start_with_i2s(.) instead of start(.) and pass the I2S pin group as an argument. Output sample rate is ~159kHz for I2S and double that for analog output. I used the PMOD I2S board with the P2-EVAL and managed to get something working with it and can hear the music playing in the jukebox demo. I've been able to patch this code to work with a CS4344 I2S DAC. Compile with flexspin -2 megajuke.c -D_BAUD=2000000.Open megajuke.c and edit the pin constants near the top.Have the latest flexspin/flexprop (5.4.3) installed.SD code is probably not quite thread safe) The MEGA JUKE program streams register dumps from a file, using the 9P server in loadp2 (in theory, replacing _vfs_open_host with _vfs_open_sdcard should make it run from SD card, too, but in practice it hangs after reading the track text, IDK why. Script for computing the LFO FM lookup table Script for computing the EG rate lookup tables Copy a VGM file from the tunes directory and load it!Įxample/test that plays a note normally and then with all 8 SSG-EG modes VGI patch files used by the Spin API example

Add your own favorite tunes!Įxample that plays a weird little tune using the Spin API and VGI patch files (Note: the spectrograph in these is not running on the P2, it's just there so it's more than a still image) What's included File name Still orders of magnitude better than those silly AtGames units, haha Some instruments sound a little off, but maybe I'm just going insane. (Too low clock speed -> low and/or inconsistent pitch) Requires at least 250 MHz P2 clock to run properly. PSG sound is somewhat aliased due to relatively low update rate (~53 kHz).This causes slight clicking on certain envelope rates and other artifacts.

Bonus: SEGA PSG (SN76489 variant) emulation!Įnvelope generators are updated at 1/12 the real rate (~1.5kHz instead of ~18 kHz).

Mostly supports CH3 special mode (rate scaling doesn't account for it).

Channels are not mixed, but multiplexed onto the DAC, like in the real chip.

All 24 oscillators updated at the same rate as the real chip (~53 kHz).

6 channels of 4-operator phase-modulation synthesis.

This is an emulation of the Yamaha 'OPN2' YM2612 FM synth chip that runs in one P2 cog.

Sega genesis sound chip emulator