fv1emu

README

fv1emu

A simple Spin FV-1 DSP emulator written in GOLang. It has a built-in debugger for step-by-step evaluating and state inspection.

License

MIT License

Current state

Most of the reverb/delay related programs works as expected. The main issues currently is related to the LFO behaviour and the CHO RDA/SOF instruction, especially the RAMP LFO.

All programs used when testing has been compiled using the asfv1.py assembler.

The emulator has currently only been compiled and tested on Ubuntu/Linux.

No optimizations has been done so this emulator is not yet ready for robust realtime processing, yet.

Dependencies

All dependencies are listed in "go.mod"

Compiling

$ go mod download
$ go build

Usage

$ ./fv1emu -help

-bin string
	FV-1 binary file
-debug
	Enable step-debugger user-interface
-disable-24bits-clamping
	Disable clamping of register values to 24-bits but use the entire 32-bits range.
-hex string
	SpinCAD/Intel HEX file
-in string
	Input wav-file (default "input.wav")
-out string
	Output wav-file (default "output.wav")
-p0 float
	Potentiometer 0 value (0 .. 1.0) (default 0.5)
-p1 float
	Potentiometer 1 value (0 .. 1.0) (default 0.5)
-p2 float
	Potentiometer 2 value (0 .. 1.0) (default 0.5)
-pmax
	Set all potentiometers to maximum
-pmin
	Set all potentiometers to minimum
-print-code
	Print program code (default true)
-print-debug
	Print additional info when debugging
-prog int
	Which program to load for multiprogram BIN/HEX files
-reg-to-csv int
	Write register values to 'reg-<NUM>.csv'. One value per sample. (default -1)
-skip-to int
	Skip to sample number (when debugging) (default -1)
-stop-at int
	Stop at sample number (default -1)
-stream
	Stream output to sound device
-trail float
	Additional trail length (seconds)

$ ./fv1emu --in INPUT.WAV --out OUTPUT.WAV --bin ALGO.BIN 

Debugger

It is possible to step-debug an FV-1 program by using the '-debug' parameter. The debugger can be used to inspect the internal state and registers of the system. The debugger is terminal-based.

The debugger also has a simple Delay Memory inspector.

TODOs

• Calibrate the LFO with an actual FV-1 DSP.
• Get the Ramp-LFO right.
• Catch overflows within operations (the register.Clamp24Bit() function) and show warnings in the debugger.
• Test on MacOS and Windows.
• Better streaming, preferably realtime streaming.
• Realtime processing of an input-stream like another app or a microphone.
  • Add functionality for changing the POT-values at runtime.
• Export CSV/Excel tables with register values for each sample
  • Nice to visualize in external graphing programs. LFO shapes etc.
• Let the user set the external clock-speed to other frequencies than the default.
• Add scripted change-patterns to the realtime clock (like the EQD Afterneath).
• The FV-1 has internal filters. These should be emulated.
  • The AN-0001, page 5 mentions "high-pass filtering in the DAC" in the Ramp LFO program.
• Better memory-visualization
• Keep track and visualize allocated memory chunks in addition to the entire memory-map.

Links

• A test-suite for the FV-1: https://github.com/ndf-zz/fv1testing

• A Python based FV-1 assembler: https://github.com/ndf-zz/asfv1

• A search on Github for SpinASM programs: https://github.com/search?q=extension%3Aspcd

Notes

• Converting UTF-16 .spn files to UTF-8:

  $ iconv -f UTF-16LE -t UTF-8 <infile> -o <outfile>
  

• Plotting the content of a CSV register dump:

  • Execute the following script available in this repo:

    $ ./csv-plot.sh CSVFILE

• Converting a Intel HEX file to BIN:

  $ objcopy -I ihex original.hex -O binary newfile.bin