Features

Assembly Language Support

Assembly Language Support

Full support for traditional FV-1 assembly programming:

πŸ“ Syntax Highlighting

Complete syntax highlighting for .spn files and the full FV-1 instruction set

⚠️ Real-time Diagnostics

Errors and warnings appear as you type, with comprehensive error messages

πŸ’‘ Hover Information

Detailed documentation for instructions, registers, and memory locations

πŸ”— Go to Definition

Use Ctrl+Click to navigate to user-defined symbols throughout your code

βœ“ Built-in Assembler

Compile your assembly directly in VS Code with full error reporting

Visual Block Diagram Editor

Visual Block Diagram Editor

Create FV-1 programs visually without writing assembly code:

🎨 Drag-and-Drop Palette

Organized blocks in categories: I/O, Control, Gain/Mixing, Filters, Effects, and more

⚑ Real-time Compilation

See compilation results and resource usage instantly as you build

πŸ” Live Error Checking

Connection validation and resource tracking in real-time

πŸ“Š Resource Monitor

Visual feedback on instruction count, register usage, and delay memory

🧠 Code Optimizer

Automatically optimizes generated assembly to save program space

🎯 Direct Programming

Program your diagram directly to a pedal slot with one keystroke

πŸ“ Start from a Template

Begin a new diagram from a published effect instead of a blank canvas. Templates are browsed by category and fetched from the Audiofab effects repository, so the list grows without needing an extension update.

Pedal Simulator and Bank Management

Pedal Simulator

The integrated Pedal Simulator provides a highly interactive, 3D pedal UI for testing your code and managing your Easy Spin pedal’s program bank:

🎧 Audio Monitor

Listen to your effect in real-time with built-in or custom stimulus files.

🎚️ Interactive Controls

Real-time control of your pedal’s knobs and bypass switch via a highly user-friendly interface.

πŸ“‚ Visual Bank Editor

Manage all 8 program slots with an intuitive drag-and-drop interface.

🎯 Drag-and-Drop Assignment

Drag .spn or .spndiagram files directly into bank slots.

πŸ”„ Mix and Match

Combine assembly and block diagram programs in a single bank.

βš™οΈ Batch Programming

Program individual slots or the entire bank at once to your Easy Spin hardware.

πŸ“₯ Read from Pedal

Pull the programs already on your pedal back into a bank. Each one is disassembled to a .spn file you can edit and re-program; empty slots are left unassigned.

🏷️ Live Pot Labels

The knob labels on the pedal graphic name what each pot actually controls in a block diagram, and update as you re-wire it. This works for a .spndiagram on its own as well as for a bank slot, and follows the signal through Smoothers and other control shaping blocks β€” so a pot feeding a delay through a smoother reads Delay Time, not the name of the smoother’s input. A bank’s own control names, if it has them, win.

πŸ’Ύ Export to HEX

Save your bank as Intel HEX for archival or use with other programmers. Unassigned slots are left out of the file, so flashing it won’t disturb those slots on the pedal.

Low-Level Debugging

Debugger Simulator

For advanced troubleshooting, the low-level Debugger provides full access to internal state:

πŸ“ˆ Multi-trace Oscilloscope

Visualize any register or symbol with logarithmic zoom (1ms to 1s).

πŸ’Ύ Delay Memory Map

Visual representation of delay RAM usage and pointer movement.

πŸ”΄ Live Debugging

Set breakpoints, step through instructions, and inspect variables live.

Quick Actions Sidebar

Convenient access to common tasks:

✨ Create new block diagram ✨ Backup entire pedal to HEX

(Banks are created in the Pedal Simulator β€” drop a file onto a slot, or use the + button on an empty one.)

Quick Actions Sidebar

Hardware Programming

Direct integration with the Audiofab USB Programmer:

πŸ”Œ Program to any slot (1-8) on your Easy Spin pedal

βœ“ Automatic verification of written data

πŸ’Ύ Backup entire pedal to Intel HEX format

πŸ“‚ Load HEX files to EEPROM

πŸ’Ύ Export banks to HEX for use with other tools or archival

Code Optimization Levels

The block diagram compiler features a configurable three-level optimization system to balance code size and complexity:

Level 0 (None)

All blocks remain isolated with no cross-block optimizations applied.

Level 1 (Standard)

  • Accumulator Forwarding: Eliminates redundant wrax/rdax pairs between blocks

  • Register Pruning: Removes unused register assignments

Level 2 (Aggressive) - Default

Includes all Level 1 optimizations plus: - Dead Store Elimination: Removes wrax instructions whose registers are never read - Section Flattening: Collapses Input/Main/Output sections into optimized topological order - Inline Comments: Block comments are inlined for visibility in flattened execution mode

All Levels (always applied):

  • Disconnected Output Pruning: Output ports with no downstream connection never allocate a register, saving register space at the source

  • Register Renumbering: After all passes complete, surviving register declarations are compacted sequentially from REG0 upward, eliminating gaps

Note

Register and memory limits are enforced after optimization, not before. The compiler can temporarily exceed hardware limits during code generation and still succeed if the optimizer brings totals back within bounds. The register count (32) and delay memory size (32,768 words) are fixed by the FV-1 instruction encoding; only program size is configurable, via fv1.hardware.progSize.

Note

Optimization levels are required to be functionally identical β€” level 1 and level 2 must produce the same audio as level 0, only with fewer instructions. This is enforced automatically across every block and parameter setting, so a higher level can never change how a patch sounds.

Configure optimization level in VS Code settings under fv1.optimizationLevel to experiment with different tradeoffs between code size and readability.

Supported Blocks

The extension includes a comprehensive library of effects and utilities:

Inputs/Outputs

Hardware ADC and DAC routing

Control

Potentiometers, Constants, Envelope Follower, Smoother, Scale/Offset, Power curve shaping, Invert, Ramp / Sin-Cos / Entropy LFOs, Tremolizer

Gain/Mixing

2:1, 3:1, 4:1 and Stereo 2:1 Mixers, three Crossfade laws, Volume, Gain Boost

Filter

1-pole Low/High-Pass, 2-pole State Variable (SVF), Shelving Low/High-Pass, Auto-Wah, BBD Bucket Loss

Effects - Delay

Simple Delay, Three-Tap Delay, Eight-Tap Delay, MN3011 Multitap BBD Delay

Effects - Modulation

Chorus, 4-Voice Chorus, Flanger, Phaser, Harmonic Tremolo, Organ Synth, Guitar Synth

Effects - Pitch

Pitch Shift, Octave Up & Down, Sub-Octave Synth, Pitch Offset and Dual Pitch Offset (Hilbert)

Effects - Reverb

Plate, Spring, Room, Simple, Shimmer and Ducking reverbs, Spectral Smear, plus the raw building blocks: Allpass (cascaded diffusers) and Chirp (dispersive all-pass chain for spring-style β€˜sproing’)

Effects - Lo-Fi

The Bit-Mangler, Chip Tune, Tape Degrader, Micro-Stutter

Other

Fixed and Adjustable Sine Tone Generators

Note

Many blocks are ported from the excellent SpinCAD Designer.