Features

Assembly Language Support

Full support for traditional FV-1 assembly programming:

📝 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
💡 Hover Information: Detailed documentation for instructions, registers, and memory locations
🔗 Go to Definition: Use Ctrl+Click to navigate to user-defined symbols throughout your code
✓ Built-in Assembler: Compile your assembly directly in VS Code with full error reporting

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
🔍 Live Error Checking: Connection validation and resource tracking in real-time
📊 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

Integrated Real-time Simulator and Debugger

Debug assembly files:

Or simulate with realtime audio:

Test your programs without hardware:

🎧 Audio Monitor: Listen to your effect in real-time with built-in or custom stimulus files
📈 Multi-trace Oscilloscope: Visualize any register or symbol with logarithmic zoom (1ms to 1s)
💾 Delay Memory Map: Visual representation of delay RAM usage and pointer movement
🔴 Live Debugging: Set breakpoints, step through instructions, and inspect variables live
🎚️ Interactive Controls: Real-time control of POT0, POT1, POT2 and Bypass during simulation

Resource Usage Tracking

Monitor your program’s resource consumption in real-time:

📌 Instructions: Visual indicator showing usage out of 128 instructions
📌 Registers: Track usage of 32 available registers
📌 Delay Memory: Monitor usage out of 32,768 words of delay RAM

Program Bank Management

Organize and deploy multiple programs to your Easy Spin pedal:

📂 Visual Bank Editor: Manage all 8 program slots with an intuitive interface
🎯 Drag-and-Drop Assignment: Drag .spn or .spndiagram files directly into bank slots
🔄 Mix and Match: Combine assembly and block diagram programs in a single bank
⚙️ Batch Programming: Program individual slots or the entire bank at once
🔄 Automatic Compilation: All files compile/assemble automatically during programming
💾 Export to HEX: Save your bank as Intel HEX for archival or use with other programmers

Hardware Programming

Direct integration with the Audiofab USB Programmer:

🔌 Program to any slot (1-8) on your Easy Spin pedal

✓ Automatic verification of written data

💾 Backup entire pedal to Intel HEX format

📂 Load HEX files to EEPROM

💾 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. All hardware limits (registers, program size, delay memory) are pulled from your VS Code settings, not hardcoded.

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: Envelope followers, Smoothers, Power curve shaping, Ramp and Sin/Cos LFOs, Tremolizers
Gain/Mixing: 2:1 and 3:1 Mixers, Multi-channel Crossfades, Volume controls
Filter: 1-pole Low/High-Pass Filters, 2-pole State Variable Filters (SVF), Shelving Filters
Effects - Delay: Simple Delay, Triple-Tap Delay
Effects - Modulation: Chorus, Flanger, Phaser
Effects - Pitch (New in v1.4.3): Pitch shifter with adjustable range, fixed pitch offset, dual offset variant, octave up/down
Effects - Reverb: Plate, Spring, Room, and Minimal reverbs
Other: Fixed and Adjustable Sine Tone Generators

Note

Many blocks are ported from the excellent SpinCAD Designer.