EmbedSim Debug

Source-level debugging of embedded firmware running in a circuit simulator, driven over the simulator's Remote Debug Monitor (TCP). It spawns a small debug-adapter (DAP server) and gives you normal VS Code debugging — breakpoints, stepping, call stack, variables, memory.

Current target: Microchip PIC firmware in the Proteus VSM simulator. Supported device: PIC18F45K22 (the bundled debug-executive template is for this part; other PICs need their own). Build your project with the MPLAB extension pack, then debug it here — a distinct debug type (embedsim) keeps it clear of MPLAB's own debugger (mplab-core-da).

Unofficial. Not affiliated with or endorsed by Labcenter Electronics (Proteus, VSM) or Microchip Technology (MPLAB, PIC). Those names are used only to describe compatibility. See NOTICE for the debug-executive caveat.

How it works

VS Code  --DAP/stdio-->  embedsim adapter  --RDM/TCP 8000-->  simulator

On launch the adapter parses DWARF from the MPLAB-built debug ELF (line table + globals), builds the device debug image, loads it into the simulator, sets breakpoints, runs, and maps halts back to source.

Prerequisites

• The circuit simulator running your design with its Remote Debug Monitor enabled, listening on 127.0.0.1:8000.
• Your project built for debug with MPLAB (XC8) → a debug .elf.
• A device debug-executive template (see NOTICE). The bundled build expects one for PIC18F45K22; for other devices, supply your own via embedsim.debugExecTemplate.

Use

1. Build your firmware (debug) with MPLAB.
2. Start the simulator with the Remote Debug Monitor on.
3. Open the Tools sidebar → EmbedSim Debug → Start Debugging, or pick "EmbedSim: Debug" in Run and Debug (F5). The ELF is auto-located.

launch.json

{
  "type": "embedsim",
  "request": "launch",
  "name": "EmbedSim: Debug",
  "program": "${command:embedsim.findElf}",  // or an explicit .elf path
  "host": "127.0.0.1",
  "port": 8000,
  "stopOnEntry": true
}

Settings

• embedsim.adapterPath — override the debug-adapter executable.
• embedsim.debugExecTemplate — override the device debug-executive template.

Features

Source-line breakpoints (DWARF), continue / step in / step over / step out (source-line granular), call stack with source mapping, CPU register (PC) + Globals view with live values, read/write data memory.