From b5fc72f5319f1480c2f04e6a92076ee13a8a32fe Mon Sep 17 00:00:00 2001
From: Timo Niemann <timo.niemann@siemens.com>
Date: Thu, 4 Jun 2026 11:53:20 +0200
Subject: [PATCH] added minimal explaining readme

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+# PicoSDKandFreeRtos
+
+Minimal Raspberry Pi Pico 2 (RP2350) project running FreeRTOS, plus a small
+.NET host tool to measure USB-CDC round-trip latency.
+
+## Firmware
+
+The firmware exposes a simple ping protocol over USB-CDC. The host sends:
+
+```
+<id>:ping\n
+```
+
+and the Pico replies:
+
+```
+<id>:PONG!\n
+```
+
+### Build & flash
+
+Open the folder in VS Code with the **Raspberry Pi Pico** extension, then:
+
+1. If not prompted directly: Command Palette -> **Raspberry Pi Pico: Import Pico Project**
+2. Command Palette -> **Raspberry Pi Pico: Run Pico Project (USB)**
+
+Required tooling (auto-installed by the extension):
+
+- Pico SDK 2.2.0
+- ARM GCC toolchain `14_2_Rel1`
+- `picotool` 2.2.0-a4
+- Ninja, CMake
+
+## Host tool: `response_tester.cs`
+
+A .NET 10 file-based app that bursts ping commands over the serial port and prints per-command and average round-trip latency.
+
+### Run
+
+Requires .NET 10 SDK.
+
+```bash
+dotnet response_tester.cs
+```
+
+Adjust `portName` (default `COM30`) inside the file if needed.
+
+## Troubleshooting
+> Raspberry Pi Pico: Run Pico Project (USB) not working
+- try **Raspberry Pi Pico: Compile Pico Project** 
+- hold `BOOTSEL` while connecting the Pico
+- a new drive should be mountable
+- move the *.uf2 file from ./build onto the new drive
+
+> COM-Port
+- On Windows the Pico typically appears as `COMx` (check Device Manager).
+- On Linux it appears as `/dev/ttyACM0` (or `ACM1`, ...).
+- On macOS it appears as `/dev/tty.usbmodem*` or `/dev/cu.usbmodem*`.
+- Update `portName` in `response_tester.cs` accordingly.
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