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+---
+slug: debug
+title: Debug
+---
+import Image from '@theme/IdealImage';
+
+# Debug
+
+Most of the code is possible to debug with Zephyr logging functions like `LOG_INF`, `LOG_HEXDUMP_INF` and others.
+
+However, sometimes it is necessary to do proper low-level hardware debugging with single stepping and memory view.
+
+You can easily do that with [**nRF Connect for VS Code**](https://marketplace.visualstudio.com/items?itemName=nordic-semiconductor.nrf-connect) extension in your VSCode.
+
+![](debug/debugging.png)
+
+
+## Install
+
+In VSCode hit `Ctrl` + `P` and type `ext install nordic-semiconductor.nrf-connect`, hit enter.
+
+## Debugging
+
+1. Open the **nRF Connect for VS Code** extension, click `Open Existing Application` and choose a folder of the application, where you usually call `west build`.
+
+![](debug/open-existing-application.png)
+
+2. In the project `prj.conf` comment with `#` or **remove `CONFIG_CTR_BLE=y`. BLE is timing sensitive and when enabled, debugging don't work correctly.**
+
+![](debug/disable-ble.png)
+
+3. In the left panel in **Applications** section, click **+ Add build configuration**
+
+4. In the **Board** option select `chester_nrf52840`. Set **Optimization level** to **Optimize for debugging (-Og)**. Then click **Build Configuration** button on the bottom. The project is built.
+
+5. In the left panel in **Actions** click on the **Debug** and start debugging your code.
+
+:::warning
+
+Do not use **Erase board** or any other similar option. CHESTER uses UICR region to save serial number and communication keys. If you erase that, you will need to recover [**PIB data**](../developer-tools/command-line-tools.md#product-information-block).
+
+For erasing the board use [**HARDWARIO CLI**](../developer-tools/command-line-tools.md) erase command which keeps the UICR regions.
+
+:::
+
+## Shell over RTT
+
+In the **Connected devices** left panel, you can open RTT communication with the device. It uses channel 0 which is Zehpyr shell. You can type commands to the terminal. The second RTT channel with logs is not displayed here.
+
+![](debug/rtt-shell.png)
+
+## Threads
+
+In the **NRF DEBUG** tab you can inspect threads and memory.
+
+![](debug/nrf-debug.png)
+
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diff --git a/sidebars-chester.js b/sidebars-chester.js
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+++ b/sidebars-chester.js
@@ -126,6 +126,7 @@ const sidebars = {
         'firmware-sdk/installation-on-windows',
         'firmware-sdk/installation-in-virtualbox',
         'firmware-sdk/build-and-deploy',
+        'firmware-sdk/debug',
         'firmware-sdk/applications',
         'firmware-sdk/samples',
         'firmware-sdk/application-customization',