add readme debug print

diff --git a/readme.md b/readme.md
index 3fd7904ac08c8addc1cf5c1c3f77911d452fa242..f2c5a40041d518c1374678e5e15efdd4ad1ac71a 100644 (file)
--- a/readme.md
+++ b/readme.md
@@ -88,13 +88,16 @@ cmake -DRUN_TESTS=on ..
 make
 ```
 
-build with debug symboles
+build with debug symboles and debug prints
 
 ```bash
 cmake -DCMAKE_BUILD_TYPE=DEBUG ..
 make
 ```
 
+It can debug print with level 1 to 6 with envorioment variable
+KDS_S2000W_NET_DEBUG=<1-6>
+
 ## Architecture
 
 The diagram is created with Markdown Preview Mermaid Support plugin for VSCode.