Update README.md

TimerOverflow · web-flow · commit d2582d202fd3 · 2021-09-09T09:19:46.000+09:00
diff --git a/README.md b/README.md
@@ -5,3 +5,6 @@ use for calculate moving average.
 - FIFO
 - can select variable size
 - hot change sampling level support
+
+# Build & Tested Environment
+- IAR C/C++ Compiler for AVR 6.11.1 (6.11.1.50453)
