diff --git a/ch32v003/clang.mk b/ch32v003/clang.mk
index bd6ae78..abdd887 100644
--- a/ch32v003/clang.mk
+++ b/ch32v003/clang.mk
@@ -1,5 +1,8 @@
 # Use clang / llvm toolchain
-# zatim blbost
+# Zatím není podporováno - problém :
+# E: RV32I subset, only 16 general-purpose registers supported
+# v clang není korektně implementováno.
+#
 CC = clang
 CXX = clang++
 LD   = ld.lld
diff --git a/pwm/oneway.h b/common/oneway.h
similarity index 100%
rename from pwm/oneway.h
rename to common/oneway.h
diff --git a/pwm/Makefile b/pwm/Makefile
index 49f9dd8..823cc5e 100644
--- a/pwm/Makefile
+++ b/pwm/Makefile
@@ -1,8 +1,6 @@
 # ch32v003
 TARGET?= ch32v003
 TOOL  ?= gcc
-#TOOL  ?= clang
-
 
 PRJ    = example
 
@@ -14,7 +12,7 @@ LDLIBS =
 BFLAGS = --strip-unneeded
 
 CFLAGS = -MMD -Wall -ggdb -fno-exceptions -ffunction-sections -fdata-sections
-CFLAGS+= -I. -I./$(TARGET) -I/usr/include/newlib
+CFLAGS+= -I. -I./common -I./$(TARGET) -I/usr/include/newlib
 DEL    = rm -f
 
 # zdrojaky
diff --git a/pwm/common b/pwm/common
new file mode 120000
index 0000000..8332399
--- /dev/null
+++ b/pwm/common
@@ -0,0 +1 @@
+../common/
\ No newline at end of file
diff --git a/pwm/main.cpp b/pwm/main.cpp
index 759463e..66025da 100644
--- a/pwm/main.cpp
+++ b/pwm/main.cpp
@@ -1,3 +1,4 @@
+#include "gpio.h"
 #include "pwmclass.h"
 #include "generator.h"
 //////////////////////////////////////