#error if someone sets both USE_HSI and USE_HSE

ch32v003fun/ch32v003fun.h

@@ -34,6 +34,9 @@
 	#define FUNCONF_DEBUGPRINTF_TIMEOUT 160000
 #endif
 
+#if defined(FUNCONF_USE_HSI) && defined(FUNCONF_USE_HSE) && FUNCONF_USE_HSI && FUNCONF_USE_HSE
+       #error FUNCONF_USE_HSI and FUNCONF_USE_HSE cannot both be set
+#endif
 
 #if !defined( FUNCONF_USE_HSI ) && !defined( FUNCONF_USE_HSE )
 	#define FUNCONF_USE_HSI 1 // Default to use HSI

examples/MCOtest/funconfig.h

@@ -4,5 +4,8 @@
 #define FUNCONF_TINYVECTOR 1
 #define CH32V003           1
 
+#define FUNCONF_USE_HSE 1
+#define FUNCONF_USE_HSI 1
+
 #endif