diff --git a/examples/spi_oled/spi_oled.c b/examples/spi_oled/spi_oled.c
index 7359bb21978c046f0e8b69c70e0be017c461e579..f5231e8833bc00c821be9c87fb8749363ed3125e 100644
--- a/examples/spi_oled/spi_oled.c
+++ b/examples/spi_oled/spi_oled.c
@@ -7,6 +7,11 @@
 #define SYSTEM_CORE_CLOCK 48000000
 #define APB_CLOCK SYSTEM_CORE_CLOCK
 
+// what type of OLED - uncomment just one
+//#define SSD1306_64X32
+//#define SSD1306_128X32
+#define SSD1306_128X64
+
 #include "ch32v003fun.h"
 #include <stdio.h>
 #include "ssd1306_spi.h"
diff --git a/examples/spi_oled/ssd1306.h b/examples/spi_oled/ssd1306.h
index 74aec8d4e66535439292080acc42b3e72c0933a1..19ea88db1053ad211038656b1dbe1452f8f6e2bb 100644
--- a/examples/spi_oled/ssd1306.h
+++ b/examples/spi_oled/ssd1306.h
@@ -13,12 +13,11 @@
 // comfortable packet size for this OLED
 #define SSD1306_PSZ 32
 
-// what type of OLED - uncomment just one
-//#define SSD1306_64X32
-//#define SSD1306_128X32
-#define SSD1306_128X64
-
 // characteristics of each type
+#if !defined (SSD1306_64X32) && !defined (SSD1306_128X32) && !defined (SSD1306_128X64)
+	#error "Please define the SSD1306_WXH resolution used in your application"
+#endif
+
 #ifdef SSD1306_64X32
 #define SSD1306_W 64
 #define SSD1306_H 32