diff --git a/Source/portable/IAR/78K0R/portmacro.h b/Source/portable/IAR/78K0R/portmacro.h
index 1255ff6d5..1bd48ef31 100644
--- a/Source/portable/IAR/78K0R/portmacro.h
+++ b/Source/portable/IAR/78K0R/portmacro.h
@@ -72,7 +72,7 @@ extern "C" {
 #define portLONG        long
 #define portSHORT       short
 #define portSTACK_TYPE  unsigned short
-#define portBASE_TYPE   int
+#define portBASE_TYPE   short
 
 #if (configUSE_16_BIT_TICKS==1)
 	typedef unsigned int portTickType;