diff --git a/include/libopencm3/stm32/common/syscfg_common_l1f234.h b/include/libopencm3/stm32/common/syscfg_common_l1f234.h
index 776e12da..5e7f2d42 100644
--- a/include/libopencm3/stm32/common/syscfg_common_l1f234.h
+++ b/include/libopencm3/stm32/common/syscfg_common_l1f234.h
@@ -50,6 +50,10 @@ specific memorymap.h header before including this header file.*/
 
 #define SYSCFG_CMPCR			MMIO32(SYSCFG_BASE + 0x20)
 
+/* --- SYSCFG_EXTICR Values -------------------------------------------------*/
+
+#define SYSCFG_EXTICR_FIELDSIZE		4
+
 #endif
 /**@}*/
 
diff --git a/include/libopencm3/stm32/f0/syscfg.h b/include/libopencm3/stm32/f0/syscfg.h
index 7e796a05..fcfb74ab 100644
--- a/include/libopencm3/stm32/f0/syscfg.h
+++ b/include/libopencm3/stm32/f0/syscfg.h
@@ -91,7 +91,7 @@
 
 /* SYSCFG_EXTICR Values -- --------------------------------------------------*/
 
-#define SYSCFG_EXTICR_SKIP		4
+#define SYSCFG_EXTICR_FIELDSIZE		4
 #define SYSCFG_EXTICR_GPIOA		0
 #define SYSCFG_EXTICR_GPIOB		1
 #define SYSCFG_EXTICR_GPIOC		2
diff --git a/include/libopencm3/stm32/f1/gpio.h b/include/libopencm3/stm32/f1/gpio.h
index 2de19ce9..e8b42506 100644
--- a/include/libopencm3/stm32/f1/gpio.h
+++ b/include/libopencm3/stm32/f1/gpio.h
@@ -933,10 +933,10 @@ Line Devices only
 
 /**@}*/
 
-/* --- AFIO_EXTICR1 values ------------------------------------------------- */
-/* --- AFIO_EXTICR2 values ------------------------------------------------- */
-/* --- AFIO_EXTICR3 values ------------------------------------------------- */
-/* --- AFIO_EXTICR4 values ------------------------------------------------- */
+/* --- AFIO_EXTICRx values ------------------------------------------------- */
+
+/** EXTICR port selection bits  */
+#define AFIO_EXTICR_FIELDSIZE			4
 
 /** @defgroup afio_exti Alternate Function EXTI pin number
 @ingroup gpio_defines
diff --git a/include/libopencm3/stm32/l0/syscfg.h b/include/libopencm3/stm32/l0/syscfg.h
index 1ae0a947..767ddf44 100644
--- a/include/libopencm3/stm32/l0/syscfg.h
+++ b/include/libopencm3/stm32/l0/syscfg.h
@@ -111,6 +111,7 @@
 
 /* SYSCFG_EXTICR Values -- --------------------------------------------------*/
 
+#define SYSCFG_EXTICR_FIELDSIZE		4
 #define SYSCFG_EXTICR_GPIOA		0
 #define SYSCFG_EXTICR_GPIOB		1
 #define SYSCFG_EXTICR_GPIOC		2
diff --git a/include/libopencm3/stm32/l4/syscfg.h b/include/libopencm3/stm32/l4/syscfg.h
index 934d7ac5..d11510b6 100644
--- a/include/libopencm3/stm32/l4/syscfg.h
+++ b/include/libopencm3/stm32/l4/syscfg.h
@@ -81,6 +81,7 @@
 
 /* --- SYSCFG_EXTICR Values -------------------------------------------------*/
 
+#define SYSCFG_EXTICR_FIELDSIZE		4
 #define SYSCFG_EXTICR_GPIOA		0
 #define SYSCFG_EXTICR_GPIOB		1
 #define SYSCFG_EXTICR_GPIOC		2