diff --git a/ports/stm32/mphalport.c b/ports/stm32/mphalport.c
index c5786e740931490c9b3d13c8dc412ec6364a504c..fe7772cf68b3182ebe92d52c2a1c9bc656021a68 100644
--- a/ports/stm32/mphalport.c
+++ b/ports/stm32/mphalport.c
@@ -121,7 +121,7 @@ void mp_hal_gpio_clock_enable(GPIO_TypeDef *gpio) {
     #define AHBxENR_GPIOAEN_Pos RCC_AHB4ENR_GPIOAEN_Pos
     #elif defined(STM32L0)
     #define AHBxENR IOPENR
-    #define AHBxENR_GPIOAEN_Pos RCC_IOPENR_GPIOAEN
+    #define AHBxENR_GPIOAEN_Pos RCC_IOPENR_IOPAEN_Pos
     #elif defined(STM32L4)
     #define AHBxENR AHB2ENR
     #define AHBxENR_GPIOAEN_Pos RCC_AHB2ENR_GPIOAEN_Pos