diff --git a/cpu/sam3/periph/gpio.c b/cpu/sam3/periph/gpio.c
index d22329e1cd..ef5dab67e8 100644
--- a/cpu/sam3/periph/gpio.c
+++ b/cpu/sam3/periph/gpio.c
@@ -45,10 +45,7 @@
 /**
  * @brief Allocation of memory for 7 independent interrupt slots
  */
-static gpio_isr_ctx_t exti_ctx[CTX_NUMOF] = {
-    {NULL, NULL}, {NULL, NULL}, {NULL, NULL}, {NULL, NULL},
-    {NULL, NULL}, {NULL, NULL}, {NULL, NULL}
-};
+static gpio_isr_ctx_t exti_ctx[CTX_NUMOF] = {{0}};
 
 /**
  * @brief Allocation of 4 bit per pin to map a pin to an interrupt context