diff --git a/include/hw/gpio/nrf51_gpio.h b/include/hw/gpio/nrf51_gpio.h
index 337ee534bb..1d62bbc928 100644
--- a/include/hw/gpio/nrf51_gpio.h
+++ b/include/hw/gpio/nrf51_gpio.h
@@ -42,7 +42,7 @@
 #define NRF51_GPIO_REG_DIRSET       0x518
 #define NRF51_GPIO_REG_DIRCLR       0x51C
 #define NRF51_GPIO_REG_CNF_START    0x700
-#define NRF51_GPIO_REG_CNF_END      0x77F
+#define NRF51_GPIO_REG_CNF_END      0x77C
 
 #define NRF51_GPIO_PULLDOWN 1
 #define NRF51_GPIO_PULLUP 3