diff --git a/include/libopencm3/lpc17xx/memorymap.h b/include/libopencm3/lpc17xx/memorymap.h
index b8c09080..f68f5904 100644
--- a/include/libopencm3/lpc17xx/memorymap.h
+++ b/include/libopencm3/lpc17xx/memorymap.h
@@ -26,12 +26,20 @@
 /* --- LPC17XX specific peripheral definitions ----------------------------- */
 
 /* Memory map for all busses */
+#define PERIPH_BASE_GPIO		(0x2009C000U)
 #define PERIPH_BASE_APB0		(0x40000000U)
 #define PERIPH_BASE_APB1		(0x40080000U)
 #define PERIPH_BASE_AHB			(0x50000000U)
 
 /* Register boundary addresses */
 
+/* GPIO */
+#define GPIO_PIO0_BASE			(PERIPH_BASE_GPIO + 0x00)
+#define GPIO_PIO1_BASE			(PERIPH_BASE_GPIO + 0x20)
+#define GPIO_PIO2_BASE			(PERIPH_BASE_GPIO + 0x40)
+#define GPIO_PIO3_BASE			(PERIPH_BASE_GPIO + 0x60)
+#define GPIO_PIO4_BASE			(PERIPH_BASE_GPIO + 0x80)
+
 /* APB0 */
 #define WDT_BASE			(PERIPH_BASE_APB0 + 0x00000)
 #define TIMER0_BASE			(PERIPH_BASE_APB0 + 0x04000)