diff --git a/drivers/avr/system.h b/drivers/avr/system.h
index aa5eb50..f2e2e92 100644
--- a/drivers/avr/system.h
+++ b/drivers/avr/system.h
@@ -24,29 +24,30 @@ typedef uint8_t bool;
 #define F_CPU 8000000
 
 
-/* LED matrix columns.  */
-#define LEDMAT_COL1_PIO PIO_DEFINE(PORT_C, 6)
-#define LEDMAT_COL2_PIO PIO_DEFINE(PORT_B, 7)
-#define LEDMAT_COL3_PIO PIO_DEFINE(PORT_C, 4)
-#define LEDMAT_COL4_PIO PIO_DEFINE(PORT_C, 7)
-#define LEDMAT_COL5_PIO PIO_DEFINE(PORT_C, 5)
+/* LED matrix columns.  (Note these are labelled in reverse order on
+   the schematic.)  */
+#define LEDMAT_COL1_PIO PC6_PIO
+#define LEDMAT_COL2_PIO PB7_PIO
+#define LEDMAT_COL3_PIO PC4_PIO
+#define LEDMAT_COL4_PIO PC7_PIO
+#define LEDMAT_COL5_PIO PC5_PIO
 #define LEDMAT_COLS_NUM 5
 
 
 /* LED matrix rows.  */
-#define LEDMAT_ROW1_PIO PIO_DEFINE(PORT_B, 6)
-#define LEDMAT_ROW2_PIO PIO_DEFINE(PORT_B, 5)
-#define LEDMAT_ROW3_PIO PIO_DEFINE(PORT_B, 4)
-#define LEDMAT_ROW4_PIO PIO_DEFINE(PORT_B, 3)
-#define LEDMAT_ROW5_PIO PIO_DEFINE(PORT_B, 2)
-#define LEDMAT_ROW6_PIO PIO_DEFINE(PORT_B, 1)
-#define LEDMAT_ROW7_PIO PIO_DEFINE(PORT_B, 0)
+#define LEDMAT_ROW1_PIO PB6_PIO
+#define LEDMAT_ROW2_PIO PB5_PIO
+#define LEDMAT_ROW3_PIO PB4_PIO 
+#define LEDMAT_ROW4_PIO PB3_PIO 
+#define LEDMAT_ROW5_PIO PB2_PIO 
+#define LEDMAT_ROW6_PIO PB1_PIO 
+#define LEDMAT_ROW7_PIO PB0_PIO 
 #define LEDMAT_ROWS_NUM 7
 
 
 /* Button.  */
 #define BUTTON1 0
-#define BUTTON1_PIO PIO_DEFINE(PORT_D, 7)
+#define BUTTON1_PIO PD7_PIO
 
 
 /* Navswitch.  */
@@ -60,13 +61,13 @@ typedef uint8_t bool;
 
 /* LED (active high).  */
 #define LED1 0
-#define LED1_PIO PIO_DEFINE(PORT_C, 2)
+#define LED1_PIO PC2_PIO
 
 
 /* Infrared transmitter LED and receiver.  */
-#define IR_TX_LOW_PIO PIO_DEFINE(PORT_D, 3)
-#define IR_TX_HIGH_PIO PIO_DEFINE(PORT_D, 0)
-#define IR_RX_PIO PIO_DEFINE(PORT_D, 2)
+#define IR_TX_LOW_PIO PD3_PIO 
+#define IR_TX_HIGH_PIO PD0_PIO
+#define IR_RX_PIO PD2_PIO
 
 #define IR_MODULATION_FREQ 36e3