diff --git a/flight/sys/pios.c b/flight/sys/pios.c
index 4ccf51087..3ad952918 100644
--- a/flight/sys/pios.c
+++ b/flight/sys/pios.c
@@ -37,7 +37,7 @@
 #include <queue.h>
 
 
-/* FreeRTOS Tasks */
+/* FreeRTOS Prototypes */
 void PiosMainTask( void *pvParameters );
 void SensorTask( void *pvParameters );
 
diff --git a/flight/sys/pios_irq.c b/flight/sys/pios_irq.c
index 0e14da013..b2fb68fbe 100644
--- a/flight/sys/pios_irq.c
+++ b/flight/sys/pios_irq.c
@@ -25,9 +25,19 @@
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
+
 /* Project Includes */
 #include "pios.h"
 
+
+/* Public Function Prototypes */
+int IRQDisable(void);
+int IRQEnable(void);
+
+
+/* Private Function Prototypes */
+
+
 /* Local Variables */
 /* The nesting counter ensures, that interrupts won't be enabled so long nested functions disable them */
 static unsigned int nested_ctr;
@@ -35,7 +45,14 @@ static unsigned int nested_ctr;
 /* Stored priority level before IRQ has been disabled (important for co-existence with vPortEnterCritical) */
 static unsigned int prev_primask;
 
-/* Disables all interrupts (nested) */
+
+/*******************************************************************************
+* Function Name  : IRQDisable
+* Description    : Disables all interrupts (nested)
+* Input          : None
+* Output         : None
+* Return         : Zero on no error
+*******************************************************************************/
 int IRQDisable(void)
 {
 	/* Get current priority if nested level == 0 */
@@ -59,7 +76,14 @@ int IRQDisable(void)
 	return 0;
 }
 
-/* Enables all interrupts (nested) */
+
+/*******************************************************************************
+* Function Name  : IRQEnable
+* Description    : Enables all interrupts (nested)
+* Input          : None
+* Output         : None
+* Return         : Zero on no error, -1 on nesting error
+*******************************************************************************/
 int IRQEnable(void)
 {
 	/* Check for nesting error */
@@ -81,4 +105,4 @@ int IRQEnable(void)
 
 	/* No error */
 	return 0;
-}
\ No newline at end of file
+}
diff --git a/flight/sys/pios_led.c b/flight/sys/pios_led.c
index e7125391e..22c4434a5 100644
--- a/flight/sys/pios_led.c
+++ b/flight/sys/pios_led.c
@@ -25,13 +25,34 @@
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
+
+/* Project Includes */
 #include "pios.h"
 
+
+/* Public Function Prototypes */
+void LED_INIT(void);
+void LED_ON(LedTypeDef LEDNum);
+void LED_OFF(LedTypeDef LEDNum);
+void LED_TOGGLE(LedTypeDef LEDNum);
+
+
+/* Private Function Prototypes */
+
+
+/* Local Variables */
 GPIO_TypeDef* LED_GPIO_PORT[NUM_LED] = {LED1_GPIO_PORT, LED2_GPIO_PORT};
 const uint16_t LED_GPIO_PIN[NUM_LED] = {LED1_GPIO_PIN, LED2_GPIO_PIN};
 const uint32_t LED_GPIO_CLK[NUM_LED] = {LED1_GPIO_CLK, LED2_GPIO_CLK};
 
-/* Initialises all the LED's */
+
+/*******************************************************************************
+* Function Name  : LED_INIT
+* Description    : Initialises all the LED's
+* Input          : None
+* Output         : None
+* Return         : None
+*******************************************************************************/
 void LED_INIT(void)
 {
 	GPIO_InitTypeDef GPIO_InitStructure;
@@ -45,16 +66,40 @@ void LED_INIT(void)
 	}
 }
 
+
+/*******************************************************************************
+* Function Name  : LED_ON
+* Description    : Turn on LED
+* Input          : LED Number
+* Output         : None
+* Return         : None
+*******************************************************************************/
 void LED_ON(LedTypeDef LEDNum)
 {
 	LED_GPIO_PORT[LEDNum]->BSRR = LED_GPIO_PIN[LEDNum];
 }
 
+
+/*******************************************************************************
+* Function Name  : LED_OFF
+* Description    : Turn off LED
+* Input          : LED Number
+* Output         : None
+* Return         : None
+*******************************************************************************/
 void LED_OFF(LedTypeDef LEDNum)
 {
 	LED_GPIO_PORT[LEDNum]->BRR = LED_GPIO_PIN[LEDNum];
 }
 
+
+/*******************************************************************************
+* Function Name  : LED_TOGGLE
+* Description    : Turn on/off LED
+* Input          : LED Number
+* Output         : None
+* Return         : None
+*******************************************************************************/
 void LED_TOGGLE(LedTypeDef LEDNum)
 {
 	LED_GPIO_PORT[LEDNum]->ODR ^= LED_GPIO_PIN[LEDNum];