2 files changed, 8 insertions, 6 deletions
diff --git a/libmaple/systick.c b/libmaple/systick.c
index 12a3e22..2b09a64 100644
--- a/libmaple/systick.c
+++ b/libmaple/systick.c
@@ -39,7 +39,7 @@
 #define SYSTICK_TICKINT         BIT(1)    // Interrupt on systick countdown
 #define SYSTICK_ENABLE          BIT(0)    // Turn on the counter
 
-volatile uint32 systick_timer_millis = 0;
+volatile uint32 systick_timer_millis;
 
 void systick_init(uint32 reload_val) {
     /* Set the reload counter to tick every 1ms  */
@@ -65,8 +65,7 @@ void systick_resume() {
             SYSTICK_TICKINT);
 }
 
+/** SysTick interrupt handler.  Bumps up the tick counter. */
 void SysTickHandler(void) {
     systick_timer_millis++;
 }
-
-
diff --git a/libmaple/systick.h b/libmaple/systick.h
index 7ec8497..ae1268a 100644
--- a/libmaple/systick.h
+++ b/libmaple/systick.h
@@ -33,14 +33,17 @@
 
 #include "libmaple.h"
 
+#ifdef __cplusplus
+extern "C"{
+#endif
+
 #define SYSTICK_CSR             0xE000E010  // Control and status register
 #define SYSTICK_CNT             0xE000E018  // Current value register
 
 #define SYSTICK_CSR_COUNTFLAG   BIT(16)
 
-#ifdef __cplusplus
-extern "C"{
-#endif
+/** System elapsed time in milliseconds */
+volatile uint32 systick_timer_millis;
 
 void systick_init(uint32 reload_val);
 void systick_disable();