Systick code review and fix of systick timer frequency.

diff --git a/core/systick.c b/core/systick.c
index 82672cb..bcf1ab5 100644 (file)
--- a/core/systick.c
+++ b/core/systick.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- *  drivers/systick.c
+ *  core/systick.c
  *
  * Copyright 2012 Nathael Pajani <nathael.pajani@ed3l.fr>
  *
@@ -120,6 +120,7 @@ uint32_t systick_get_timer_val(void)
        return systick->value;
 }
 /* Get the "timer wrapped" indicator.
+ * Used in usleep() function.
  * Note : the first to call this function will get the right information.
  * All subsequent calls will get wrong indication.
  * Thus this function is not exported to user space, user should compare global
@@ -153,16 +154,19 @@ void systick_timer_on(uint32_t ms)
                reload = (get_main_clock() / 1000) - 1;
                ms = 1;
        }
-       systick->reload_val = reload;
+       /* For the LPC1224 the system tick clock is fixed to half the frequency of the system clock */
+       reload = reload >> 1; /* Divide by 2 */
+       systick->reload_val = (reload & 0xffffff);
        tick_ms = ms;
 
        /* Start counting from the reload value, writting anything would do ... */
-       systick->value = 0;
+       systick->value = reload;
 
        /* And enable counter interrupt */
-       systick->control = (LPC_SYSTICK_CTRL_TICKINT | LPC_SYSTICK_CTRL_CLKSOURCE);
+       systick->control = LPC_SYSTICK_CTRL_TICKINT;
        systick_running = 0;
 
+       /* FIXME : document this */
        NVIC_SetPriority(SYSTICK_IRQ, ((1 << LPC_NVIC_PRIO_BITS) - 1));
 }
 

diff --git a/include/core/system.h b/include/core/system.h
index 9f791db..9ebc2ee 100644 (file)
--- a/include/core/system.h
+++ b/include/core/system.h
@@ -160,7 +160,7 @@ uint32_t get_sleep(void);
 uint32_t sleep(void);
 
 void msleep(uint32_t ms);
-void usleep(uint32_t ms);
+void usleep(uint32_t us);
 
 
 #endif /* CORE_SYSTEM_H */