clock: [#55] Overflow handling for FreeRTOS stats.

source/shoh/freertos/FreeRTOSConfig.h

@@ -126,9 +126,10 @@ to exclude the API function. */
  * must set up LPC_SCT1.
  */
 void vConfigureTimerForRunTimeStats(void);
+unsigned long ulGetTimeForRunTimeStats(void);
 #define portCONFIGURE_TIMER_FOR_RUN_TIME_STATS() vConfigureTimerForRunTimeStats()
 /* The value is read directly from the counter register for efficiency and low overhead. */
-#define portGET_RUN_TIME_COUNTER_VALUE() LPC_SCT1->COUNT_U
+#define portGET_RUN_TIME_COUNTER_VALUE() ulGetTimeForRunTimeStats()
 
 /* Cortex-M specific definitions. */
 #ifdef __NVIC_PRIO_BITS

source/shoh/src/peripherals/Clock.cpp

@@ -29,7 +29,7 @@ extern "C" {
 
   /** 
    * @brief This function is used by FreeRTOS to configure the collection of
-   * time used by tasks.
+   * time used by tasks. (This timer is also used for logging timestamps.)
    */
   void
   vConfigureTimerForRunTimeStats (void)
@@ -55,6 +55,20 @@ extern "C" {
     LPC_SCT1->CONFIG = SCT_CONFIG_32BIT_COUNTER;
     LPC_SCT1->CTRL_U = SCT_CTRL_CLRCTR_L;
   }
+
+  /**
+   * @brief Used by FreeRTOS to collect runtime statistics.
+   * @paragraph FreeRTOS is unable to handle the counter overflow, so it must be done from our side.
+   * This solution will break eventually later on, presumably after 1193 hours of runtime,
+   * since unsigned long won't be able to hold more than that amount of milliseconds.
+   * FreeRTOS expects to get unsigned long, so there's nothing more that can be done.
+   * @return unsigned long 
+   */
+  unsigned long ulGetTimeForRunTimeStats(void)
+  {
+    return (unsigned long)(((double)(counter_overflows - 1) * max_counter_value) + LPC_SCT1->COUNT_U)
+            / ((double)Chip_Clock_GetMainClockRate() / 1000);
+  }
 }
 
 /**