Diff: targets/hal/TARGET_STM/TARGET_NUCLEO_F030R8/us_ticker.c

Revision:

91:0a39e62a0464

Parent:

87:085cde657901

Child:

92:05f19f05c134

--- a/targets/hal/TARGET_STM/TARGET_NUCLEO_F030R8/us_ticker.c	Tue Feb 11 23:15:06 2014 +0000
+++ b/targets/hal/TARGET_STM/TARGET_NUCLEO_F030R8/us_ticker.c	Thu Feb 13 18:15:05 2014 +0000
@@ -37,8 +37,15 @@
 
 static int      us_ticker_inited = 0;
 static uint32_t SlaveCounter = 0;
-static uint32_t us_ticker_int_counter = 0;
-static uint16_t us_ticker_int_remainder = 0;
+static uint32_t oc_int_part = 0;
+static uint16_t oc_rem_part = 0;
+
+void set_compare(uint16_t count) {
+    // Set new output compare value
+    TIM_SetCompare1(TIM_MST, count);
+    // Enable IT
+    TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE);
+}
 
 // Used to increment the slave counter
 static void tim_update_irq_handler(void) {
@@ -50,27 +57,30 @@
 
 // Used by interrupt system
 static void tim_oc_irq_handler(void) {
+    uint16_t cval = TIM_MST->CNT;
+  
     // Clear interrupt flag
     if (TIM_GetITStatus(TIM_MST, TIM_IT_CC1) == SET) {
         TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1);
     }
-    
-    if (us_ticker_int_counter > 0) {
-        TIM_SetCompare1(TIM_MST, 0xFFFF);
-        us_ticker_int_counter--;
-    } else {
-        if (us_ticker_int_remainder > 0) {
-            TIM_SetCompare1(TIM_MST, us_ticker_int_remainder);
-            us_ticker_int_remainder = 0;
-        } else {
-            // This function is going to disable the interrupts if there are
-            // no other events in the queue
+
+    if (oc_rem_part > 0) {
+        set_compare(oc_rem_part); // Finish the remaining time left
+        oc_rem_part = 0;
+    }
+    else {
+        if (oc_int_part > 0) {
+            set_compare(0xFFFF);
+            oc_rem_part = cval; // To finish the counter loop the next time
+            oc_int_part--;
+        }
+        else {
             us_ticker_irq_handler();
         }
-    }    
+    }
 }
 
-void us_ticker_init(void) {    
+void us_ticker_init(void) {
     TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
   
     if (us_ticker_inited) return;
@@ -89,13 +99,12 @@
     
     // Configure interrupts
     TIM_ITConfig(TIM_MST, TIM_IT_Update, ENABLE);
-    TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE);
     
-    // For 32-bit counter
+    // Update interrupt used for 32-bit counter
     NVIC_SetVector(TIM_MST_UP_IRQ, (uint32_t)tim_update_irq_handler);
     NVIC_EnableIRQ(TIM_MST_UP_IRQ);
     
-    // For ouput compare
+    // Output compare interrupt used for timeout feature
     NVIC_SetVector(TIM_MST_OC_IRQ, (uint32_t)tim_oc_irq_handler);
     NVIC_EnableIRQ(TIM_MST_OC_IRQ);
   
@@ -112,10 +121,10 @@
     // value in the past. Avoid this by computing consecutive values of the timer until they
     // are properly ordered.
     counter = (uint32_t)(SlaveCounter << 16);
-    counter += (uint32_t)TIM_GetCounter(TIM_MST);
+    counter += TIM_MST->CNT;
     while (1) {
         counter2 = (uint32_t)(SlaveCounter << 16);
-        counter2 += (uint32_t)TIM_GetCounter(TIM_MST);
+        counter2 += TIM_MST->CNT;
         if (counter2 > counter) {
             break;
         }
@@ -126,22 +135,21 @@
 
 void us_ticker_set_interrupt(unsigned int timestamp) {
     int delta = (int)(timestamp - us_ticker_read());
+    uint16_t cval = TIM_MST->CNT;
 
     if (delta <= 0) { // This event was in the past
         us_ticker_irq_handler();
-        return;
     }
     else {
-        us_ticker_int_counter   = (uint32_t)(delta >> 16);
-        us_ticker_int_remainder = (uint16_t)(delta & 0xFFFF);
-        if (us_ticker_int_counter > 0) { // means delta > 0xFFFF
-            TIM_SetCompare1(TIM_MST, 0xFFFF);
-            us_ticker_int_counter--;
+        oc_int_part = (uint32_t)(delta >> 16);
+        oc_rem_part = (uint16_t)(delta & 0xFFFF);
+        if (oc_rem_part <= (0xFFFF - cval)) {
+            set_compare(cval + oc_rem_part);
+            oc_rem_part = 0;
         } else {
-            TIM_SetCompare1(TIM_MST, us_ticker_int_remainder);
-            us_ticker_int_remainder = 0;
+            set_compare(0xFFFF);
+            oc_rem_part = oc_rem_part - (0xFFFF - cval);
         }
-        TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE);
     }
 }