Merge pull request #909 from OlegHahm/msp430_hwtimer

msp430: hwtimer: handle overflow correctly

cpu/cc430/hwtimer_cc430.c

@@ -20,11 +20,9 @@
  *
  */
 
-#include <legacymsp430.h>
-#include "board.h"
+#include "cpu.h"
 #include "hwtimer.h"
 #include "hwtimer_arch.h"
-#include "cpu.h"
 
 #define ENABLE_DEBUG (0)
 #include "debug.h"
@@ -33,15 +31,18 @@ static uint32_t ticks = 0;
 
 extern void (*int_handler)(int);
 extern void timer_unset(short timer);
+extern uint16_t overflow_interrupt[HWTIMER:_MAXTIMERS+1];
+extern uint16_t timer_round;
 
 void timerA_init(void)
 {
-    ticks = 0;                               // Set tick counter value to 0
-    TA0CTL = TASSEL_1 + TACLR;               // Clear the timer counter, set ACLK
-    TA0CTL &= ~TAIE;                         // Clear the IFG
-
     volatile unsigned int *ccr = &TA0CCR0;
     volatile unsigned int *ctl = &TA0CCTL0;
+    ticks = 0;                               /* Set tick counter value to 0 */
+    timer_round = 0;                         /* Set to round 0 */
+    TA0CTL = TASSEL_1 + TACLR;               /* Clear the timer counter, set ACLK */
+    TA0CTL &= ~TAIFG;                        /* Clear the IFG */
+    TA0CTL |= TAIE;                          /* Enable TAIE (overflow IRQ) */
 
     for (int i = 0; i < HWTIMER_MAXTIMERS; i++) {
         *(ccr + i) = 0;
@@ -55,9 +56,10 @@ void timerA_init(void)
 interrupt(TIMER0_A0_VECTOR) __attribute__((naked)) timer0_a0_isr(void)
 {
     __enter_isr();
-
-    timer_unset(0);
-    int_handler(0);
+    if (overflow_interrupt[0] == timer_round) {
+        timer_unset(0);
+        int_handler(0);
+    }
     __exit_isr();
 }
 
@@ -66,13 +68,15 @@ interrupt(TIMER0_A1_VECTOR) __attribute__((naked)) timer0_a1_5_isr(void)
     __enter_isr();
 
     short taiv = TA0IV;
-    short timer;
-
-    if (taiv & TAIFG) {
+    short timer = taiv / 2;
+    /* TAIV = 0x0E means overflow */
+    if (taiv == 0x0E) {
         DEBUG("Overflow\n");
+        timer_round += 1;
     }
-    else {
-        timer = (taiv / 2);
+    /* check which CCR has been hit and if the overflow counter for this timer
+     * has been reached */
+    else if (overflow_interrupt[timer] == timer_round) {
         timer_unset(timer);
         int_handler(timer);
     }

cpu/msp430-common/hwtimer_cpu.c

@@ -60,7 +60,7 @@ static void timer_set_nostart(unsigned long value, short timer)
 
 static void timer_set(unsigned long value, short timer)
 {
-    DEBUG("Setting timer %u to %lu\n", timer, value);
+    DEBUG("Setting timer %u to %u overflows and %lu\n", timer, overflow_interrupt[timer], value);
     timer_set_nostart(value, timer);
     timer_enable_interrupt(timer);
 }
@@ -82,7 +82,6 @@ void hwtimer_arch_init(void (*handler)(int), uint32_t fcpu)
     (void) fcpu;
     timerA_init();
     int_handler = handler;
-    timer_enable_interrupt(0);
 }
 
 void hwtimer_arch_enable_interrupt(void)
@@ -107,9 +106,9 @@ void hwtimer_arch_set(unsigned long offset, short timer)
 
 void hwtimer_arch_set_absolute(unsigned long value, short timer)
 {
-    uint16_t small_value = value % 0xFFFF;
+    uint16_t small_value = value & 0xFFFF;
     overflow_interrupt[timer] = (uint16_t)(value >> 16);
-    timer_set(small_value,timer);
+    timer_set(small_value, timer);
 }
 
 void hwtimer_arch_unset(short timer)

cpu/msp430x16x/hwtimer_msp430.c

@@ -24,6 +24,9 @@
 #include "hwtimer.h"
 #include "hwtimer_arch.h"
 
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
 static uint32_t ticks = 0;
 
 extern void (*int_handler)(int);
@@ -35,11 +38,11 @@ void timerA_init(void)
 {
     volatile unsigned int *ccr;
     volatile unsigned int *ctl;
-    ticks = 0;                               // Set tick counter value to 0
-    timer_round = 0;                         // Set to round 0
-    TACTL = TASSEL_1 + TACLR;                // Clear the timer counter, set ACLK
-    TACTL &= ~TAIFG;                         // Clear the IFG
-    TACTL &= ~TAIE;                          // Clear the IFG
+    ticks = 0;                               /* Set tick counter value to 0 */
+    timer_round = 0;                         /* Set to round 0 */
+    TACTL = TASSEL_1 + TACLR;                /* Clear the timer counter, set ACLK */
+    TACTL &= ~TAIFG;                         /* Clear the IFG */
+    TACTL |= TAIE;                           /* Enable TAIE (overflow IRQ) */
 
     for (int i = 0; i < HWTIMER_MAXTIMERS; i++) {
         ccr = &TACCR0 + (i);
@@ -55,7 +58,10 @@ void timerA_init(void)
 interrupt(TIMERA0_VECTOR) __attribute__((naked)) timer_isr_ccr0(void)
 {
     __enter_isr();
-    timer_round += 1;
+    if (overflow_interrupt[0] == timer_round) {
+        timer_unset(0);
+        int_handler(0);
+    }
     __exit_isr();
 }
 
@@ -64,12 +70,17 @@ interrupt(TIMERA1_VECTOR) __attribute__((naked)) timer_isr(void)
     __enter_isr();
 
     short taiv = TAIV;
-    if (!(taiv & TAIV_TAIFG)) {
-        short timer = taiv / 2;
-        if (overflow_interrupt[timer] == timer_round) {
-            timer_unset(timer);
-            int_handler(timer);
-        }
+    short timer = taiv / 2;
+    /* TAIV = 0x0A means overflow */
+    if (taiv == 0x0A) {
+        DEBUG("Overflow\n");
+        timer_round += 1;
+    }
+    /* check which CCR has been hit and if the overflow counter for this timer
+     * has been reached */
+    else if (overflow_interrupt[timer] == timer_round) {
+        timer_unset(timer);
+        int_handler(timer);
     }
 
     __exit_isr();

tests/test_hwtimer/main.c

@@ -36,11 +36,6 @@ int main(void)
 {
     puts("hwtimer test application...");
 
-    puts("Initializing hwtimer...");
-    hwtimer_init();
-
-    puts("Initializing hwtimer [OK].");
-
     puts("");
     puts("  Timers should print \"callback x\" once when they run out.");
     printf("  The order for x is 1, n-1, n-2, ..., 2 where n is the number of available hardware timers (%u on this platform).\n", HWTIMER_MAXTIMERS);