Interrupt and Overflow check for us_ticker

Author: Ganesh Ramachandran

targets/TARGET_TOSHIBA/TARGET_TMPM066/us_ticker.c

@@ -14,24 +14,24 @@
  * limitations under the License.
  */
 #include "us_ticker_api.h"
+#include "mbed_critical.h"
 
 #define TMR16A_100US                0x960 // fsys = fc = 24MHz, Ttmra = 1/24us, 100us*24us = 2400 = 0x960
 #define TMR16A_SYSCK                ((uint32_t)0x00000001)
 #define TMR16A_RUN                  ((uint32_t)0x00000001)
 #define TMR16A_STOP                 ((uint32_t)0x00000000)
+#define OVERFLOW_32BIT              (0xFFFFFFFF / 0x64)
 
-static uint8_t us_ticker_inited = 0;  // Is ticker initialized yet?
-static volatile uint32_t acc_us_ticker = 0;
-
-// 16Bb high timer counter
-static volatile uint32_t us_ticker_16h = 0;
+static uint8_t us_ticker_inited = 0;                // Is ticker initialized yet?
+static volatile uint32_t ticker_int_counter = 0;    // Amount of overflows until user interrupt
+static volatile uint32_t us_ticker = 0;             // timer counter
 
 void INT16A0_IRQHandler(void)
 {
-    us_ticker_16h++;
-    if (us_ticker_16h >= 0xFFFF) {
-        acc_us_ticker++;
-        us_ticker_16h = 0;
+    us_ticker++;
+
+    if (us_ticker > OVERFLOW_32BIT) {
+        us_ticker = 0;
     }
 }
 
@@ -67,18 +67,30 @@ uint32_t us_ticker_read(void)
     if (!us_ticker_inited) {
         us_ticker_init();
     }
-    ret_val = (((acc_us_ticker << 16) + us_ticker_16h) * 100);
+
+    uint32_t tickerbefore = 0;
+    do {
+        tickerbefore = us_ticker;
+        ret_val = (us_ticker * 100);
+    } while (tickerbefore != us_ticker);
+
     return ret_val;
 }
 
 void us_ticker_set_interrupt(timestamp_t timestamp)
 {
     int delta = 0;
+
     // Stops and clear count operation
     TSB_T16A1->RUN = TMR16A_STOP;
     TSB_T16A1->CR = TMR16A_SYSCK;
     // Set the compare register
     delta = (int)(timestamp - us_ticker_read());
+    if (delta < 0) {
+        // Ticker interrupt handle
+        us_ticker_irq_handler();
+        return;
+    }
     TSB_T16A1->RG = delta;
     // Set Interrupt
     NVIC_EnableIRQ(INT16A1_IRQn);
@@ -98,5 +110,5 @@ void us_ticker_disable_interrupt(void)
 
 void us_ticker_clear_interrupt(void)
 {
-    //no flags to clear
+    NVIC_ClearPendingIRQ(INT16A1_IRQn);
 }