micros() implementation without irq disable

diff --git a/teensy3/pins_teensy.c b/teensy3/pins_teensy.c
index 1c81ee9..52df777 100644 (file)
--- a/teensy3/pins_teensy.c
+++ b/teensy3/pins_teensy.c
@@ -690,7 +690,7 @@ volatile uint32_t systick_millis_count = 0;
 
 //uint32_t systick_current, systick_count, systick_istatus;  // testing only
 
-uint32_t micros(void)
+static uint32_t micros_mask(void)
 {
        uint32_t count, current, istatus;
 
@@ -707,6 +707,24 @@ uint32_t micros(void)
        return count * 1000 + current / (F_CPU / 1000000);
 }
 
+uint32_t micros(void)
+{
+       uint32_t count, current, istatus;
+
+       if (nvic_execution_priority() <= (SCB_SHPR3 >> 24))
+               return micros_mask();
+
+       do {
+               current = SYST_CVR;
+               count = systick_millis_count;
+               istatus = SCB_ICSR;     // bit 26 indicates if systick exception pending
+       }
+       while (istatus & SCB_ICSR_PENDSTSET);
+
+       current = ((F_CPU / 1000) - 1) - current;
+       return count * 1000 + current / (F_CPU / 1000000);
+}
+
 void delay(uint32_t ms)
 {
        uint32_t start = micros();