From: notaz <notasas@gmail.com>
Date: Sat, 25 Oct 2014 22:14:39 +0000 (+0300)
Subject: micros() implementation without irq disable
X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=328c1b3394b711135fed11225cccef84220ef6be;p=teensytas.git

micros() implementation without irq disable
---

diff --git a/teensy3/pins_teensy.c b/teensy3/pins_teensy.c
index 1c81ee9..52df777 100644
--- 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();