From 92f4066a72056901105308ce2e133cc4048b51c2 Mon Sep 17 00:00:00 2001
From: Edgar Bonet <linux@edgar-bonet.org>
Date: Wed, 19 Sep 2018 12:31:52 +0200
Subject: [PATCH 1/2] Fix micros() rollover issue in FFT_03.ino

---
 Examples/FFT_03/FFT_03.ino | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Examples/FFT_03/FFT_03.ino b/Examples/FFT_03/FFT_03.ino
index 868c8be..30d5a7a 100644
--- a/Examples/FFT_03/FFT_03.ino
+++ b/Examples/FFT_03/FFT_03.ino
@@ -59,7 +59,7 @@ void loop()
 
       vReal[i] = analogRead(CHANNEL);
       vImag[i] = 0;
-      while(micros() < (microseconds + sampling_period_us)){
+      while(micros() - microseconds < sampling_period_us){
         //empty loop
       }
   }

From c564008306528a702f6f8b921de66a7d4da4d922 Mon Sep 17 00:00:00 2001
From: Edgar Bonet <linux@edgar-bonet.org>
Date: Wed, 19 Sep 2018 12:32:05 +0200
Subject: [PATCH 2/2] Ensure accurate sampling frequency in FFT_03.ino

---
 Examples/FFT_03/FFT_03.ino | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Examples/FFT_03/FFT_03.ino b/Examples/FFT_03/FFT_03.ino
index 30d5a7a..9e1640c 100644
--- a/Examples/FFT_03/FFT_03.ino
+++ b/Examples/FFT_03/FFT_03.ino
@@ -53,15 +53,15 @@ void setup()
 void loop()
 {
   /*SAMPLING*/
+  microseconds = micros();
   for(int i=0; i<samples; i++)
   {
-      microseconds = micros();    //Overflows after around 70 minutes!
-
       vReal[i] = analogRead(CHANNEL);
       vImag[i] = 0;
       while(micros() - microseconds < sampling_period_us){
         //empty loop
       }
+      microseconds += sampling_period_us;
   }
   /* Print the results of the sampling according to time */
   Serial.println("Data:");