From f03093332bd910a05af31838d06fa7f1c1e5040c Mon Sep 17 00:00:00 2001
From: Cristian Maglie <c.maglie@bug.st>
Date: Thu, 26 Sep 2013 01:16:27 +0200
Subject: [PATCH] [sam] Fixed initialization of ADC timings (improves
 analogRead speed by a factor x10)

Discussion:
http://www.djerickson.com/arduino/
http://forum.arduino.cc/index.php?topic=156849
http://forum.arduino.cc/index.php?topic=187693

Fixes #1418
---
 build/shared/revisions.txt                              | 4 ++++
 hardware/arduino/sam/variants/arduino_due_x/variant.cpp | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/build/shared/revisions.txt b/build/shared/revisions.txt
index 5573bf458..70d3bf5dc 100644
--- a/build/shared/revisions.txt
+++ b/build/shared/revisions.txt
@@ -7,6 +7,10 @@ ARDUINO 1.5.5 BETA
 * sam: Fixed SPI initialization (when using extended API and multiple CS)
 * avr: Fixed behavior of EthernetClient::flush()
 
+[core]
+* sam: Fixed wrong initialization for ADC timings (analogRead speed Arduino DUE improved by a factor x10)
+       (http://www.djerickson.com/arduino/)
+
 ARDUINO 1.5.4 BETA 2013.09.10
 
 [ide]
diff --git a/hardware/arduino/sam/variants/arduino_due_x/variant.cpp b/hardware/arduino/sam/variants/arduino_due_x/variant.cpp
index ab43675ab..fbf283fe0 100644
--- a/hardware/arduino/sam/variants/arduino_due_x/variant.cpp
+++ b/hardware/arduino/sam/variants/arduino_due_x/variant.cpp
@@ -433,7 +433,7 @@ void init( void )
 
   // Initialize Analog Controller
   pmc_enable_periph_clk(ID_ADC);
-  adc_init(ADC, SystemCoreClock, ADC_FREQ_MAX, ADC_STARTUP_FAST);
+  adc_init(ADC, SystemCoreClock, ADC_FREQ_MAX, /*ADC_STARTUP_FAST*/ 3);
   adc_configure_timing(ADC, 0, ADC_SETTLING_TIME_3, 1);
   adc_configure_trigger(ADC, ADC_TRIG_SW, 0); // Disable hardware trigger.
   adc_disable_interrupt(ADC, 0xFFFFFFFF); // Disable all ADC interrupts.