From 6ae1a1723561266767ed1ba39ae61c35ea263162 Mon Sep 17 00:00:00 2001
From: Zach Eveland <zeveland@blacklabel-development.com>
Date: Thu, 19 Apr 2012 15:52:16 -0400
Subject: [PATCH] bugfix for configuring PWM on D6 and D13 too early.  (thanks
 to Limor Fried)

was starting PWM on these pins too soon - in init() instead of when analogWrite() was called.  as a result doing output on port registers directly failed.
---
 cores/arduino/wiring.c        | 4 ----
 cores/arduino/wiring_analog.c | 6 ++++++
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/cores/arduino/wiring.c b/cores/arduino/wiring.c
index fb447eb..ac8bb6f 100644
--- a/cores/arduino/wiring.c
+++ b/cores/arduino/wiring.c
@@ -280,10 +280,6 @@ void init()
 #endif
 
 #if defined(TCCR4A) && defined(TCCR4B) && defined(TCCR4D) /* beginning of timer4 block for 32U4 and similar */
-	sbi(TCCR4A, COM4A1);	// clear channel A on output compare match
-	cbi(TCCR4A, COM4A0);
-	sbi(TCCR4C, COM4D1);	// clear channel D on output compare match
-	cbi(TCCR4C, COM4D0);
 	sbi(TCCR4B, CS42);		// set timer4 prescale factor to 64
 	sbi(TCCR4B, CS41);
 	sbi(TCCR4B, CS40);
diff --git a/cores/arduino/wiring_analog.c b/cores/arduino/wiring_analog.c
index c06cad4..0e9881f 100644
--- a/cores/arduino/wiring_analog.c
+++ b/cores/arduino/wiring_analog.c
@@ -210,6 +210,9 @@ void analogWrite(uint8_t pin, int val)
 			case TIMER4A:
 				//connect pwm to pin on timer 4, channel A
 				sbi(TCCR4A, COM4A1);
+				#if defined(COM4A0)		// only used on 32U4
+				cbi(TCCR4A, COM4A0);
+				#endif
 				OCR4A = val;	// set pwm duty
 				break;
 			#endif
@@ -234,6 +237,9 @@ void analogWrite(uint8_t pin, int val)
 			case TIMER4D:				
 				// connect pwm to pin on timer 4, channel D
 				sbi(TCCR4C, COM4D1);
+				#if defined(COM4D0)		// only used on 32U4
+				cbi(TCCR4C, COM4D0);
+				#endif
 				OCR4D = val;	// set pwm duty
 				break;
 			#endif