From 8625fa013eb7b835215d7089ae8f182e47b04136 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Fri, 11 Mar 2016 20:17:21 +0100
Subject: Show timeout message when contact is lost during flashing

---
 src/static_patterns.h |  6 ++++++
 src/system.cc         | 25 +++++++++++++++++++++++++
 src/system.h          |  2 ++
 3 files changed, 33 insertions(+)

diff --git a/src/static_patterns.h b/src/static_patterns.h
index b1147a9..155c68e 100644
--- a/src/static_patterns.h
+++ b/src/static_patterns.h
@@ -41,4 +41,10 @@ const uint8_t PROGMEM emptyPattern[] = {
 	'e', ' ', 'i', 's', ' ', 'e', 'm', 'p', 't', 'y'
 };
 
+const uint8_t PROGMEM timeoutPattern[] = {
+	0x10, 0x0a,
+	0x20, 0x00,
+	' ', 2, ' ', 'T', 'i', 'm', 'e', 'o', 'u', 't'
+};
+
 #endif /* STATIC_PATTERNS_H_ */
diff --git a/src/system.cc b/src/system.cc
index d7d0f71..759c58e 100644
--- a/src/system.cc
+++ b/src/system.cc
@@ -140,6 +140,12 @@ void System::receive(void)
 				rxExpect = PATTERN1;
 				storage.reset();
 				loadPattern_P(flashingPattern);
+				MCUSR &= ~_BV(WDRF);
+				cli();
+				// watchdog interrupt after 4 seconds
+				WDTCSR = _BV(WDCE) | _BV(WDE);
+				WDTCSR = _BV(WDIE) | _BV(WDP3);
+				sei();
 			} else {
 				rxExpect = NEXT_BLOCK;
 			}
@@ -154,6 +160,7 @@ void System::receive(void)
 				current_anim_no = 0;
 				loadPattern(0);
 				rxExpect = START1;
+				wdt_disable();
 			}
 			break;
 		case PATTERN1:
@@ -176,6 +183,7 @@ void System::receive(void)
 		case HEADER2:
 			rxExpect = META1;
 			remaining_bytes += rx_byte;
+			wdt_reset();
 			break;
 		case META1:
 			rxExpect = META2;
@@ -314,7 +322,24 @@ void System::shutdown()
 	rxExpect = START1;
 }
 
+void System::handleTimeout()
+{
+	rxExpect = START1;
+	current_anim_no = 0;
+	loadPattern_P(timeoutPattern);
+}
+
 ISR(PCINT1_vect)
 {
 	// we use PCINT1 for wakeup, so we need an (in this case empty) ISR for it
 }
+
+ISR(WDT_vect)
+{
+	/*
+	 * Modem transmission was interrupted without END byte. Reset state
+	 * machine and show timeout message.
+	 */
+	wdt_disable();
+	rocket.handleTimeout();
+}
diff --git a/src/system.h b/src/system.h
index 3cb74b0..870ec35 100644
--- a/src/system.h
+++ b/src/system.h
@@ -75,6 +75,8 @@ class System {
 		 * whenever the system is woken up by an interrupt.
 		 */
 		void loop(void);
+
+		void handleTimeout(void);
 };
 
 extern System rocket;
-- 
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