From 79481252081da0bdc4501cf039c060efcdf85c95 Mon Sep 17 00:00:00 2001
From: Zach Eveland <zeveland@blacklabel-development.com>
Date: Tue, 14 Feb 2012 12:17:30 -0500
Subject: Leonardo now checks whether bootloader should be run after a WDT
 event.

Before the sketch initiates an auto-reset for upload it pokes a magic word into a specific RAM address.  On starting the bootloader checks this address.  If it finds the magic word it knows the bootloader code should run. If not it jumps straight back to sketch.

Test in a sketch by adding to setup():
wdt_enable(WDTO_2S);

Sketch should upload, start, run for two seconds, WDT, and sketch should restart (not bootloader).

Had to cut out unused descriptor code to make the bootloader still fit in 4k.
---
 bootloaders/caterina_LUFA/Caterina.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'bootloaders/caterina_LUFA/Caterina.c')

diff --git a/bootloaders/caterina_LUFA/Caterina.c b/bootloaders/caterina_LUFA/Caterina.c
index b6fbd9b..d4dbb7b 100755
--- a/bootloaders/caterina_LUFA/Caterina.c
+++ b/bootloaders/caterina_LUFA/Caterina.c
@@ -64,6 +64,9 @@ uint16_t RxLEDPulse = 0; // time remaining for Rx LED pulse
 /* Bootloader timeout timer */
 uint16_t Timeout = 0;
 
+uint16_t bootKey = 0x7777;
+volatile uint16_t *const bootKeyPtr = (volatile uint16_t *)0x0A00;
+
 void StartSketch(void)
 {
 	cli();
@@ -118,6 +121,11 @@ int main(void)
 	if (mcusr_state & (1<<PORF) && pgm_read_word(0) != 0xFFFF) {		
 		StartSketch();
 	}
+	uint16_t bootKeyPtrVal = *bootKeyPtr;
+	*bootKeyPtr = 0;
+	if ((mcusr_state & (1<<WDRF)) && (bootKeyPtrVal != bootKey) && (pgm_read_word(0) != 0xFFFF)) {	
+		StartSketch();
+	}
 	
 	/* Setup hardware required for the bootloader */
 	SetupHardware();
-- 
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