lightctrl: use WDT

the CPU seems to get stuck for no apparent reason, right in the middle
of a line on the serial console... weird.  let's enable the WDT as a
temporary band-aid.

1 files changed, 25 insertions, 0 deletions

diff --git a/wdt.c b/wdt.c
new file mode 100644
index 0000000..f815b71
--- /dev/null
+++ b/wdt.c
@@ -0,0 +1,25 @@
+
+static uint8_t wdt_generation __attribute__((section (".noinit")));
+
+static void wdt_init(void)
+{
+	uint8_t temp;
+	/* timed sequence. bit 4: WDCE, bit 3: WDE,
+	 * 0x07 = WDP2 | WDP1 | WDP0 = 2s */
+	asm volatile ("\n\
+WDTCSR	= 0x60\n\
+WDCE	= 4\n\
+WDE	= 3\n\
+		wdr	\n\
+			\n\
+		ldi	%[temp], (1 << WDCE) | (1 << WDE)	\n\
+		sts	WDTCSR, %[temp]				\n\
+			\n\
+		ldi	%[temp], (1 << WDE) | 0x07		\n\
+		sts	WDTCSR, %[temp]				\n\
+	" : [temp] "=r" (temp) :  : "memory");
+
+	if (MCUSR & (1 << WDRF))
+		wdt_generation++;
+}
+