1 files changed, 74 insertions, 0 deletions
diff --git a/src/system.cc b/src/system.cc
new file mode 100644
index 0000000..8b02275
--- /dev/null
+++ b/src/system.cc
@@ -0,0 +1,74 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/wdt.h>
+#include <util/delay.h>
+#include <stdlib.h>
+
+#include "display.h"
+#include "modem.h"
+#include "system.h"
+
+#define SHUTDOWN_THRESHOLD 2048
+
+System rocket;
+
+extern volatile uint8_t disp[8];
+
+void System::loop()
+{
+	// both buttons are pressed
+	if ((PINC & (_BV(PC3) | _BV(PC7))) == 0) {
+		// naptime!
+		// But not before both buttons have been pressed for
+		// SHUTDOWN_THRESHOLD * 0.256 ms. And then, not before both have
+		// been released, because otherwise we'd go te sleep when
+		// they're pressed and wake up when they're released, which
+		// isn't really the point here.
+
+		if (want_shutdown < SHUTDOWN_THRESHOLD) {
+			want_shutdown++;
+		}
+		else {
+
+			// turn off display to indicate we're about to shut down
+			display.turn_off();
+
+			// wait until both buttons are released
+			while (!((PINC & _BV(PC3)) && (PINC & _BV(PC7)))) ;
+
+			// and some more to debounce the buttons
+			_delay_ms(10);
+
+			// actual naptime
+
+			// enable PCINT on PC3 (PCINT11) and PC7 (PCINT15) for wakeup
+			PCMSK1 |= _BV(PCINT15) | _BV(PCINT11);
+			PCICR |= _BV(PCIE1);
+
+			// go to power-down mode
+			SMCR = _BV(SM1) | _BV(SE);
+			asm("sleep");
+
+			// execution will resume here - disable PCINT again.
+			// Don't disable PCICR, something else might need it.
+			PCMSK1 &= ~(_BV(PCINT15) | _BV(PCINT11));
+
+			// turn on display
+			display.turn_on();
+
+			want_shutdown = 0;
+		}
+	}
+	else {
+		want_shutdown = 0;
+	}
+
+	if (modem.buffer_available()) {
+		disp[0] = modem.buffer_get();
+	}
+}
+
+ISR(PCINT1_vect)
+{
+	// we use PCINT1 for wakeup, so we should catch it here (and do nothing)
+}