From 4813472a201f06b1f7db6b75ea07e751ca3a95a1 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Sun, 12 Mar 2017 12:36:46 +0100
Subject: [PATCH] The Sphinx v0.9

---
 sphinx/sphinx.c | 110 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 99 insertions(+), 11 deletions(-)

diff --git a/sphinx/sphinx.c b/sphinx/sphinx.c
index 7355d0b..5f3e3f2 100644
--- a/sphinx/sphinx.c
+++ b/sphinx/sphinx.c
@@ -1,5 +1,5 @@
 /*
- *	Asking Riddles at the Entrance to Garage
+ *	The Sphinx -- A Device for Asking Riddles at the Entrance to the Garage
  *
  *	(c) 2017 Martin Mares <mj@ucw.cz>
  */
@@ -9,19 +9,24 @@
  *
  *			+-------------------+
  *	                | RESET*        VCC |
- *	button         	| PB3           SCK |
+ *	button*        	| PB3           SCK |
  *	output       	| PB4          MISO |
  *			| GND      PB0=MOSI |	diagnostic LED*
  *			+-------------------+
+ *
+ *	Note that MOSI is used for programming, so the LED is connected
+ *	via jumper, which must be open during programming.
  */
 
 #define F_CPU 1200000UL
 
+#include <avr/interrupt.h>
 #include <avr/io.h>
 #include <avr/sleep.h>
 #include <util/delay.h>
 
 typedef uint8_t byte;
+typedef uint16_t u16;
 
 #define B(x) (1U<<(x))
 
@@ -33,32 +38,115 @@ static void sleep(uint16_t millisec)
 	}
 }
 
+static byte out_pulse;
+#define OUT_PULSE_WIDTH 100
+static byte debounce;
+#define DEBOUNCE_THRESHOLD 3
+static byte pressed;
+static u16 press_timer;
+#define LONG_PRESS 500
+static byte second_timer;
+static byte unlocked;
+#define UNLOCK_SECONDS 20
+
+ISR(TIM0_COMPA_vect)
+{
+	if (out_pulse) {
+		if (!--out_pulse)
+			PORTB &= ~B(PB4);
+	}
+
+	if (!second_timer) {
+		second_timer = 100;
+		if (unlocked)
+			unlocked--;
+	}
+	second_timer--;
+
+	if (PINB & B(PB3)) {
+		// Switch open
+		if (debounce)
+			debounce--;
+		else
+			pressed = 0;
+	} else {
+		// Switch closed
+		if (debounce < DEBOUNCE_THRESHOLD)
+			debounce++;
+		else
+			pressed = 1;
+	}
+
+	if (unlocked) {
+		if (!(second_timer & 7))
+			PORTB ^= B(PB0);
+		if (pressed) {
+			if (out_pulse < 2)
+				out_pulse = 2;
+			PORTB |= B(PB4);
+			unlocked = UNLOCK_SECONDS;
+		}
+	} else {
+		if (!pressed) {
+			PORTB |= B(PB0);
+			press_timer = 0;
+		} else {
+			PORTB &= ~B(PB0);
+			if (press_timer < LONG_PRESS) {
+				press_timer++;
+				if (press_timer == LONG_PRESS) {
+					out_pulse = OUT_PULSE_WIDTH;
+					PORTB |= B(PB4);
+					unlocked = UNLOCK_SECONDS;
+				}
+			}
+		}
+	}
+}
+
 int main(void)
 {
-	DDRB |= B(PB0);			// PB0: output
-	DDRB |= B(PB4);			// PB4: output
-	PORTB &= ~B(PB3);		// PB3: input, no pullup
+	// PB0: output for diagnostic LED
+	DDRB |= B(PB0);
+
+	// PB3: button input, needs pull up
+	PORTB |= B(PB3);
+
+	// PB4: output to control the gate
+	PORTB &= ~B(PB4);
+	DDRB |= B(PB4);
 
 	for (byte i=0; i<5; i++) {
 		PORTB &= ~B(PB0);
-		sleep(100);
+		sleep(50);
 		PORTB |= B(PB0);
-		sleep(100);
+		sleep(50);
 	}
 
+#if 0
+	// Copy mode
 	for (;;) {
 		sleep(10);
 		if (PINB & B(PB3)) {
-			PORTB &= ~B(PB0);
-			PORTB |= B(PB4);
-		} else {
 			PORTB |= B(PB0);
 			PORTB &= ~B(PB4);
+		} else {
+			PORTB &= ~B(PB0);
+			PORTB |= B(PB4);
 		}
 	}
+#endif
+
+	// Set up timer interrupt
+	TCCR0A = 0x02;			// No OC pins, clear on compare
+	TCCR0B = 0x05;			// Run at CLK_IO / 1024
+	OCR0A = 11;			// Approximately once in 10ms
+	TIMSK0 = B(OCIE0A);		// Interrupt on compare
+	sei();
 
+	// Sleep well, my little sphinx
 	for (;;) {
-		set_sleep_mode(SLEEP_MODE_PWR_DOWN);
+		set_sleep_mode(SLEEP_MODE_IDLE);
 		sleep_mode();
 	}
 }
-- 
2.39.2