From 26f0fff87a85970c61618240710a65a57e682d0e Mon Sep 17 00:00:00 2001
From: Sem van der Hoeven <semmer99@gmail.com>
Date: Wed, 24 Mar 2021 13:24:13 +0100
Subject: [PATCH] [ADD] ultrasonic sensor c and h file

---
 .../ultrasonicSensor/ultrasonic_sensor.c      | 91 +++++++++++++++++++
 .../ultrasonicSensor/ultrasonic_sensor.h      | 12 +++
 2 files changed, 103 insertions(+)
 create mode 100644 Microcontrollers/ultrasonicSensor/ultrasonic_sensor.c
 create mode 100644 Microcontrollers/ultrasonicSensor/ultrasonic_sensor.h

diff --git a/Microcontrollers/ultrasonicSensor/ultrasonic_sensor.c b/Microcontrollers/ultrasonicSensor/ultrasonic_sensor.c
new file mode 100644
index 0000000..430a118
--- /dev/null
+++ b/Microcontrollers/ultrasonicSensor/ultrasonic_sensor.c
@@ -0,0 +1,91 @@
+/*
+ * ultrasonic_sensor.c
+ *
+ * Created: 24-3-2021 13:04:52
+ *  Author: Sem
+ */ 
+
+#define F_CPU 10e6
+
+#include <avr/io.h>
+#include <util/delay.h>
+#include <avr/interrupt.h>
+
+#include "lcd_control.h"
+
+static uint16_t timer_dist = 0;
+
+enum interrupt_status {INTERRUPT_FALLING, INTERRUPT_RISING};
+
+static enum interrupt_status int_stat = INTERRUPT_RISING;
+
+void wait_us(unsigned int us)
+{
+	for(int i = 0; i < us; i++)
+	{
+		_delay_us(1);
+	}
+}
+
+void wait_ms(unsigned int ms)
+{
+	
+	for(int i = 0; i < ms; i++)
+	{
+		_delay_ms(1);
+	}
+}
+void ultrasonic_init()
+{
+	DDRG = 0xFF; // port g all output. pin 0 is trig, the rest is for debug
+	DDRD = 0x00; // port D pin 0 on input. 0 is echo and also interrupt
+	
+	EICRA = 0x03; // interrupt PORTD on pin 0, rising edge
+	
+	EIMSK |= 0x01; // enable interrupt on pin 0 (INT0)
+	
+	TCCR1A = 0b00000000; // initialize timer1, prescaler=256
+	TCCR1B = 0b00001100; // CTC compare A, RUN
+	
+	sei(); // turn on interrupt system
+}
+
+void ultrasonic_send_pulse()
+{
+	PORTG = 0x00; // 10 us low pulse
+	wait_us(10);
+	PORTG = 0x01;
+}
+
+void ultrasonic_handle_interrupt()
+{
+	// if the interrupt was generated on a rising edge (start sending echo)
+	if (int_stat == INTERRUPT_RISING)
+	{
+		// set interrupt pin 0 on PORTD to falling edge
+		EICRA = 0x02;
+		
+		// reset the time in timer1
+		TCNT1 = 0x00;
+		
+		// set interrupt status
+		int_stat = INTERRUPT_FALLING;
+	} else
+	// else if it was generated on a falling edge (end sending echo)
+	{
+		// set interrupt pin 0 on PORTD to rising edge
+		EICRA = 0x03;
+		
+		// read timer1 into time_dist
+		timer_dist = TCNT1;
+		
+		// set interrupt status
+		int_stat = INTERRUPT_RISING;
+	}
+}
+
+uint16_t ultrasonic_get_timer_dist()
+{
+	return timer_dist;
+}
+
diff --git a/Microcontrollers/ultrasonicSensor/ultrasonic_sensor.h b/Microcontrollers/ultrasonicSensor/ultrasonic_sensor.h
new file mode 100644
index 0000000..0981c46
--- /dev/null
+++ b/Microcontrollers/ultrasonicSensor/ultrasonic_sensor.h
@@ -0,0 +1,12 @@
+/*
+ * ultrasonic_sensor.h
+ *
+ * Created: 24-3-2021 13:14:50
+ *  Author: Sem
+ */ 
+
+
+void ultrasonic_init();
+void ultrasonic_send_pulse();
+uint16_t ultrasonic_get_timer_dist();
+void ultrasonic_handle_interrupt();