commit 2c9714c8514a86146c5dc08e9910bf9d99f00912
Author: Pratik <pratik@engineeringbuild.com>
Date:   Fri Apr 3 09:42:37 2026 +1100

    initial avr projects (blink + interrupts)

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea1664e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,15 @@
+# ignore toolchain
+avr8-gnu-toolchain-win32_x86_64/
+avrdude.conf
+# ignore build / binary files
+*.exe
+*.hex
+*.elf
+*.o
+*.map
+*.log
+*.bin
+
+# optional (AVR builds)
+*.lss
+*.eep
\ No newline at end of file
diff --git a/LED Blink Input Output/Makefile b/LED Blink Input Output/Makefile
new file mode 100644
index 0000000..cf4d044
--- /dev/null
+++ b/LED Blink Input Output/Makefile	
@@ -0,0 +1,24 @@
+MCU = atmega328p
+F_CPU = 16000000UL
+CC = C:\Users\sharm\Desktop\our main folder\avrprojects\avr8-gnu-toolchain-win32_x86_64\bin\avr-gcc
+OBJCOPY = C:\Users\sharm\Desktop\our main folder\avrprojects\avr8-gnu-toolchain-win32_x86_64\bin\avr-objcopy
+AVRDUDE = ../avrdude
+AVRDUDE_PROGRAMMER = arduino
+AVRDUDE_PORT = COM8
+AVRDUDE_BAUD = 115200
+
+CFLAGS = -mmcu=$(MCU) -DF_CPU=$(F_CPU) -Os -Wall
+
+all: main.hex
+
+main.elf: main.c delay.h
+	$(CC) $(CFLAGS) main.c -o main.elf
+
+main.hex: main.elf
+	$(OBJCOPY) -O ihex -R .eeprom main.elf main.hex
+
+upload: main.hex
+	$(AVRDUDE) -c $(AVRDUDE_PROGRAMMER) -p $(MCU) -P $(AVRDUDE_PORT) -b $(AVRDUDE_BAUD) -D -U flash:w:main.hex:i
+
+clean:
+	rm -f main.elf main.hex
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diff --git a/LED Blink Input Output/delay.h b/LED Blink Input Output/delay.h
new file mode 100644
index 0000000..db4e991
--- /dev/null
+++ b/LED Blink Input Output/delay.h	
@@ -0,0 +1,35 @@
+#ifndef DELAY_H
+#define DELAY_H
+
+#include <avr/io.h>
+#include <stdint.h>
+
+// Call this ONCE in main() before using delay_ms()
+static inline void timer1_init(void) {
+    // Configure Timer1 in CTC mode
+    TCCR1B |= (1 << WGM12);
+
+    // Set compare match for 1ms delay (16MHz / 64 prescaler)
+    OCR1A = 249;
+
+    // Start Timer1 with prescaler 64
+    TCCR1B |= (1 << CS11) | (1 << CS10);
+
+    // Reset timer count
+    TCNT1 = 0;
+}
+
+// Delay function assumes timer already initialized
+static inline void delay_ms(uint16_t ms) {
+    for (uint16_t i = 0; i < ms; i++) {
+        // Clear compare flag
+        TIFR1 |= (1 << OCF1A);
+
+        // Wait for compare match flag
+        while (!(TIFR1 & (1 << OCF1A))) {
+            // Busy wait
+        }
+    }
+}
+
+#endif // DELAY_H
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diff --git a/LED Blink Input Output/main.c b/LED Blink Input Output/main.c
new file mode 100644
index 0000000..56c22e2
--- /dev/null
+++ b/LED Blink Input Output/main.c	
@@ -0,0 +1,28 @@
+#include "delay.h"
+
+int main(void) {
+  // PC2 as output (LED), PC3 as input (button)
+  timer1_init();
+
+  DDRB |= (1<<PB2);
+  DDRB &= ~(1<<PB3);
+
+  // enable internal pull-up on PC3 (important)
+  PORTB |= (1<<PB3);
+
+  timer1_init();
+
+  while(1) {
+    // Button pressed -> pin reads LOW because of pull-up
+    if (PINB & (1<<PB3)) {
+      for (int i=0;i<=20;i++){
+      PORTB |= (1<<PB2);      // LED ON
+      delay_ms(200);
+      PORTB &= ~(1<<PB2);
+      delay_ms(200);
+     }
+    } else {
+      PORTB &= ~(1<<PB2);     // LED OFF
+    }
+  }
+}
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diff --git a/interrupts/Makefile b/interrupts/Makefile
new file mode 100644
index 0000000..f779a99
--- /dev/null
+++ b/interrupts/Makefile
@@ -0,0 +1,24 @@
+MCU = atmega328p
+F_CPU = 16000000UL
+CC = C:\Users\sharm\Desktop\our main folder\avrprojects\avr8-gnu-toolchain-win32_x86_64\bin\avr-gcc
+OBJCOPY = C:\Users\sharm\Desktop\our main folder\avrprojects\avr8-gnu-toolchain-win32_x86_64\bin\avr-objcopy
+AVRDUDE = ../avrdude
+AVRDUDE_PROGRAMMER = arduino
+AVRDUDE_PORT = COM10
+AVRDUDE_BAUD = 115200
+
+CFLAGS = -mmcu=$(MCU) -DF_CPU=$(F_CPU) -Os -Wall
+
+all: main.hex
+
+main.elf: main.c delay.h
+	$(CC) $(CFLAGS) main.c -o main.elf
+
+main.hex: main.elf
+	$(OBJCOPY) -O ihex -R .eeprom main.elf main.hex
+
+upload: main.hex
+	$(AVRDUDE) -c $(AVRDUDE_PROGRAMMER) -p $(MCU) -P $(AVRDUDE_PORT) -b $(AVRDUDE_BAUD) -D -U flash:w:main.hex:i
+
+clean:
+	rm -f main.elf main.hex
\ No newline at end of file
diff --git a/interrupts/delay.h b/interrupts/delay.h
new file mode 100644
index 0000000..c82fdfa
--- /dev/null
+++ b/interrupts/delay.h
@@ -0,0 +1,35 @@
+#ifndef DELAY_H
+#define DELAY_H
+
+#include <avr/io.h>
+#include <stdint.h>
+
+// Call this ONCE in main() before using delay_ms()
+static inline void timer1_init(void) {
+    // Configure Timer1 in CTC mode
+    TCCR1B |= (1 << WGM12);
+
+    // Set compare match for 1ms delay (16MHz / 64 prescaler)
+    OCR1A = 250;
+
+    // Start Timer1 with prescaler 64
+    TCCR1B |= (1 << CS11) | (1 << CS10);
+
+    // Reset timer count
+    TCNT1 = 0;
+}
+
+// Delay function assumes timer already initialized
+static inline void delay_ms(uint16_t ms) {
+    for (uint16_t i = 0; i < ms; i++) {
+        // Clear compare flag
+        TIFR1 |= (1 << OCF1A);
+
+        // Wait for compare match flag
+        while (!(TIFR1 & (1 << OCF1A))) {
+            // Busy wait
+        }
+    }
+}
+
+#endif // DELAY_H
\ No newline at end of file
diff --git a/interrupts/main.c b/interrupts/main.c
new file mode 100644
index 0000000..ba31c01
--- /dev/null
+++ b/interrupts/main.c
@@ -0,0 +1,35 @@
+#include "delay.h"
+#include <avr/interrupt.h>
+volatile uint8_t flag=0;
+
+int main(void){
+timer1_init();
+  DDRC |= (1<<PC0);                          // PB1 (D9)
+   // prescaler 8
+  DDRD &= ~(1 << PD2);
+  PORTD |= (1 << PD2);
+  EICRA &= ~(1<<ISC00);
+  EICRA |= (1<<ISC01);
+  EIMSK |= (1<<INT0);
+
+  sei();
+  while(1){
+    if(flag){
+
+      flag=0;
+    PORTC |=(1<<PC0); 
+    delay_ms(500); 
+    PORTC &=~(1<<PC0);
+    delay_ms(500);
+    }
+    else{
+      PORTC |=(1<<PC0);
+      delay_ms(50);
+      PORTC &=~(1<<PC0);
+      delay_ms(50);
+    }           // 75%
+  }
+}
+ISR(INT0_vect){
+  flag=1; 
+}
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