diff --git a/include/bits.h b/include/bits.h
new file mode 100644
index 0000000..83ed524
--- /dev/null
+++ b/include/bits.h
@@ -0,0 +1,16 @@
+//
+// Created by servostar on 27.10.23.
+//
+
+#ifndef ARDUINO_BITS_H
+#define ARDUINO_BITS_H
+
+#define SET_BIT(field, idx) ((field) |= (1 << (idx)))
+#define CLR_BIT(field, idx) ((field) &= ~(1 << (idx)))
+#define TOG_BIT(field, idx) ((field) ^= (1 << (idx)))
+#define GET_BIT(field, idx) (((field) >> idx) & 0x1)
+
+#define SET_OUTPUT(port, pin) SET_BIT(port, pin)
+#define SET_INPUT(port, pin) CLR_BIT(port, pin)
+
+#endif //ARDUINO_BITS_H
diff --git a/include/interrupt.h b/include/interrupt.h
new file mode 100644
index 0000000..31fd23e
--- /dev/null
+++ b/include/interrupt.h
@@ -0,0 +1,17 @@
+//
+// Created by servostar on 27.10.23.
+//
+
+#ifndef ARDUINO_INTERRUPT_H
+#define ARDUINO_INTERRUPT_H
+
+#define LOW     0b00
+#define CHANGE  0b01
+#define FALLING 0b10
+#define RISING  0b11
+
+#define SET_INTERRUPT_MODE(index, mode) EICRA = (EICRA & (252 << (index) * 2)) | (mode) << (index) * 2
+#define ENABLE_INTERRUPT(index) SET_BIT(EIMSK, index)
+#define DISABLE_INTERRUPT(index) CLR_BIT(EIMSK, index)
+
+#endif //ARDUINO_INTERRUPT_H
diff --git a/include/prelude.h b/include/prelude.h
new file mode 100644
index 0000000..966fed7
--- /dev/null
+++ b/include/prelude.h
@@ -0,0 +1,19 @@
+//
+// Created by servostar on 27.10.23.
+//
+
+#ifndef ARDUINO_PRELUDE_H
+#define ARDUINO_PRELUDE_H
+
+// set clock frequency to 16MHz
+#define F_CPU 16000000UL
+
+#include "avr/io.h"
+#include "avr/interrupt.h"
+#include "util/delay.h"
+
+// custom header files
+#include "bits.h"
+#include "interrupt.h"
+
+#endif //ARDUINO_PRELUDE_H
diff --git a/src/blink/blink.cpp b/src/blink/blink.cpp
new file mode 100644
index 0000000..3c44d5a
--- /dev/null
+++ b/src/blink/blink.cpp
@@ -0,0 +1,21 @@
+//
+// Created by servostar on 27.10.23.
+//
+
+#include "blink.h"
+
+#ifdef BLINK
+
+void init() {
+    DDRB = 0x20;
+    PORTB = 0x20;
+}
+
+void loop() {
+    PORTB |= 0x20;
+    _delay_ms(500);
+    PORTB &= ~0x20;
+    _delay_ms(500);
+}
+
+#endif
\ No newline at end of file
diff --git a/src/blink/blink.h b/src/blink/blink.h
new file mode 100644
index 0000000..02d2cf7
--- /dev/null
+++ b/src/blink/blink.h
@@ -0,0 +1,13 @@
+//
+// Created by servostar on 27.10.23.
+//
+
+#ifndef ARDUINO_BLINK_H
+#define ARDUINO_BLINK_H
+
+#include "prelude.h"
+
+void init();
+void loop();
+
+#endif //ARDUINO_BLINK_H
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..ca67b9f
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,15 @@
+
+extern void init();
+extern void loop();
+
+#include "blink/blink.h"
+
+#define BLINK
+
+int main() {
+    init();
+
+    for (;;) {
+        loop();
+    }
+}
\ No newline at end of file