added button handling via polling

src/button_poll/button.cpp

@@ -0,0 +1,47 @@
+//
+// Created by servostar on 27.10.23.
+//
+
+#include "button.h"
+
+// ---------------------------------------
+//
+// DDR set bit of port to either input or output
+// PORTx set bit of port value
+// PINx read voltage of bit of port D
+
+#ifdef BUTTON_POLL
+
+void init() {
+    // ---------------------------------------
+    // set Port B to output
+    // we will write through B5
+    SET_OUTPUT(DDRB, DDB5);
+    CLR_BIT(PORTB, DDB5);
+
+    // ---------------------------------------
+    // setup input port
+    // we will read through D2/D3
+
+    // set Port D to input (bit 2/3, remember bit 0/1 are for UART)
+    SET_INPUT(DDRD, DDD2);
+    SET_INPUT(DDRD, DDD3);
+    // put 5V on input (make it pull up resistor)
+    SET_BIT(PORTD, DDD2);
+    SET_BIT(PORTD, DDD3);
+}
+
+void loop() {
+
+    // poll voltage of pin 2 of port D
+    if (!GET_BIT(PIND, PIND2)) {
+        SET_BIT(PORTB, DDB5);
+    }
+
+    // poll voltage of pin 3 of port D
+    if (!GET_BIT(PIND, PIND3)) {
+        CLR_BIT(PORTB, DDB5);
+    }
+}
+
+#endif

src/button_poll/button.h

@@ -0,0 +1,13 @@
+//
+// Created by servostar on 27.10.23.
+//
+
+#ifndef ARDUINO_BUTTON_H
+#define ARDUINO_BUTTON_H
+
+#include "prelude.h"
+
+void init();
+void loop();
+
+#endif //ARDUINO_BUTTON_H

src/main.cpp

@@ -2,9 +2,11 @@
 extern void init();
 extern void loop();
 
-#include "blink/blink.h"
+//#include "blink/blink.h"
+#include "button_poll/button.h"
 
-#define BLINK
+//#define BLINK
+#define BUTTON_POLL
 
 int main() {
     init();