Started following some tutorial on att85 usi. Downloaded example code from make avr book.

Make AVR Examples/Chapter06_Digital-Input/simpleButton/simpleButton.c

@@ -0,0 +1,27 @@
+/*
+   Demo of the simplest on/off button code
+   Button connected to PD2
+   LEDs connected to PB0..PB7
+*/
+
+// ------- Preamble -------- //
+#include <avr/io.h>
+#include <util/delay.h>
+
+int main(void) {
+  // -------- Inits --------- //
+  PORTD |= (1 << PD2);  /* initialize pullup resistor on our input pin */
+  DDRB = 0xff;                           /* set up all LEDs for output */
+
+  // ------ Event loop ------ //
+  while (1) {
+    if (bit_is_clear(PIND, PD2)) {            /* look for button press */
+                      /* equivalent to if ((PIND & (1 << PD2)) == 0 ){ */
+      PORTB = 0b00111100;                                   /* pressed */
+    }
+    else {                                              /* not pressed */
+      PORTB = 0b11000011;
+    }
+  }                                                  /* End event loop */
+  return 0;
+}