#include <avr/io.h>
#include <inttypes.h>
//C is incomplete; there's no port A
//B and D are 8 bit ports
//AtoD is on port C
int main(){
 int b, b7, b6, b67, up=0, down=0, normal=1;
 long k, l, m, n;
 DDRD=0xff;
 DDRB=0x00;
 for (k=0;k<1000000;k++); // a million is approx. 8 seconds
 for (k=0;k<75;k++) { // begin flash LED0 75 times
  PORTD=0x01; // port D LEDs start out low; set to high for first time
  for (l=0;l<3000;l++);
  PORTD=0x00;
  for (l=0;l<3000;l++);
 } // end flash LED0 75 times
 while(1){
  b=PINB;
  //if (lsb==0) b=0xaa; //  if (lsb==128) b=0x00;
  b7 = (b<<7); // 0 if clear; 128 if set
  b67 = (b<<6);
  b6 = (b67)>>7; // 0 if clear; 1 if set
  if (b7 > 0) { // go into up mode
   if (normal) {
    PORTD=0x04; // turn on bit 2 for ">"
    for (k=0;k<3000;k++); // wait
   }
   up=1; normal=0; down=0;   
  }
  if (b6 > 0) { // go into down mode
   if (normal) {
    PORTD=0x08; // turn on bit 3 for "<"
    for (k=0;k<3000;k++); // wait
    up=0; normal=0; down=1;
   }
  }
  if ((b6==0)&&(b7==0)) { // go to normal
   if (down) {
    PORTD=0x04; // turn on bit 2 for ">"
    up=0; normal=1; down=0;
   }
   if (up) {
    PORTD=0x08; // turn on bit 3 for "<"
    up=0; normal=1; down=0;
   }
  }
 }
}