enable blinking dots

also change gps status led: blinking indicates gps status received
blinking short on/long off -> last status has no time signal
blinking long on/short off -> last status has time signal

code/src/main.c

@@ -72,17 +72,19 @@ int main(void){
     setup();
 
     while(1){
-        _delay_ms(200);
-
         check_dip_switches();
 
         uint8_t clock[3];
+        cli();
         DS3231_read(clock);
+        sei();
         for(uint8_t i=0; i < 3; i++){
             SR_Buffer[5-(2*i)] = number_Font[clock[i] & 0x0F];
             SR_Buffer[5-(2*i)-1] = number_Font[(clock[i] & 0xF0)>>4];
         }
+        PORTC = (PORTC & (~DOT)) | (clock[0]%2) << 4; // blink dots
         print_SR_Buffer();
+        _delay_ms(100);
     }
 }
 
@@ -99,7 +101,6 @@ void check_dip_switches() {
 }
 
 void setup(){
-
     DDRA =   ENABLE_TUBE_SUPPLY;
 
     DDRB =   STATUS_LED_B
@@ -190,6 +191,7 @@ ISR(INT1_vect) {
 
 ISR(USART0_RX_vect)
 {
+    PORTB ^= STATUS_LED_C;
     static char async_input_buffer[RX_INPUT_BUFFER_SIZE];
     static uint8_t async_buffer_pointer = 0;