write gps time to rtc

code/inc/DS3231.h

@@ -4,5 +4,6 @@
 #include <avr/io.h>
 
 uint32_t DS3231_read(void);
+void DS3231_write(uint8_t inbuffer[3]);
 
 #endif

code/src/DS3231.c

@@ -15,3 +15,12 @@ uint32_t DS3231_read(){
     i2c_stop();
     return ((uint32_t)std<<16) | ((uint32_t)min<<8) | sec;
 }
+
+void DS3231_write(uint8_t inbuffer[3]){
+    i2c_start_wait(0xD0);
+    i2c_write(0x00);
+    i2c_write(inbuffer[0]);
+    i2c_write(inbuffer[1]);
+    i2c_write(inbuffer[2]);
+    i2c_stop();
+}

code/src/main.c

@@ -42,14 +42,14 @@ uint8_t parse_nmea_gps(char input_string[RX_INPUT_BUFFER_SIZE], uint8_t output_b
         }
 
         // craft bcd values
-        output_buffer[0]  = (time[0] - 48) << 4;
+        output_buffer[2]  = (time[0] - 48) << 4;
-        output_buffer[0] |= time[1] - 48;
+        output_buffer[2] |= time[1] - 48;
 
         output_buffer[1]  = (time[2] - 48) << 4;
         output_buffer[1] |= time[3] - 48;
 
-        output_buffer[2]  = (time[4] - 48) << 4;
+        output_buffer[0]  = (time[4] - 48) << 4;
-        output_buffer[2] |= time[5] - 48;
+        output_buffer[0] |= time[5] - 48;
 
         return 0;
     }
@@ -262,8 +262,10 @@ ISR(USART0_RX_vect)
         async_buffer_pointer=0;
         PORTB ^=STATUS_LED_C;
         uint8_t test[3];
-        if(!parse_nmea_gps(async_input_buffer, test))
+        if(!parse_nmea_gps(async_input_buffer, test)){
-            printf("parse: %x %x %x\n\r", test[0], test[1], test[2]); 
+            printf("parse: %x %x %x\n\r", test[2], test[1], test[0]); 
+            DS3231_write(test);
+        }
     }
 }