DCF UART USART generator RTC GPS atmega avr as4 you can change time and date by USART commands, you can change prescalers and TCNT1 for T1 by USART commands PB2, PB5 - blinking LED as T1, PB1 - DCF output USART -9600, 8 bit , 1 stopbit , parity none
TO DO : RTC time