Updating a 4-digit 7-segment display within a timer interrupt routine on the ATmega328.

01:20 the pins on the chip we will be using
02:20 warning signs for wrong connections
04:00 preparation of the connections, counting wires
06:15 the power supply rails on the breadboard
07:00 starting connecting the wires
09:00 connecting the power supply pins
11:00 connecting the programmer
12:00 testing the connection between programmer and microcontroller
14:00 connecting the wires to port D
16:30 connecting the wires to the segments of the LED display
20:40 connecting the wires between port B and the digit pins
23:00 the code
27:00 the font structure in the code
31:00 the main()-function
32:00 the init()-function
32:45 looking at the control registers of TIMER0
37:00 setting the necessary bits
45:00 the clock prescalers of TIMER0
49:00 handling the interrupt in the ISR()
52:00 compiling the code and uploading

The code template can be found here: https://pastebin.com/bBnz8w3y