A complete range of Digital Clock is shown in Figure 1, equipped with 4 pieces of 7 segment LED display to display the time, consists of dozens of hours numbers, hours, tens of minutes and unit minutes. SW1 and SW2 button is used to set the display time, when SW1 is pressed on the display clock rate will increase every second, while SW2 is used to adjust the display digit minutes in the same way.
12 MHz crystal and capacitors C1 and C2 form a series of working frequency oscillator generating AT89C2051, this series is a series of raw, meaning that form the oscillator circuit is always like this for all series AT89C51, except for purposes other crystal values are probably different.
12 MHz crystal and capacitors C1 and C2 form a series of working frequency oscillator generating AT89C2051, this series is a series of raw, meaning that form the oscillator circuit is always like this for all series AT89C51, except for purposes other crystal values are probably different.