Using only 2 capacitors, 3 resistors, 4 seven-segment Display, 1 xtal, 2 switches n.o. and 1 Microcontroller PIC, you can build this Digital Led Clock. you can use common anode or common cathode display, just select the display type. Here is the pinout information: Pin 3 defines the display type. If you will use common cathode display, connect to negative. For common anode, connect to positive. Here is a example circuit:
Please note: the pin 4 requieres a 10k resistor ONLY for 16F84. On 16F628 is not connected. The minutes displays are upside down. For the capacitors, I used 30pf. You have to read the xtal manufacturer specifications to know the capacitor value recommended. Short connections on xtal is a must to keep accuracy.