A 12 bit latch permits the storage of the information of the counter. The content of the latches is multiplexed and presented serially digit by digit at the output for display. An internal oscillator provide the multiplexing frequency. MC14553 IC schematic. Place a 0.001 m F between pins 3 and 4 to cycle the output.
Level is low for the digit being displayed.
BCD code for the number to be displayed. Raising this line will latch the current count into the output display register. This is like the lapse time on a stop watch. The displayed count will remain although the counter is still counting. To update the displayed number, drop this line low.