Just one PIC to use it as counter with multiple functions. Here is the pin information:
- CLEAR/COUNT – GND to clear count, VSS to count.
- SAVE COUNT – GND start from zero on power up, VSS continue last count.
- C CATHODE/C ANODE – GND to use COMMON CATHODE Display, VSS to use COMMON ANODE.
- INPUT – Signal in, pulses to count.
As you can see, now you can use any 7 Segment Led Display. Just connect the pin C CATHODE/C ANODE to the respective signal. The pin SAVE COUNT can be used to save the count and power off the circuit. When you power on the circuit, the display will resume the counting.
An example how to use it using common cathode displays, no resume count on power up and free runing:
Every time when you turn ON the circuit, will display 0000. Each pulse in the INPUT pin will increase the count. You can replace the switch with a LDR, reed switch or any kind of sensor.
Use RED displays for better performance, Green displays may need 5.5 volts.
You can use this counter with one, two, three or four digits, just remove the displays that doesn’t need to be used. Also, you can use transistors to increase the current for each display.
For more detail: An Easy to build & multifunctional counter with 7-Segment Led Display using PIC16F628 microcontroller