Showing posts with label MAX7219. Show all posts
Showing posts with label MAX7219. Show all posts

Wednesday, August 5, 2015

100MHz frequency counter

Couple of weeks ago I purchased from eBay one of these amazingly cheap an useful modules with MAX7219 LED driver and 8 digit LED display. It is ideal for frequency counter project. The problem was the absence of library for PIC microcontrolers. Luckily, I found a great library for Arduino and I reworked it to be compatible with PIC. The schematic of the frequency counter is actually almost the same as the previous . It uses PIC16F628A microcontroller with external 32.768kHz watch crystal attached to Timer1 to generate 1 second time base. Measured signal is fed to pin3 (RA4) which is counted by Timer0.