About Digital Clock using PIC16F84A

Hey guys i have a clock. PIC is code protected. But problem is after run some hours it has 4 or 5 minuts time gap. So what can I do ( without touching the CHIP )

Replace one of the capacitors connected to the crystal with a ceramic trimmer capacitor of 15-30pf range, or thereabouts, then adjust the oscillator frequency up or down as required. I use my Icom 756PROII reciever with built-in 0.5ppm timebase to 'listen' to the oscillator frequency while tuning it but if you don't have a receiver then you might make small adjustments over time while keeping track of the effect on the clock.

@pasanlaksiri have you found a pic16f84a digital clock in the net?? would you share em here?? please.

jofp said:

@pasanlaksiri have you found a pic16f84a digital clock in the net?? would you share em here?? please.

Click to expand...

Hey bro go here https://www.electro-tech-online.com/threads/very-simple-led-clock-using-16f84a-or-16f628a.27545/?highlight=simple

Its working perfectly

pasanlaksiri said:

Hey guys i have a clock. PIC is code protected. But problem is after run some hours it has 4 or 5 minuts time gap. So what can I do ( without touching the CHIP )

Click to expand...

You try to measure the clock frequency of the crystal used with a known standard frequency counter-- trim the capacitors to nullyfy the difference of frequency compared to the marking on the crystal.

hi Friends
Any one here pzl help me i want to create 12 or 24 clock with using pic 16f84a. i try create it but i cant it create if you like help me this plz send me program code .hex or .asm file and circuit drg. or helfull web site my e-mail is abcggn@gmail.com