Matrix user forums

Sir,
I am new to flow code & made a simple program for the ON-OFF timer. I am not using external crystal on my board. I am using standard delay second instruction. What I observed that the timing changes after working for 20 minutes. What can be the problem. I am using 16F690.

Rgds

Hello,

What type of oscillator are you using? Have you set the clock in the project options window to match the speed of your oscillator? Are you using a two speed startup configuration setting?