Hi, my circuit is composed from a PIC16F15345 microcontroller and a MCP79411 RTC chip, connected with i2c, it has an own 32.768 crystal. The 16F15345 also drives deprez meters and LEDs with PWM signals. While the power of the main circuit is switched off, the RTC runs correctly (precise timing) from its backup 3V battery. But activating the power of the PIC and the PWM driving, the RTC has lost its correct operation, delaying 30 minutes per 12 hour! Any idea to fix is accepted...
Thanks, the recommendations are clear, but to easy to realize on a prototype board, check the attached photo. So it is not the best one, additionally the RTC chip is soldered into a SOIC/DIP PCB. But similar layout worked well in other boards. Only if a PWM is running, I have the problem. Can be the root cause the interference between the frequency of the RTC osc (32.768 Hz) and the used PWM period=32msec (31.25kHz)? May I try with totally different PWM period?
Thanks, the recommendations are clear, but to easy to realize on a prototype board, check the attached photo. So it is not the best one, additionally the RTC chip is soldered into a SOIC/DIP PCB. But similar layout worked well in other boards. Only if a PWM is running, I have the problem. Can be the root cause the interference between the frequency of the RTC osc (32.768 Hz) and the used PWM period=32msec (31.25kHz)? May I try with totally different PWM period?
