Build a cheap GPS precision clock

How to build a cheap gps precision clock, based on a Stm32F103 microcontroller and the internal real time clock module and a 32768 hz quartz crystal. For obtaining a real precision, i have used a gps module for providing reference clock as a comparison with the mcu’s internal rtc clock. In this video i am explaining : How to compensate the crystal's frequency shift due to circuit capacitances How to measure the real deift How to adjust the compensation factor. Content overview 00:00 - RTC Clock drift 00:39 - Overview of the main components 01:15 - Calculate drift in PPM units 02:00 - Measure the trace stray capcitance using RLC meter. 02:50 - How to tune the circuit capacitance to match the cristal’s load capacitance. 03:28 - How to Measure the RTC output frequency using a frequency counter. 04:34 - how to compensate the ppm drift, and how to select the compensation factor for stm32f1 05:18 - Usage of a GPS module to compare the RTC timing, and see actual results in terms of deviation.