Would you consider connecting an IC with a dual-speed oscillator and a power-on reset to your MCU? This is what MAX7378 does. This is a good replacement for ceramic resonators, crystals, and other oscillator modules, and discrete reset circuits. The good thing here is that at any time, you can select either low-frequency 32.768kHz or a high frequency from range 600kHz to 10MHz.The clock frequency can be switched at any time without glitches.
![MAX7378.PNG MAX7378](https://scienceprog.com/wp-content/uploads/2021/01/image-115.png)
MAX7378 can be powered from 2,7V to 5,5V, so it is suitable for most MCU types. Comparing to Crystal resonators, it is resistive to vibrations and EMI. It is a good solution for the automotive and industrial environment. High-frequency oscillator error reaches ±2% at 25°C at 5V power supply. In other words, speaking oscillator frequency stability is about ±325ppm (when crystal stability is from ±10ppm to ±100ppm). So it doesn’t correspond to crystal accuracy, but it suits most non-time-critical applications. 32.768kHz oscillator is more accurate with an error of 1%, but it still a bit much for time measurements.
Reset circuitry takes care that reset will occur after 100us after clock startup. Reset output is available in three different options: two of them are push-pull types (active LOW or active HIGH), and the third one is open drain and requires an external pull-up resistor (dashed in the picture below).
![MAX7378_to_MCU.PNG](https://scienceprog.com/wp-content/uploads/2021/01/image-116.png)
The reset signal becomes active if the voltage drops below the threshold. IC is coated in the small 8-pin package and has dimensions of only 3,05×5,03mm, including pins.