Sure, Linux realtime threads is one way to generate high frequency signals with Raspberry Pi reliably, but what are other methods mentioned out of the Internet? Oh, interesting, ChibiOS/RT is a realtime operating system that runs on Raspberry Pi and also Arduino. One portable operating system to write all your realtime code in.
20200304/DuckDuckGo raspberry pi generate microsecond one shot pulse
20200304/https://raspberrypi.stackexchange.com/questions/19765/rpi-gpio-as-a-high-speed-square-wave-generator
20200304/http://www.stevebate.net/chibios-rpi/GettingStarted.html
How do you build a power-on RESET circuit? The simplest method involves a capacitor and a comparator, but this won’t quite work if your power supply has a ramp-up time that is similar to the capacitor charge time.
20200304/https://en.wikipedia.org/wiki/Power-on_reset
Is there a reliable power-on RESET signal on Raspberry Pi? Well, looks like it could be that pretty much all GPIO pins on Raspberry Pi function as power-on RESET signals, so there you have it.
20200304/DuckDuckGo raspberry pi power on reset
20200304/https://raspberrypi.stackexchange.com/questions/1032/what-is-the-power-on-state-of-the-gpios
UPDATE 2020-10-25: Please see my newer article for corrections about the RESET GPIO pin behavior.
Also, in the process of searching for this, I found that Raspberry Pi also has a built-in watchdog timer. Wow, now that’s very nice.
20200304/https://raspberrypi.stackexchange.com/questions/1401/how-do-i-hard-reset-a-raspberry-pi#1403