===== Clock around the GPIOs ===== No need for an external crystal, one can use the GPIOs of the Raspberry Pi to generate a clock signal. The library wiring makes it easy and accessible.\\ \\ [[http://wiringpi.com/|Wiring]] for the Raspberry Pi was written by Gordon Henderson.\\ ==== Install Wiring ==== In the terminal: $ sudo apt-get install wiringpi For the Raspberry Pi 4 one needs to update the WiringPi to version 2.52: $ cd /tmp $ wget https://project-downloads.drogon.net/wiringpi-latest.deb $ sudo dpkg -i wiringpi-latest.deb [[http://wiringpi.com/wiringpi-updated-to-2-52-for-the-raspberry-pi-4b/]]\\ ---- ==== Clock the Pin ==== The clock frequency is derived from the 19.2MHz Raspberry Pi clock. One can use GPIO 4 (pin7), GPIO 5 and GPIO 6.\\ 2.4Mhz would be 2400000\\ Terminal example:\\ $ gpio mode 7 clock $ gpio clock 7 2400000 Or in C:\\ pinMode (pin, GPIO_CLOCK) ; gpioClockSet (pin, frequency) ; ---- ==== GPIOs ====

graphic by [[https://indibit.de/raspberry-pi-die-gpio-schnittstelle-grundlagenbelegung/|indiBit.de]]\\ License: CC BY-NC-SA 3.0 DE\\ ---- ==== Links ==== [[http://wiringpi.com/]]\\ [[https://www.raspberrypi.org/forums/viewtopic.php?t=22274]]\\ ----