https://uomosul.edu.iq/engineering/%d8%a8%d9%88%d8%b1%d8%af-ppi-programmable-peripheral-interface%d9%81%d9%8a-%d9%85%d8%ae%d8%aa%d8%a8%d8%b1-%d8%a7%d9%84%d9%83%d8%aa%d8%b1%d9%88%d9%86%d9%8a%d9%83-%d9%81%d9%8a-%d9%82%d8%b3%d9%85/