Real Time Clock (RTC) is used to store Time and Date in the system even when the system is not in operation. This is the system used in many devices including Laptop. Mobile phones, Tablet, Digital Cameras etc. RTC is inbuilt part of any electronics device. DS1307 is widely used RTC which we can interface with any controller. Many controllers now has inbuilt RTC to store timing information. In this article, we will learn how to configure inbuilt RTC of controller LPC 2148.