Abstract: This application note provides example hardware and software for interfacing the DS3231 with an 8051-type microcontroller. Figure 1. DS3231 Pin assignment. Description This application note demonstrates how to interface a DS3231 to an 8051-type microcontroller and provides example code showing basic interface routines. The microcontroller used in this example is the DS2250, and the software is written in C. Operation The program uses two general-purpose port pins on the microcontroller to operate as a master on the I²C* bus. The DS3231 operates as a slave device on the same bus. The program demonstrates setting and reading the time and date, as well as reading and displaying temperature data. The program displays the time, date, and temperature information on an LCD display, which utilizes a standard HD44780 controller. Pin assignment and a schematic of the DS3231 are shown in Figures 1 and 2, respectively. The software is shown in Figure 3. For Larger Image Figure 2. Schematic of the DS3231. Download text file Figure 3. Example Software We Want Your Feedback! Automatic Updates Would you like to be automatically notified when new application notes are published in your areas of interest? Sign up for EE-Mail™. More Information   APP 3506: May 23, 2005 DS3231 Extremely Accurate I²C-Integrated RTC/TCXO/Crystal Full Data Sheet (PDF, 368kB) Free Samples DS3232 Extremely Accurate I²C RTC with Integrated Crystal and SRAM Full Data Sheet (PDF, 284kB) Free Samples   Download, PDF Format (34kB)  AN3506, AN 3506, APP3506, Appnote3506, Appnote 3506