Embedded Lab

Designed by Nick, a BSEE student at Oakland University, ChronosMega is an Atmega328-based wrist watch that is battery-powered (3.7V rechargeable Li-Ion) and displays time (hours and minutes) in binary format using 10 LEDs. The LEDs  are arranged in a special circular pattern, where the four LEDs in upper half circle displays hours and the remaining six LEDs in the lower half circle display minute. The watch also contains an USB charger onboard, which uses Microchip’s MCP73831 charge management controller IC. There are four tact switches for user interface that controls the time setting, display, and sleep mode operation. Time keeping is performed using the 8-bit Timer2 module of Atmega328, which is programmed to count 10th of a second asynchronously from the system. For precise Timer2 operation, a 32.768 kHz crystal is used for the XTAL pins of Atmega328.