May 26, 2009

Designing devices with time

Currently there are many embedded devices that needs some sort of time settings. This is a brief description of what to remember when designing systems that depend on time.

Firstly, the device time chip should be checked for backup and recovery. Figure out how to use this for backing up the time!! This is important as the time becomes an issue when synchronizing data between devices like the embedded one and the PC.

Consider the following:
1. Initial time in the device, how is the time written to the time chip the first time? How can the device know the difference between first "real" boot and all other boot's.

2. How is the time synchronized between the systems?? What format is used for communication?? How is data marked as valid or invalid. Transmitted or not transmitted.

3. Is the implementation on both sides using the same interpretation of the "time.h" standard (if this is the chosen time format) and can they both handle the summer time setting?