A bunch of accelerometers on the market today have a FIFO. Why is the XL362 FIFO better?
A FIFO has similar functionality to your DVR at home. It can record data (TV shows) while you’re not watching, and then give you the data faster (or, let you watch your shows without commercials) on your own schedule. In the same way that a DVR records shows while you might be sleeping, a FIFO records data while the host processor is sleeping, or tending to other tasks. Having a deeper FIFO is like having a DVR with more memory: the host processor can sleep longer and save more power. A DVR also lets you rewind live TV (if, for example, you were looking away), because it always has a buffer filled with some amount of previous data. The bigger your DVR memory, the further back you can rewind TV, and the longer you can look away without missing the action. Now wouldn’t it be neat if your DVR could tell you when something interesting happened on TV, told you to come watch, and then let you rewind so you could watch? This is what the ADXL362 does: motion processing sends an interrupt when a motion event occurs, and the FIFO allows you to see what was going on before that trigger. The more memory in your DVR (or the deeper your FIFO), the more of your show you can see (or, the more data you can access), to find out what led up to the interesting event.