the iWatch processor … any guesses?
We are only a few days away from Apple’s Spring Forward event. Despite the reference to the switch to daylight savings time pretty much everyone is expecting further details about and possible launch date for the iWatch.
I too think these latter agenda items have pretty good odds. Since its announcement last fall there have been ongoing rumours around the iWatch’s battery life. In particular there has generally been consensus around the need for a daily charge. At the moment I do not want to weigh in on this number. I do though want to think about some of the factors contributing to battery life.
To me, the iWatch looked to be on the thick side. That said there is quite a bit to pack in there. One can start at the backside with the various sensors and charging hardware, to the battery pack, the printed circuit board and ICs thereon, and the display. From here one can back out that the battery is likely quite thin i.e. has a small capacity. Within the ICs there would have to be basic logic (i.e. CPU) to control everything, graphics for the display, non-volatile and random access memory and Input/Output (I/O) for sensor data. This is a big list. It is not a stretch to guess that power management within these circuits/ICs will be paramount.
I do not think there is much doubt that Apple will have designed the main chip i.e. the Applications Processing Unit or APU. I would not anticipate anything near as monstrous as the A8X. Rather the IC will likely be stripped down for this particular application. It is also likely that power management considerations were central in the design process. Often power management pushes one to get as much on one IC as possible. From my armchair I am curious about just how much is integrated onto the APU. Did they go for a funky process that can integrate all the required memory, and its control, onto one die? Apple is often not too adventurous on the first pass. That said their semiconductor design unit has certainly shown some pedigree in the A-series family and the iWatch APU may be something to watch (no pun intended).