jamesh wrote:To expand on the point in my previous post, do you need all four cores runnings? Will you be using the camera? Will you be using the 3D block? Will you be using the H264 decoder or encoder?
Hmm. I'm not sure if these questions are serious (I use two cameras, encoded to mjpeg, no display whatsoever, so my core requirements are actually low), or if you're just trying to show me that this is a complex issue. I do realize that this isn't simple. But please let me show an example of how NXP gets this right.
Let's look at the datasheet for the KL03Z microcontroller, available at http://cache.freescale.com/files/32bit/ ... M48SF0.pdf
— Section 2.2.5 on page 10 lists the "KL03 QFN packages power consumption operating behaviors" — you get typical and max currents for all power modes for the main core. This is followed by the WLCSP package, and then by what they call "peripheral adders", meaning how much current you need to add if you are using a particular peripheral. These tables let me quickly estimate the power requirements for my particular use case, with fairly good precision.
I do realize that the BCM283x is a vastly more complex chip, and the CM adds more complexity on top, but it is entirely possible to create a similar table listing the core(s) power requirements, and peripheral adders.
jamesh wrote:Every one of those affects the power requirements of the device. And in fact, the only difference between CM1 and CM3 in all those respects is the ARM cores requirements. Everything else is the same.
…and this is actually a very useful bit of information, that I did not have until now!