rpdom wrote: ↑
Sun Jan 21, 2018 8:46 am
mwrich4 wrote: ↑
Sun Jan 21, 2018 7:42 am
I think the thing to remember is this: while the raspberry pi processor chip uses familiar building blocks, the design and implementation were towards the goal of making a small minimalist hobbyist computer system in a tiny space. Trade-offs were made, functionality was not the prime goal. Reducing system cost and retaining decent user interface speeds was probably a detailed compromise.
The original Pi used an off-the-shelf chip that had also been used for Set Top boxes. There's not much reason for power saving modes in something that is going to be mains powered whenever it is in use.
BCM2835 was NOT designed for set top boxes. It was designed for mobile phones as a coprocessor, with the ARM core thrown in for experimentation.
It was used in one of the Roku streaming sticks, but set top boxes were not the intended market.
All the VideoCore blocks have numerous power saving techniques employed, however hooking them up to allow the ARM cores to really access them is non-trivial. Wherever the VideoCore processor (the VPU) is controlling a hardware block, then all the power and clock gating will be active.
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.