It’s a specialised processor, but also a powerful processor and most people would like to run code on it, just like we’re running code on the GPU itself, but alas the GPU information is still under NDA (Non-Disclosure Agreement) terms.
Broadcom however, did release some information and some of the most interesting information is in the [ (BCM21553 Graphics Driver).
I’ll reference what material I’ve got from there as we go.
Unfortunately there is no definitive source of information for the Raspberry Pi GPU, only bits and pieces scattered around the web. As we’re going to use the mailbox communication with the GPU anyway, we can skip a lot of the GPU detail and just concentrate on communicating with the GPU to get a framebuffer to use.
The interface was developed and created by a few guys at broadcom.
In this way we can see the raw speed of the processor at work. We’ll optimise in the ARM015 code later on in this tutorial.
Read that title carefully, not getting a graphics Text Console but instead getting some text out of the code to help us debug.
So we have access to each pixel on the screen and can change it’s colour properties.
The framebuffer should be at least as big as the screen resolution.