A block diagram of the BCM2835 does not exist; however, based on the information available about this IC I have drawn one. The Broadcom BCM2835 is a System on Chip (SoC) with multimedia capabilities, and usually utilised in mobile phones and portable devices. It is a highly competitive industry and nearly all the big names that manufacture SoC chips keep their designs a secret.
You have probably looked at the Broadcom BCM2835 datasheet and realised that it lacks the processor architecture diagram, and even the basic block diagram showing what is inside the processor. This is vital information for electronic engineers who work at hardware level; however, it will be some time before it becomes available to the public.
This IC provides a full HD video and stereo audio. You would expect to find it in digital camcorders, digital cameras, mobile phones, games boxes, and the applications are limitless. It has a VideoCore IV® Multimedia Co-Processor, ARM1176JZ-F application processor, and high performance OpenGL-ES® 1.1/2.0 GPU.
It is interesting to note that this chip also has an advanced Image Sensor Pipeline (ISP) for connecting a 20 MP Camera. It can transfer data at the rate of 220 MP/s. There is also an LCD MIPI type interface for driving a high-resolution LCD panel at 1080p resolutions.
As you can see from the block diagram, a system on chip has everything usually found at motherboard level, and therefore they are the most easiest to implement. Usually an IC such as this requires just a power supply and some sockets for connecting the peripherals.