Architecture specification
Beginner
The document that sketches how the chip will be built: which big blocks it has and how they connect.
Novice
The document that describes the chip as a set of large blocks (processors, memories, accelerators, connections to the outside) and how they talk to each other. It answers, block by block, how the chip will meet its requirements.
Expert
Owned by the chip architects. It fixes how the chip is split into blocks, the interfaces between them, the memory map (which addresses reach which block), the clock and power domains (regions that run at their own speed or can be switched off), and the power, area and performance budget each block gets. The block-level microarchitecture specs are written from it.