Yeah, there's a lot of support for doing atmel/Arduino projects and nothing for even beginning to approach anything deeper.

Often times knowledge of firmware is also relevant (mostly in C). For example hooking up a memory to a microchip, which protocol do you choose, how big does it need to be, how fast can it read/write all depend on the specific application. That sort part selection requires knowing how you plan on using it in the firmware as well as how fast you intend on using it.

There will then be the nuts and bolts of what supporting hardware is needed, but every manufacturer will include implemention details for their chips. Reviewing the latest data sheets is a decent way to keep up on modern techniques too.