Quote from Seth G:
The chip at the upper right corner of the Snapdragon is an Atmel Mega88, microcontroller
. Spec sheet describes it as an 8-bit AVR RISC microcontroller w/ 8K programmable flash memory.
Seth - The Atmel chip is most likely used for the cap touch buttons along the bottom of the phone, and possibly for other touch features such as haptics, light sensors or other cap sense user interface features.
Of course I could only verify this if someone sends me one to play with ;)