 In devices with many peripherals, these registers are followed by 160 “extended I/O” registers, only accessible as memory-mapped I/O (006016–00FF16).Actual SRAM starts after these register sections, at address 006016 or, in devices with "extended I/O", at 010016.Even though there are separate addressing schemes and optimized opcodes for accessing the register file and the first 64 I/O registers, all can also be addressed and manipulated as if they were in SRAM.