6.3 In-System Reprogrammable Flash Program Memory

The ATtiny1617/3217 contains 32/16 KB on-chip in-system reprogrammable Flash memory for program storage. Since all AVR instructions are 16 or 32 bits wide, the Flash is organized as 4K x 16. For write protection, the Flash program memory space can be divided into three sections (see the illustration below): Bootloader section, application code section, and application data section, with restricted access rights among them.

The Program Counter (PC) is 13/14 bits wide to address the whole program memory. The procedure for writing Flash memory is described in detail in the documentation of the Nonvolatile Memory Controller (NVMCTRL) peripheral.

The entire Flash memory is mapped in the memory space and is accessible with normal LD/ST instructions as well as the LPM instruction. For LD/ST instructions, the Flash is mapped from address 0x8000. For the LPM instruction, the Flash start address is 0x0000.

The ATtiny1617/3217 also has a CRC peripheral that is a master on the bus.