On an ATTINY416 NANO dev board:
The fuses APPEND and BOOTEND are both 0x00 (as seen in the "Device Programming" tool in Atmel Studio 7). According to the full datasheet, this means that the entire flash is boot section, which seems unfeasible to me - I don't know now the chip can run with no APP CODE. I have been using the board for dev for several weeks, and never noticed the fuses 'til now, because now I need to reserve a minimal space for APP DATA. Setting APPEND requires knowing how big BOOT really is. I did not alter any fuses on this board, and after programming the chip, it runs at power-up. Are these the factory default values for BOOTEND and APPEND? Of course it is possible that the tool is busted and is misreading the fuses 8(.
The description for BOOTEND in the data sheet is unhelpful, owing to the obvious error (unless "whole Flash" and "entire Flash" mean different things):
Bits 7:0 – BOOTEND[7:0]: Boot Section End
These bits set the end of the boot section in blocks of 256 bytes. A value of 0x00 defines the whole Flash
as BOOT section. When both FUSE.APPEND and FUSE.BOOTEND are 0x00, the entire Flash is BOOT
Surely, if BOOTEND == 0x00, then BOOT must be some default size (?).
Does anyone know how to learn the actual size of BOOT, so that I can set the BOOTEND fuse, so that I can set the APPEND fuse?
As always, all commentary is gratefully received.