pureboot.py (Python stdlib only): images as raw binary or Intel HEX,
flash and EEPROM programming with read-back verify, erase composites,
fuse and info readout, activation-timeout configuration, and the
tinies' reset-vector surgery — the trampoline word below the loader,
page 0 written last.
The test spawns a simavr device (pureboot_device.c) — the mega's USART
as a pty; on the tinies a cycle-timed GPIO<->pty bridge for the polled
software UART plus the NVM module simavr's tiny cores lack (their SPM
opcode ioctls into a void and silently does nothing) — and drives it
with the real tool: knock from reset (erased-flash walk on the tinies),
program and verify both memories, timeout write, session reconnect, an
external reset through the patched vector, hand-over, and the fixture
application's banner. Results are cross-checked against ground-truth
memory dumps and an independent decode of the surgery's rjmp words,
red-verified against a sabotaged encoder.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
No inline assembly, no global register variables; libavr does the
datasheet work. The device speaks primitives — flash read/page-program,
EEPROM read/write, fuse read, info block, EEPROM-resident activation
timeout, hand-over — and verify, erase, reset-vector surgery, and
timeout configuration live in the host tool. 490 B on the ATtiny13A,
510 B on the ATtiny85, 484 B on the ATmega328P, each linked into the
top 512 bytes of flash; per-chip size tests gate all three.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
