Reporter on a Raspberry Pi 5 couldn't read NFC tags — gauge worked,
SPI bus and wiring fine, but PN5180 transfers didn't complete.
Manually commenting out `self._spi.no_cs = True` restored
communication. Root cause: Pi 5's RP1 southbridge SPI driver
(spi-rp1) doesn't honour the SPI_NO_CS ioctl the way the historical
Broadcom driver on Pi 4 did.
Safe to relax Pi-wide. SpoolBuddy's PN5180 NSS line is wired to
GPIO23 (manual CS in _cs_low / _cs_high — the kernel's default
auto-CS timing doesn't meet the PN5180's 5µs setup / 100µs hold
spec). The hardware CE0 line (GPIO8) is not connected to the
reader, so whether the kernel auto-toggles it is electrically
invisible. The no_cs = True call was always cosmetic on this
hardware.
Wraps the assignment in try/except OSError in both the daemon and
the diagnostic script; the daemon logs at debug level so future
Pi-5-specific triage is greppable. README updated to drop the
"spidev.no_cs = True resolves this" sentence and explain the
manual GPIO23 CS scheme carries the timing on its own.
NTAG 213/215/216 chips can report SAK 0x04 (MIFARE Ultralight family)
instead of 0x00 during anticollision. Accept both values for NTAG
detection and write operations in nfc_reader.py and main.py.
maziggy