Eric Wild 88a6a782a2 firmware: use the full 11 bit US_FIDI.FI_DI_RATIO ...

US_FIDI_FI_DI_RATIO_Msk is 0x7ff,
cemu rejected >= 0x400 in emu_update_fidi() and masked with 0x3ff
in card_emu_uart_update_fidi(), but update_fidi() used by
the sniffer already used 0x7ff.

-> ratios 1024..2047 are unusable in cemu, which is the entire upper
half of ISO 7816-3 Table 7 at Di=1.

A reader trying one of those in a PPS gets the proposal echoed and
accepted, after which the card keeps transmitting at the old rate.

FI_DI_RATIO is clock periods per bit -> larger ratio is a SLOWER link.
The old check rejected slow values but accepted Fi=372/Di=64, ratio 5 !?

Unify and use the register mask (= shifed by 0 so usable as value) and
reject ratios that do not fit rather than truncating to garbage dividers.

Change-Id: I6211dd5be7c5c5d2150af2aa37a403b33e6d340d

2026-08-10 16:13:59 +00:00

..

include

firmware: card_emu.h: declare usb_buf_upd_len_and_submit()

2026-07-14 18:24:44 +02:00

source

firmware: use the full 11 bit US_FIDI.FI_DI_RATIO

2026-08-10 16:13:59 +00:00