Re: TTL/USB converter usage question

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Mon, 14 Oct 2024 15:51:25 +0200
    From:        Ramiro Aceves <ea1abz%gmail.com@localhost>
    Message-ID:  <CANfMP74OHoueriUpR9U8g0PknWRRy+D+Mkc4f_hdvEC60LXP5A%mail.gmail.com@localhost>


  | netbsd-raspa4$ { sleep 1; stty -f /dev/ttyU0 ... ; } & cat /dev/ttyU0
  | stty: /dev/ttyU0: Resource temporarily unavailable

stty opens its -f arg file in O_NONBLOCK mode - that error (EAGAIN or
EWOULDBLOCK, they're the same thing) indicates that the open would
hang (the open in cat is probably hanging too).

This might be a case where dedicated C code is needed, or it may be that
the device isn't connected to anything in a way that the driver
considers as acceptable.

kre