CY(4) FreeBSD Kernel Interfaces Manual CY(4)
NAME
cy - Cyclades Cyclom-{4, 8, 16}Y asynchronous comms board device driver
SYNOPSIS
cy0 at isa? iomem 0xd4000 irq 12
cy* at pci?
DESCRIPTION
This driver provides an interface to Cyclades Cyclom-4Y, Cyclom-8Y and
Cyclom-16Y asynchronous multiport serial boards. These boards are based
around Cirrus Logic CD1400 communication controllers.
The device minor numbers for this driver are encoded as follows:
d c c u u u u u - bits in the minor device number
bits meaning
---- -------
uuuuu physical serial line (i.e., unit) to use
0-7 on a cyclom-8Y, 0-15 on a cyclom-16Y
cc card number
d dial-out flag
DIAGNOSTICS
cy0: port 0 ibuf overrun Incoming characters have been discarded due to
a buffer overflow.
cy0: port 0 fifo overrun Incoming characters have been discarded due to
a CD1400 channel overrun. This is caused by interrupts not being
serviced sufficiently quickly to prevent the 12 byte receive FIFO on a
serial channel from overflowing. Reducing the value of the
RX_FIFO_THRESHOLD #define from 6 to something smaller may help slow
machines avoid this problem.
SEE ALSO
com(4), intro(4), isa(4), pci(4), termios(4), tty(4)
HISTORY
Some ideas for the architecture of this driver's two-layer processing
model were derived from the fas 2.10 driver by Uwe Doering
<
[email protected]> and the high-performance com driver by
Bruce Evans <
[email protected]>.
This work was made possible through the donation of a Cyclom-8Y board by
the manufacturer, Cyclades Corporation. However, neither Cyclades nor
the author make any warranties regarding this software, nor guarantees of
support.
AUTHORS
The driver was written by Andrew Herbert <
[email protected]>.
BUGS
There is currently no BREAK handling - breaks are ignored. There is no
support for bad-character reporting, except via PARMRK. The Cyclom-[48]Y
boards do not listen to the RTS signal for receiver flow control. FIFO
overruns are only logged when the termios IGNPAR setting is enabled.
FreeBSD 14.1-RELEASE-p8 July 23, 2020 FreeBSD 14.1-RELEASE-p8