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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 ser-
     viced sufficiently	quickly	to prevent the 12 byte receive FIFO on a se-
     rial channel from overflowing.  Reducing the value	of the
     RX_FIFO_THRESHOLD #define from 6 to something smaller may help slow ma-
     chines 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
     <gemini@geminix.in-berlin.de> and the high-performance com	driver by
     Bruce Evans <bde@kralizec.zeta.org.au>.

     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 <andrew@werple.apana.org.au>.

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	13.0			 July 23, 2020			  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | DIAGNOSTICS | SEE ALSO | HISTORY | AUTHORS | BUGS

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