xref: /openbsd/share/man/man4/cy.4 (revision cecf84d4)
1.\"	$OpenBSD: cy.4,v 1.16 2013/07/16 16:05:48 schwarze Exp $
2.\"
3.\" Copyright (c) 1993 Andrew Herbert.
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28.Dd $Mdocdate: July 16 2013 $
29.Dt CY 4
30.Os
31.Sh NAME
32.Nm cy
33.Nd Cyclades Cyclom-{4, 8, 16}Y asynchronous comms board device driver
34.Sh SYNOPSIS
35.Cd "cy0 at isa? iomem 0xd4000 irq 12"
36.Cd "cy* at pci?"
37.Sh DESCRIPTION
38This driver provides an interface to Cyclades Cyclom-4Y, Cyclom-8Y and
39Cyclom-16Y asynchronous multiport serial boards.
40These boards are based around Cirrus Logic CD1400 communication controllers.
41.Pp
42The device minor numbers for this driver are encoded as follows:
43.Bd -literal
44    d c c u u u u u	- bits in the minor device number
45
46    bits    meaning
47    ----    -------
48    uuuuu   physical serial line (i.e., unit) to use
49		0-7 on a cyclom-8Y, 0-15 on a cyclom-16Y
50
51    cc      card number
52
53    d       dial-out flag
54.Ed
55.Sh DIAGNOSTICS
56.Bl -diag
57.It "cy0: tty input queue overflow"
58Incoming characters have been discarded due to a buffer overflow.
59This is caused by the process in control of the device not
60.Xr read 2 Ns 'ing
61characters fast enough.
62.It "cy0: receive fifo overrun"
63Incoming characters have been discarded due to a CD1400 channel overrun.
64This is caused by interrupts not being serviced sufficiently quickly to prevent
65the 12 byte receive FIFO on a serial channel from overflowing.
66Reducing the value of the \fIRxFifoThreshold\fR #define from 8 to something
67smaller may help slow machines avoid this problem.
68The driver must have been compiled with the \fILogOverruns\fR option
69defined (the default) in order for this condition to be logged.
70.El
71.Sh SEE ALSO
72.Xr com 4 ,
73.Xr intro 4 ,
74.Xr isa 4 ,
75.Xr pci 4 ,
76.Xr termios 4 ,
77.Xr tty 4
78.Sh HISTORY
79Some ideas for the architecture of this driver's two-layer processing model
80were derived from the fas 2.10 driver by
81.An Uwe Doering Aq Mt gemini@geminix.in-berlin.de
82and the high-performance com driver by
83.An Bruce Evans Aq Mt bde@kralizec.zeta.org.au .
84.Pp
85This work was made possible through the donation of a Cyclom-8Y board by the
86manufacturer, Cyclades Corporation.
87However, neither Cyclades nor the author make any warranties regarding
88this software, nor guarantees of support.
89.Sh AUTHORS
90The driver was written by
91.An Andrew Herbert Aq Mt andrew@werple.apana.org.au .
92.Sh BUGS
93There is currently no BREAK handling - breaks are ignored.
94There is no support for bad-character reporting, except via PARMRK.
95The Cyclom-[48]Y boards do not listen to the RTS signal for receiver flow
96control.
97FIFO overruns are only logged when the termios IGNPAR setting is enabled.
98