Copyright (c) 1993 Andrew Herbert.
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$Id: cy.4,v 1.1 1993/10/06 09:45:31 andrew Exp $
.Dd 5 October, 1993 .Dt CY 4 i386 .Sh NAME .Nm cy .Nd Cyclades Cyclom-{4, 8, 16}Y asynchronous comms board device driver .Sh SYNOPSIS .Cd "device cy0 at isa? tty irq 10 iomem 0xdc000 iosiz 8192 vector cyintr" .Sh 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.
p The device minor numbers for this driver are encoded as follows:
p d -literal c c x x u u u u - bits in the minor device number bits meaning ---- ------- uuuu physical serial line (i.e. unit) to use 0-7 on a cyclom-8Y, 0-15 on a cyclom-16Y xx unused cc carrier control mode 00 complete hardware carrier control of the tty. DCD must be high for the open(2) to complete. 01 reserved 10 carrier ignored until a high->low transition 11 carrier completed ignored .Ed .Sh DIAGNOSTICS l -diag t "cy%d: tty input queue overflow" Incoming characters have been discarded due to a buffer overflow. This is caused by the process in control of the device not read(2)ing characters fast enough. t "cy%d: receive 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 RxFifoThreshold #define from 8 to something smaller may help slow machines avoid this problem. The driver must have been compiled with the LogOverruns option defined (the default) in order for this condition to be logged. .Sh SEE ALSO .Xr com 4 , .Xr termios 4 , .Xr tty 4 .Sh AUTHORS The driver was written by Andrew Herbert <andrew (at] werple.apana.org.au>, and is still under development (from time to time :-). .Sh 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 (at] geminix.in-berlin.de> and the high-performance com driver by Bruce Evans <bde (at] kralizec.zeta.org.au>.
p 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. .Sh 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.
Indexes created Sun Oct 19 22:09:57 GMT 2025