NetBSD/share/man/man4/man4.pmax/scc.4

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.\" Copyright (c) 1996 Jonathan Stone.
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.\" $Id: scc.4,v 1.1 1996/08/11 02:29:19 jonathan Exp $
.\"
.Dd August 6, 1996
.Dt SCC 4 pmax
.Os NetBSD 1.2
.Sh NAME
.Nm scc
.Nd
Zilog serial communications interface
.Sh SYNOPSIS
.Cd "scc0 at ioasic?"
.Cd "scc1 at ioasic?"
.Sh DESCRIPTION
THe
.Nm
driver provies support for the Zilog 8530 Serial Communcations
Controller (SCC) via the IOCTL asic on DECstation 5000 models
in the /100, /20, and /240 series. Each scc device has two serial
ports. The model 20 provides one scc device. Other models provide two,
but one port of each device is dedicated to mouse and keyboard input,
respectivey.
.Pp
Input and output for each line may set to one of following baud rates;
50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600,
19200, 38400, or 57600.
Speeds up to 230400 are supported by the chip and the motherboard,
but speeds higher than 57600 do not work reliably without an external
clock signal.
.Sh HISTORY
The
.Nm
driver first appeared in
.Bx 4.4 .
.Sh BUGS
The IOCTL asic provides internal DMA channels that can be programmed
to transfer up to 4096 bytes of data into, or out, of an SCC without
further software intervention. This feature of the ioctl asic is not
yet supported.