Copyright (c) 1997 The NetBSD Foundation, Inc.
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This code is derived from software contributed to The NetBSD Foundation
by Gordon W. Ross.
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.Dd October 23, 1997 .Dt ZSTTY 4 .Os .Sh NAME .Nm zstty .Nd serial communications interface .Sh SYNOPSIS .Cd "zstty* at zs0" Pq sparc .Cd "zstty* at zsc1" Pq others .Sh DESCRIPTION The .Nm driver provides TTY support for Zilog 8530 Dual UARTS.
p Input and output for each line may set to any baud rate in the range 50 to 38400 (and higher on some machines). .Sh FILES l -tag -width Pa t Pa /dev/ttya t Pa /dev/ttyb .El .Sh DIAGNOSTICS l -tag -width indent -compact t zs0*: fifo overflow The on-chip .Dq fifo has overflowed and incoming data has been lost. This generally means the machine is not responding to interrupts from the ZS chip fast enough, which can be remedied only by using a lower baud rate. t zs0*: ring overflow The software input .Dq ring has overflowed. This usually means input flow-control is not configured correctly (i.e. incorrect cable wiring). .El .Sh SEE ALSO .Xr scc 4 .Xr tty 4 .Sh HISTORY The .Nm driver was derived from the .Nm sparc .Nm zs driver supplied with x 4.4 . d .Sh BUGS The old Zilog 8530 chip has a very small fifo (3 bytes?) and therefore has very strict latency requirements for the interrupt service routine. This limits the usable baud rates on many machines.
Indexes created Tue Oct 21 19:09:51 GMT 2025