Copyright (c) 2004 Jason L. Wright (jason@thought.net)
Copyright (c) 2005 Marius Strobl <marius@FreeBSD.org>
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from: OpenBSD: clock.4,v 1.3 2004/09/24 07:04:15 miod Exp
$FreeBSD: releng/11.0/share/man/man4/man4.sparc64/rtc.4 267938 2014-06-26 21:46:14Z bapt $
.Dd June 18, 2005 .Dt RTC 4 sparc64 .Os .Sh NAME .Nm rtc .Nd "non-volatile RAM / real time clock" .Sh SYNOPSIS .Cd "device genclock" .Cd "device mc146818" .Cd "device rtc" .Sh DESCRIPTION The .Nm driver is a front-end for the machine-independent .Tn Motorola MC146818 and compatible clocks driver. The .Tn Motorola MC146818 and compatible clocks driver provides access to the real time clock part of the chips it supports to .Fx by interfacing with the generic clock code.
p .Tn Dallas / .Tn Maxim Semiconductor DS1287 chips (those are compatible to the .Tn Motorola MC146818 clocks) are found on the ISA bus of .Tn UltraSPARC II systems and the EBus bus of .Tn UltraSPARC III systems. .Sh DIAGNOSTICS The following driver specific error message may be reported: l -diag t "mc146818_attach_attach: battery low" The device signals that its battery is low and should be replaced. The .Nm driver refused to attach the device in this case as the time in the real time clock is probably invalid. This gives the generic clock code the chance to use another device as the system real time clock that otherwise would not have been chosen. .El .Sh SEE ALSO .Xr ebus 4 , .Xr eeprom 4 .Sh HISTORY The .Nm driver first appeared in .Fx 5.4 . .Sh AUTHORS The .Nm driver was written by .An Marius Strobl Aq Mt marius@FreeBSD.org .