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ATRTC(4FREEBSD) - Linux man page online | Special files

AT Real-Time Clock (RTC) driver.

Chapter
September 17, 2010
ATRTC(4) BSD Kernel Interfaces Manual ATRTC(4)

NAME

atrtc — AT Real-Time Clock (RTC) driver

SYNOPSIS

This driver is a mandatory part of i386/amd64 kernels. The following tunable is settable from the loader(8): hint.atrtc.X.clock controls event timers functionality support. Setting to 0, disables it. Default value is 1.

DESCRIPTION

This driver uses RTC hardware to supply kernel with time-of-day clock with 1 second resolu‐ tion and one event timer. This hardware uses base frequency of 32768Hz for advancing time- of-day clock and generating periodic interrupts. Interrupts could be generated with fixed number of frequencies, from 2Hz to 8192Hz, obtained by dividing base frequency by one of supported power-of-2 divisors. Event timer provided by the driver is irrelevant to CPU power states.

SEE ALSO

apic(4), attimer(4), eventtimers(4), hpet(4)
BSD September 17, 2010 BSD
This manual Reference Other manuals
atrtc(4freebsd) referred by acpi_hpet(4freebsd) | apic(4freebsd) | attimer(4freebsd) | eventtimers(4freebsd) | hpet(4freebsd) | i8254(4freebsd)
refer to apic(4freebsd) | attimer(4freebsd) | eventtimers(4freebsd) | hpet(4freebsd)
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