Concurrent Technologies RCIM, Руководство пользователя

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Chapter 1
Functional Description
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This chapter describes the clocks and interrupt capabilities provided by the RCIM and the
user interfaces for each.
Overview
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The Real-Time Clock and Interrupt Module (RCIM) provides two non-interrupting clocks.
One of these clocks can be synchronized with all the RCIMs in an RCIM chain to provide
a common time stamp across systems. The other clock is POSIX 1003.1 compliant and,
although not synchronized across the RCIM chain, it increments in unison with the other
clock on the RCIM board and can be set to a specific time.
In addition to the clocks, the following methods for handling signal processing (interrupts)
are available:
•
Edge-Triggered Interrupts (ETIs)
•
Real-Time Clocks (RTCs)
•
External Output Interrupts
•
Programmable Interrupt Generators (PIGs)
•
Distributed Interrupts (DIs)
These interrupts operate locally on an RCIM system or can be distributed across all RCIM
systems in an RCIM chain. The
open(2)
,
close(2)
and
ioctl(2)
system calls are
used to manipulate the interrupts. Separate device files are associated with each interrupt.
The clocks and interrupts are described in this chapter.
Clocks
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The RCIM provides two non-interrupting clocks, which are fully explained in the sections
that follow.
tick a 64-bit non-interrupting clock that increments by one on each
tick of the common 400ns clock signal. This clock can be reset to
zero and synchronized across the RCIM chain, providing a
common time stamp.
POSIX a 64-bit non-interrupting clock encoded in POSIX 1003.1 format.
The upper 32 bits contain seconds and the lower 32 bits contain
nanoseconds. This clock is incremented on each tick of the
common clock signal. It is primarily used as a high-resolution
local clock. It can be configured to synchronize system time with
GPS standard time on boards equipped with GPS.
All clocks on all RCIMs in the chain are incremented in unison, as they are all driven by a
common clock signal emanating from the master RCIM.