Concurrent Technologies RCIM User manual

Real-Time Clock and Interrupt Module (RCIM)
Userís Guide
0898007-1000
March 2021

Copyright 2021 by Concurrent Real-Time. All rights reserved. This publication or any part thereof is intended for use
with Concurrent Real-Time products by Concurrent Real-Time personnel, customers, and end–users. It may not be
reproduced in any form without the written permission of the publisher.
The information contained in this document is believed to be correct at the time of publication. It is subject to change
without notice. Concurrent Real-Time makes no warranties, expressed or implied, concerning the information con-
tained in this document.
To report an error or comment on a specific portion of the manual, photocopy the page in question and mark the
correction or comment on the copy. Mail the copy (and any additional comments) to Concurrent Real-Time, 800 NW
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This publication may not be reproduced for any other reason in any form without written permission of the publisher.
Concurrent Real-Time and its logo are registered trademarks of Concurrent Real-Time. All other Concurrent Real-
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registered trademarks of their respective owners. Linux® is used pursuant to a sublicense from the Linux Mark
Institute.
Printed in U. S. A.
Revision History: Level: Effective With:
Original Release -- August 2002 000 RedHawk Linux Release 1.1
Previous Release -- December 2003 210 RedHawk Linux Release 2.0
Current Release -- May 2005 300 RedHawk Linux Release 2.3
Update -- September 2005 310 RedHawk Linux Release 2.3-4.1
Update -- May 2007 320 RedHawk Linux Release 4.2
Update -- April 2008 330 RedHawk Linux Release 5.1
Update -- June 2008 400 RedHawk Linux Release 5.1
Update -- October 2010 500 RedHawk Linux Release 5.4
Update -- December 2011 600 RedHawk Linux Release 6.0
Update -- February 2013 610 RedHawk Linux Release 6.3
Update -- February 2014 620 RedHawk Linux Release 6.3
Update -- March 2016 700 RedHawk Linux Release 7.2
Update -- June 2016 800 RedHawk Linux Release 7.2
Update -- June 2017 900 RedHawk Linux Release 7.3
Update -- March 2021 1000 RedHawk Linux Release 8.2

iii
Preface
Scope of Manual
This manual is intended for users responsible for the installation and use of the Real-Time
Clock and Interrupt Module (RCIM) on Concurrent Real-Time’s iHawkTM systems under
the RedHawkTM Linux® operating system.
NOTE
Two RCIM models are described in this guide: RCIM III and
RCIM IV. The use of the term “RCIM” refers to functionality
common to both boards. “RCIM III” and “RCIM IV” refer to the
specific boards. Refer to the section “Specifications” on page 1-3
for specifications for each of the boards.
NOTE
Both the RCIM III and RCIM IV are PCI Express boards. For
information covering the older RCIM I (PCI) and RCIM II (PCI-
X) boards, refer to the Legacy RCIM User’s Guide which can be
found in Concurrent’s Documentation Library at this location:
https://redhawk.concurrent-rt.com/docs/
Structure of Manual
This manual consists of the following:
•Chapter 1, Introduction, contains a general overview and specifications for
the RCIM boards.
•Chapter 2, Hardware, Installation and Configuration, provides a
description of the RCIM boards and connectors, as well as installation and
configuration instructions.
•Chapter 3, Functional Description, provides the general operation, user
interfaces and configuration options for the clocks and interrupts available
on the RCIM.
•Appendix A, RCIM IV Registers, describes the RCIM IV registers.
•Appendix B, RCIM III Registers, describes the RCIM III registers.
•Appendix C, Calculating RCIM Cable Propagation Delays, provides a
formula for guarding against propagation delay when chaining RCIMs.

RCIM User’s Guide
iv
Syntax Notation
The following notation is used throughout this guide:
italic Books, reference cards, and items that the user must specify appear in
italic type. Special terms may also appear in italic.
list bold User input appears in list bold type and must be entered exactly
as shown. Names of directories, files, commands, options and man
page references also appear in list bold type.
list Operating system and program output such as prompts, messages and
listings of files and programs appears in list type.
[] Brackets enclose command options and arguments that are optional.
You do not type the brackets if you choose to specify these options or
arguments.
hypertext links When viewing this document online, clicking on chapter, section,
figure, table and page number references will display the
corresponding text. Clicking on Internet URLs provided in blue type
will launch your web browser and display the web site. Clicking on
publication names and numbers in red type will display the
corresponding manual PDF, if accessible.
Related Publications
Title Pub No.
RedHawk Linux Release Notes Version x.x 0898003
RedHawk Linux User’s Guide 0898004
RedHawk Linux Frequency-Based Scheduler (FBS) User’s Guide 0898005
where x.x = release version

v
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Chapter 1 Introduction
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Chapter 2 Hardware, Installation and Configuration
Board Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
RCIM IV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Board Illustration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Connectors and LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
LED Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Input and Output Cables and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
GPS Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
External Interrupt I/O Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
System Identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Daisy Chain Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
RCIM III. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Board Illustration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Connectors and LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
LED Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Input and Output Cables and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
GPS Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
External Interrupt I/O Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
System Identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Daisy Chain Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Connection Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Unpacking the RCIM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Kernel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Driver Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
MSI Interrupt Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
System Timekeeping Configuration for GPS Support . . . . . . . . . . . . . . . . . . . . 2-19
Verifying GPS Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
Chapter 3 Functional Description
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
The Tick Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
The POSIX Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

vi
RCIM User’s Guide
Direct Access to the Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Synchronizing the Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
The rcim_clocksync Utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Synchronizing the Tick Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
RCIM Masterclock Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Synchronizing the POSIX Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Automatic Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Using GPS for System Timekeeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Interrupt Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Interrupt Processing Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Arming and Enabling DIs and ETIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Interrupt Recognition Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Setting up Distributed Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Obtaining RCIM Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Edge-Triggered Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Input Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
ETI Device Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
User Interface to ETIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
Distributed ETIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Real-Time Clocks (RTCs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
RTC Device Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Distributed RTCs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
User Interface to RTCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
External Output Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Output Source Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
Programmable Interrupt Generators (PIGs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
PIG Device File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Distributed PIGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Distributed Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
DI Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
DI Device Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
User Interface to DIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
RCIM IV Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Appendix A RCIM IV Registers
RCIM IV Address Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
RCIM IV Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5
Appendix B RCIM III Registers
RCIM III Address Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
RCIM III Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4
Appendix C Calculating RCIM Cable Propagation Delays
Interconnect Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

1-1
1
Chapter 1Introduction
1
This chapter provides an overview and specifications for the Real-Time Clock and
Interrupt Module (RCIM).
NOTE
Two RCIM models are described in this guide: RCIM III and
RCIM IV. The use of the term “RCIM” refers to functionality
common to both boards. “RCIM III” and “RCIM IV” refer to the
specific boards. The section “Specifications” provides specifica-
tions for each of the boards.
NOTE
Both the RCIM III and RCIM IV are PCI Express boards. For
information covering the older RCIM I (PCI) and RCIM II (PCI-
X) boards, refer to the Legacy RCIM User’s Guide which can be
found in Concurrent’s Documentation Library at this location:
https://redhawk.concurrent-rt.com/docs/
Overview 1
The Real-Time Clock and Interrupt Module (RCIM) is a PCI-based card that supports
time-critical applications that require rapid response to external events, synchronized
clocks and/or synchronized interrupts.
When RCIM boards of various systems are chained together, an interrupt can be
simultaneously distributed to all connected RCIMs, and from the RCIMs to all the
associated host systems.
A synchronized high-resolution clock is provided so that all the RCIMs in an RCIM chain
on multiple systems can share a common time base. It also provides a local POSIX 1003.1
compliant high resolution clock. An optional GPS module allows alignment of the clock
to GPS standard time. Multiple RCIMs equipped with the GPS module can provide a
common time base without cable connections. A high stability oscillator is standard.
Optional oscillators improve the accuracy of times measured with the RCIM.
In addition to the clocks, this multi-purpose PCI-based card has the following
functionality:
•connection of external device interrupts
•real-time clock timers that can interrupt the system

RCIM User’s Guide
1-2
•programmable interrupt generators which allow generation of an interrupt
from an application program
These functions can all generate local interrupts on the system where the RCIM card is
installed. When systems are chained together, multiple input and output interrupts can be
distributed to other RCIM-connected systems. This allows one timer or one external
interrupt or one application program to interrupt multiple RedHawk Linux systems almost
simultaneously to create synchronized actions.

Introduction
1-3
Specifications 1
Feature RCIM IV RCIM III
Clocks
POSIX
Length 64 bits (two 32-bit words) 64 bits (two 32-bit words)
Resolution High-order 32 bits–1 second
Low-order 32 bits–400 nsec
High-order 32 bits–1 second
Low-order 32 bits–400 nsec
Oscillator stability +/-1.0 PPM +/-2.5 PPM
Tick Timer
Length 64 bits (two 32-bit words) 64 bits (two 32-bit words)
Resolution 64 bit counter of 400 ns ticks 64 bit counter of 400 ns ticks
Real-Time Clocks
Number 8 8
Length 32 bits 32 bits
Resolution 1 microsecond
(larger values programmable)
1 microsecond
(larger values programmable)
Oscillator stability +/-1.0 PPM +/-2.5 PPM
Local Interrupts
External Input Interrupts 12 shared inputs and/or outputs
(3.5V or 5V TTL)
12 (5V TTL)
External Output Interrupts 12 (5V TTL)
Real-Time Clocks 8 8
Distributed Interrupts
Input 12 12
Output 12 12
Interrupt Response Time
Interrupt to user process < 8 microseconds < 8 microseconds
Packaging
Form Factor PCIe PCIe
Maximum cable length
(See Appendix C for calculations.)
30 meters 30 meters
External Connectors 26-pin HD D-SUB Molex LFH-60
PCI Performance x1 x1
Options Multi-GNSS Timing Module,
Oven Oscillator
GPS Module,
Oven Oscillator
Environmental
Operating Temperature 10οto 55oC 10οto 55oC
Storage Temperature -40oto 70oC -40oto 70oC
Relative Humidity 10 to 90% (non-condensing) 10 to 90% (non-condensing)
Power
Consumption ~20 watts max ~20 watts max

RCIM User’s Guide
1-4

2-1
2
Chapter 1Hardware, Installation and Configuration
2
1
This chapter provides a description of the RCIM PCI-based boards as well as installation
and configuration information.
Board Descriptions 1
This section provides illustrations and descriptions of the RCIM IV and RCIM III boards.
The RCIM boards mount into a standard PCI Express slot on a host system. A connector is
mounted on each RCIM for connection to external interrupts, and a synchronization cable
is included for daisy-chaining a master RCIM to one or more slave RCIMs.

RCIM User’s Guide
2-2
RCIM IV 1
Board Illustration 1
Figure 2-1 shows the RCIM IV board with optional high stability OCXO (Oven
Controlled Crystal Oscillator) and GPS modules installed.
Figure 2-1 RCIM IV Board
GPS Module
Connectors
Oven
Controlled
Crystal
Oscillator
GPS Module

Hardware, Installation and Configuration
2-3
Connectors and LEDs 1
Figure 2-2 shows the input/output connectors and LEDs on the RCIM IV board. Detailed
information on the LEDs and each of the connectors is provided in the following sections.
Figure 2-2 RCIM IV Connectors and LED Locations
LED Functions 1
There are two bi-colored status LEDs near the input and output connectors on the
RCIM IV board. They will both glow dimly RED when the board is in reset mode
Output
Status LED
Input
Status LED
SFP Input
Connector
SFP Output
Connector
GPS Antenna
Connector
External Interrupt
I/O Connector

RCIM User’s Guide
2-4
followed by brief intervals of bright RED and GREEN as a test. During normal operation
of the board the LEDs function as follows:
Input and Output Cables and Connectors 1
The RCIM IV uses a pair of standard SFP (small form-factor pluggable) connectors
installed in cages to interface to the RCIM IV cable. The cable is used to communicate
interrupts, time stamps and a reference clock between RCIM IV boards. The output cable
connector is used when the RCIM is either the master or a slave in the middle of an RCIM
chain (see page 2-14 for a description of RCIM modes). The input cable connector is used
when the RCIM is acting in slave mode or in the middle of an RCIM chain. The cable part
number (HS002-3CBL-xx where xx is length in meters) includes an LC fiber optic cable
and two SFPs that are installed in the empty cages on the master and slave RCIMs. Refer
to the section “Daisy Chain Cable” for more information about the cable.
LED description Function
Output
Status
LED
RED solid 10 MHz clock failure
RED 2/sec flash POSIX clock stopped, with cable option, but cable
not synchronized or missing
GREEN 1/sec flash POSIX clock running, without cable option
GREEN 1/sec blink POSIX clock running, with cable option, and cable
synchronized
RED/GREEN alter-
nating 2/sec flash
POSIX clock running, with cable option, but cable
not synchronized or missing
BLUE 1/sec flash POSIX clock running, without cable option, and
receiving a valid GPS pulse
BLUE 1/sec blink POSIX clock running, with cable option, receiving
a valid GPS pulse, and cable synchronized
RED/BLUE alternat-
ing 2/sec flash
POSIX clock running, with cable option, receiving
a valid GPS pulse, but cable not synchronized or
missing
Input
Status
LED
RED 2/sec flash with cable option, but cable not synchronized or
missing
GREEN solid with cable option, and cable synchronized
BLUE 1/sec flash without cable option, but receiving a valid IRIG
pulse
BLUE 1/sec blink with cable option, receiving a valid IRIG pulse, and
cable synchronized
RED/BLUE alternat-
ing 2/sec flash
with cable option, receiving a valid IRIG pulse, but
cable not synchronized or missing

Hardware, Installation and Configuration
2-5
NOTE
The cable SFPs should only be installed and removed with the
system containing the RCIM IV powered down. See the Installa-
tion section for ESD caution. Care should be taken to insure that
the SFP modules lock into position and that the RCIM IV is not
pushed out of its PCIe slot during the installation of the SFPs. The
fiber optic cables themselves can be installed and removed at any
time without damaging the RCIM IV.
Oscillators 1
The temperature compensated crystal oscillator (TCXO) provided with RCIM IV has an
accuracy of +/- 1.0 PPM (parts per million).
One optional oven controlled crystal oscillator (OCXO) provides a temperature stability of
+/- 10 PPB (parts per billion).
GPS Antenna 1
The GPS option on the RCIM IV includes an active GPS antenna and coaxial cable.
The antenna receives the GPS satellite signals and passes them to the receiver. The GPS
signals are spread spectrum signals in the 1575 MHz range and do not penetrate
conductive or opaque surfaces. Therefore, the antenna must be located outdoors with a
clear view of the sky.
If a different antenna or cable is used, it should match the following specifications:
•50 Ohm impedence
•27 dB gain
•3.3 volt DC power max 30 ma.
External Interrupt I/O Connector 1
The external interrupt I/O connector on the RCIM IV is an industry standard 26-pin High
Density D-SUB that provides twelve shared outputs and/or inputs.
The external EXT_INOUT pins allow equipment to communicate with the RCIM via I/O
interrupts that are software selectable to be either inputs or outputs with a switchable 100
Ohm termination. The function of each pin is driven by a multiplexer that can set
individual pins to be either an input or an output. Pins set as outputs may be driven by any
of the following RCIM devices: programmable interrupt generators (PIGs), real-time
clock timers, (RTCs), edge-triggered interrupts (also known as input pins or ETIs), or
distributed interrupts (DIs). Each pin is physically wired to be both an input and an output
with the ability to disable the output gate. If no external wire is connected to an RCIM pin,
the pin can act as both an input and output simultaneously for loopback connections.
By default, pins EXT_INOUT0 through EXT_INOUT5 are configured to be both inputs
and outputs, and pins EXT_INOUT6 through EXT_INOUT11 are configured to be only
inputs. See “RCIM IV Pin Configuration” on page 3-20 for more information.

RCIM User’s Guide
2-6
See Chapter 3 for information on using external output interrupts and programmable
interrupts.
The pin-outs for the external interrupt I/O connector are shown in Figure 2-3.
Figure 2-3 RCIM IV External Interrupt I/O Connector Pin-outs
RCIM IV external interrupt inputs have a selectable termination of 100 Ohms and are
capable of 3.3V or 5V TTL levels. The recommended input signal duration is 1us and
because termination can be disabled there is no minimum amperage requirement for line
drivers.
The RCIM IV currently does not support any programmable input sources. However,
future revisions of the RCIM IV will support two programmable input sources, DCLS
input and an external 10Mhz clock, that can be assigned to a physical pin to discipline the
masterclock. The DCLS input will enable digital IRIG input, and the external 10Mhz
clock input will automatically discipline the RCIM masterclock regardless of what other
clocksources exist on the RCIM.
The signals EXT_RXD and EXT_TXD are RS-232 level signals. They are currently used for
debug purposes.
X
1
EXT_INOUT0
2
EXT_INOUT1
3
EXT_INOUT2
4
EXT_INOUT3
5
EXT_INOUT4
6
EXT_INOUT5
7
EXT_INOUT6
8
EXT_INOUT7
9
EXT_INOUT8
26
EXT_INOUT9
25
EXT_INOUT10
24
EXT_INOUT11
23
22
EXT_AMOUT
21
EXT_AMIN
20
EXT_TXD
19
EXT_RXD
18
GND
17
GND
16
GND
15
GND
14
GND
13
GND
12
GND
11
GND
10
GND

Hardware, Installation and Configuration
2-7
System Identification 1
The following output to lspci(8) shows the PCI class, vendor and device IDs for the
RCIM IV (1b:00.0 (bus:slot.function) will differ on your system):
# lspci -v | grep -i rcim
1b:00.0 System peripheral: Concurrent Real-Time RCIM-IV Real-Time
Clock & Interrupt Module (PCIe) (rev 01)
Kernel driver in use: rcim
Kernel modules: rcim
# lspci -ns 1b:00.0
1b:00.0 0880: 1542:9273 (rev 01)
Daisy Chain Cable 1
The RCIM IV uses a fiber optic serial synchronization cable with SFP (small form-factor
pluggable) connectors (part no. HS002-3CBL-xx) to connect RCIM IVs in an RCIM
chain. The serial data on the cable includes parity and framing information which allow
cable problems to be detected. Polling is done continuously and messages that report the
status of the RCIM IV daisy chain cables are output when an error condition is detected.
Messages indicating problems will appear on the systems directly connected by a failing
link.
The serial cables are point to point connections. The “input” cable refers to the cable going
upstream towards the master RCIM. The “output” cable is the downstream connection
away from the master.
RCIM: Input cable disconnected.
RCIM: Input cable connected.
RCIM: Input cable connected but not synchronized.
RCIM: Input cable unsynchronized.
RCIM: Input cable O.K.
RCIM: Output cable disconnected.
RCIM: Output cable connected.
RCIM: Output cable connected but not synchronized.
RCIM: Output cable unsynchronized.
RCIM: Output cable O.K.
RCIM: Cable error on input cable.
RCIM: Cable error on output cable.
The “disconnected” and “connected” messages will only occur based on whether an SFP
is installed in the appropriate cage of the RCIM IV.
They will not occur when the optical cable is inserted or removed. They should not occur
during normal operation unless the SFP is not installed correctly or it is malfunctioning.
The “not synchronized” and “unsynchronized” messages indicate that the cable is not
answering attempts to communicate. These messages will occur when the optical cable is
installed or removed. They will also occur when a connected system is powered off.

RCIM User’s Guide
2-8
The last two messages indicate transient errors such as cable parity errors or temporary
loss of cable synchronization. If a transient error occurs, it may require a link in the cable
to resynchronize. If a distributed interrupt is being broadcast on the cable, it may be lost.
Transient errors also affect the synchronization of the tick timers since the cable clock will
not reach all of the systems. Refer to Chapter 3 for instructions for synchronizing clocks.
RCIM III 1
Board Illustration 1
Figure 2-4 shows the RCIM III board with optional high stability OCXO (Oven
Controlled Crystal Oscillator) and GPS modules installed.
Figure 2-4 RCIM III Board
GPS Module
Connectors
Oven
Controlled
Crystal
Oscillator

Hardware, Installation and Configuration
2-9
Connectors and LEDs 1
Figure 2-5 shows the input/output connectors and LEDs on the RCIM III board. Detailed
information on the LEDs and each of the connectors is provided in the following sections.
Figure 2-5 RCIM III Connectors and LED Locations
LED Functions 1
There are two bi-colored status LEDs near the input and output connectors on the
RCIM III board. They will both glow dimly RED when the board is in reset mode
Output
Status LED
Input
Status LED
SFP Input
Connector
SFP Output
Connector
GPS Antenna
Connector
External Interrupt
I/O Connector

RCIM User’s Guide
2-10
followed by brief intervals of bright RED and GREEN as a test. During normal operation
of the board the LEDs function as follows:
Input and Output Cables and Connectors 1
The RCIM III uses a pair of standard SFP (small form-factor pluggable) connectors
installed in cages to interface to the RCIM III cable. The cable is used to communicate
interrupts, time stamps and a reference clock between RCIM III boards. The output cable
connector is used when the RCIM is either the master or a slave in the middle of an RCIM
chain (see page 2-14 for a description of RCIM modes). The input cable connector is used
when the RCIM is acting in slave mode or in the middle of an RCIM chain. The cable part
number (HS002-3CBL-xx where xx is length in meters) includes an LC fiber optic cable
and two SFPs that are installed in the empty cages on the master and slave RCIMs. Refer
to the section “Daisy Chain Cable” for more information about the cable.
NOTE
The cable SFPs should only be installed and removed with the
system containing the RCIM III powered down. See the Installa-
tion section for ESD caution. Care should be taken to insure that
the SFP modules lock into position and that the RCIM III is not
pushed out of its PCIe slot during the installation of the SFPs. The
fiber optic cables themselves can be installed and removed at any
time without damaging the RCIM III.
Oscillators 1
The temperature compensated crystal oscillator (TCXO) provided with RCIM III has an
accuracy of +/- 2.5 PPM (parts per million).
One optional oven controlled crystal oscillators (OCXO) provides a temperature stability
of 10 PPB (parts per billion).
LED description Function
Output
Status
LED
RED solid 10 MHz clock failure
RED 2/sec flash POSIX clock stopped, with cable option, but cable
not synchronized or missing
GREEN 1/sec flash POSIX clock running, without cable option
GREEN 1/sec blink POSIX clock running, with cable option, and cable
synchronized
RED/GREEN alter-
nating 2/sec flash
POSIX clock running, with cable option, but cable
not synchronized or missing
Input
Status
LED
RED 2/sec flash with cable option, but cable not synchronized or
missing
GREEN solid with cable option, and cable synchronized