EPICS Record Reference Manual
Chapter 14: Event
The normal use for this record type is to post an event and/or process a
forward link. Device support for this record can provide a hardware
interrupt handler routine for I/O Event-scanned records. The records in
this field fall into the following groups of parameters:
event number parameters
simulation mode parameters
2. Scan Parameters
The event record has the standard fields for specifying under what
circumstances it will be processed. If the SCAN field specifies
Intr, then device support will provide an interrupt handler,
posting an event number when an I/O interrupt occurs. These fields are
listed in Scan
Fields, Chapter 2, 2. In addition, Scanning
Specification, Chapter 1, 1, explains how the scanning fields
work. Note that I/O event scanning is only supported for those card
types that interrupt.
3. Input Specification
The device support routines use the address in this record to obtain
input. For records that provide an interrupt handler, the INP field
should specify the address of the I/O card, and the DTYP field should
specify a valid device support module. Be aware that the address format
differs according to the card type used. See Address
Specification, Chapter 1, 2, for information on the format of
hardware addresses and specifying links. You can see a list of the
device support modules currently supported at the user's local site by
using the dbst utility in R3.13.
For soft records, the INP field can be a constant, a database link, or a
channel access link. For soft records, the DTYP field should specify
|DTYP||Device Type||DEVCHOICE||Yes||0||Yes||No||No|| |
4. Event Number Parameters
The VAL field contains the event number read by the device support
routines. It is this number which is posted. For records that use
Channel device support, it can be configured before run-time or
set via dbPuts.
|VAL||Event Number to Post||USHORT||Yes||0||Yes||Yes||Yes||No|
5. Operator Display Parameters
2, Fields Common to All Record Types, for more on the
record name (NAME) and description (DESC) fields.
|NAME||Record Name||STRING ||Yes||0||Yes||No||No|| |
6. Alarm Parameters
The Event record has the alarm parameters common to all record types. Alarm
Fields, Chapter 2, 3, lists other fields related to a alarms
that are common to all record types.
7. Simulation Mode Parameters
The following fields are used to operate the event record in the
simulation mode. See Chapter
3, Fields Common to Many Record Types, for more
information on these fields.
|SIOL||Simulation Value Location||INLINK||Yes||0||No||No||N/A||No|
|SIML||Simulation Mode Location||INLINK||Yes||0||No||No||N/A||No|
|SIMS||Simulation Mode Alarm Severity||GBLCHOICE||Yes||0||Yes||Yes||No||No|
8. Record Support Routines
This routine initializes SIMM with the value of SIML if SIML type is a
CONSTANT link or creates a channel access link if SIML type is PV_LINK.
SVAL is likewise initialized if SIOL is CONSTANT or PV_LINK.
If device support includes init_record, it is called.
See next section.
Fills in the values of struct valueDes so that they refer to VAL.
9. Record Processing
Routine process implements the following algorithm:
- 1. readValue is called. See Input
Records, Chapter 3, 2, for more information.
- 2. If PACT has been changed to TRUE, the device
support read routine has started but has not completed reading a new
input value. In this case, the processing routine merely returns,
leaving PACT TRUE.
- 3. If VAL > 0, post event number VAL.
- 4. Check to see if monitors should be invoked.
Alarm monitors are invoked if the alarm status or severity has changed
NSEV and NSTA are reset to 0.
- 5. Scan forward link if necessary, set PACT
FALSE, and return.
10. Device Support
10.1. Fields of Interest To Device Support
Each record must have an associated set of device support routines. The
device support routines are primarily interested in the following
|PACT||Processing Active||See Chapter
2, Fields Common to All Record Types, for an explanation
of these fields.|
|NSEV||New Alarm Severity|
|NSTA||New Alarm Status|
|INP||Input Link||This field is used by the device
support routines to locate its input.|
|PRIO||Priority||This value must be used by the device
support interrupt handler to set the scheduling priority for processing
10.2. Device Support Routines
Device support consists of the following routines:
report(FILE fp, interest)
Not currently used.
This routine is called once during IOC initialization.
This routine is optional. If provided, it is called by the record
support init_record routine.
get_ioint_info(int cmd,struct dbCommon *precord,IOSCANPVT *ppvt)
This routine is called by the ioEventScan system each time the record is
added or deleted from an I/O event scan list. cmd has the value (0,1)
if the record is being (added to, deleted from) an I/O event list. It
must be provided for any device type that can use the ioEvent scanner.
This routine returns the following values:
- 0: Success.
- Other: Error.
10.3. Device Support For Soft Records
Soft Channel device support module is available. The
INP link type must be either CONSTANT, DB_LINK, or CA_LINK.
If the INP link type is CONSTANT, then the constant value is stored into
VAL by init_record, and UDF is set to FALSE. If the INP link type is
PV_LINK, then dbCaAddInlink is called by init_record.
read_event calls recGblGetLinkValue to read the current
value of VAL. See Input
Records, Chapter 3, 2, for details on soft input.
1. - Introduction
2. - Scan Parameters
3. - Input Specification
4. - Event Number Parameters
5. - Operator Display Parameters
6. - Alarm Parameters
7. - Simulation Mode Parameters
8. - Record Support Routines
9. - Record Processing
10. - Device Support
- Fields of Interest To Device Support
- Device Support Routines
- Device Support For Soft Records
EPICS Record Reference Manual - 19 MAY 1998
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