#*************************************************************************
# Copyright (c) 2002 The University of Chicago, as Operator of Argonne
#     National Laboratory.
# Copyright (c) 2002 The Regents of the University of California, as
#     Operator of Los Alamos National Laboratory.
# EPICS BASE is distributed subject to a Software License Agreement found
# in file LICENSE that is included with this distribution.
#*************************************************************************

=title Waveform Record (waveform)

The waveform record type is used to interface waveform digitizers. The record
stores its data in arrays. The array can contain any of the supported data
types.

=recordtype waveform

=cut

include "menuFtype.dbd"

menu(waveformPOST) {
    choice(waveformPOST_Always,"Always")
    choice(waveformPOST_OnChange,"On Change")
}

recordtype(waveform) {

=head2 Parameter Fields

The record-specific fields are described below, grouped by functionality.

=head3 Scan Parameters

The waveform record has the standard fields for specifying under what
circumstances the record will be processed. These fields are listed in L<Scan
Fields>. In addition, L<Scanning Specification> explains how these fields are
used. Note that I/O event scanning is only supported for those card types that
interrupt.

=head3 Read Parameters

These fields are configurable by the user to specify how and from where the
record reads its data. How the INP field is configured determines where the
waveform gets its input. It can be a hardware address, a channel access or
database link, or a constant. Only in records that use soft device support can
the INP field be a channel access link, a database link, or a constant.
Otherwise, the INP field must be a hardware address. See L<Address
Specification> for information on the format of hardware addresses and database
links.

=head4 Fields related to waveform reading

=fields DTYP, INP, NELM, FTVL, RARM

The DTYP field must contain the name of the appropriate device support module.
The values retrieved from the input link are placed in an array referenced by
VAL. (If the INP link is a constant, elements can be placed in the array via
dbPuts.) NELM specifies the number of elements that the array will hold, while
FTVL specifies the data type of the elements.
The RARM field causes the device to re-arm when this field is set to 1.

=head4 Possible data types for FTVL

=menu menuFtype

=head3 Operator Display Parameters

These parameters are used to present meaningful data to the operator. They
display the value and other parameters of the waveform either textually or
graphically.

=head4 Fields related to I<Operator Display>

=fields EGU, HOPR, LOPR, PREC, NAME, DESC

EGU is a string of up to 16 characters describing the units that the waveform
measures. It is retrieved by the C<<< get_units >>> record support routine.

The HOPR and LOPR fields set the upper and lower display limits for array
elements referenced by the VAL field. Both the C<<< get_graphic_double >>> and
C<<< get_control_double >>> record support routines retrieve these fields.

The PREC field determines the floating point precision with which to display the
array values. It is used whenever the C<<< get_precision >>> record support
routine is called.

See L<Fields Common to All Record Types> for more on the record name (NAME) and
description (DESC) fields.


=head3 Alarm Parameters

The waveform record has the alarm parameters common to all record types. L<Alarm
Fields> lists other fields related to a alarms that are common to all record
types.

=head3 Monitor Parameters

These parameters are used to determine when to send monitors placed on the VAL
field. The APST and MPST fields are a menu with choices "Always" and "On
Change". The default is "Always", thus monitors will normally be sent every time
the record processes. Selecting "On Change" causes a 32-bit hash of the VAL
field buffer to be calculated and compared with the previous hash value every
time the record processes; the monitor will only be sent if the hash is
different, indicating that the buffer has changed. Note that there is a small
chance that two different value buffers might result in the same hash value, so
for critical systems "Always" may be a better choice, even though it re-sends
duplicate data.

=head4 Record fields related to I<Monitor Parameters>

=fields APST, MPST, HASH

=head4 Menu choices for C<APST> and C<MPST> fields

=menu waveformPOST

=head3 Run-time Parameters

These parameters are used by the run-time code for processing the waveform. They
are not configured using a configuration tool. Only the VAL field is modifiable
at run-time.

VAL references the array where the waveform stores its data. The BPTR field
holds the address of the array.

The NORD field holds a counter of the number of elements that have been read
into the array. It is reset to 0 when the device is rearmed. The BUSY field
indicates if the device is armed but has not yet been digitized.

=fields VAL, BPTR, NORD, BUSY

The following fields are used to operate the waveform in the simulation mode.
See L<Simulation Mode> for more information on the simulation mode fields.

=fields SIOL, SIML, SIMM, SIMS

=begin html

<br>
<hr>
<br>

=end html

=head2 Record Support

=head3 Record Support Routines

=head4 init_record

   static long init_record(waveformRecord *prec, int pass)

Using NELM and FTVL space for the array is allocated. The array address is
stored in the record.

This routine initializes SIMM with the value of SIML if SIML type is CONSTANT
link or creates a channel access link if SIML type is PV_LINK. VAL is likewise
initialized if SIOL is CONSTANT or PV_LINK.

This routine next checks to see that device support is available and a device
support read routine is defined. If either does not exist, an error message is
issued and processing is terminated

If device support includes C<init_record()>, it is called.

=head4 process

  static long process(waveformRecord *prec)

See L</"Record Processing"> section below.

=head4 cvt_dbaddr

  static long cvt_dbaddr(DBADDR *paddr)

This is called by dbNameToAddr. It makes the dbAddr structure refer to the
actual buffer holding the result.

=head4 get_array_info

  static long get_array_info(DBADDR *paddr, long *no_elements, long *offset)

Obtains values from the array referenced by VAL.

=head4 put_array_info

  static long put_array_info(DBADDR *paddr, long nNew)

Writes values into the array referenced by VAL.

=head4 get_units

  static long get_units(DBADDR *paddr, char *units)

Retrieves EGU.

=head4 get_prec

  static long get_precision(DBADDR *paddr, long *precision)

Retrieves PREC if field is VAL field. Otherwise, calls C<<< recGblGetPrec() >>>.

=head4 get_graphic_double

  static long get_graphic_double(DBADDR *paddr, struct dbr_grDouble *pgd)

Sets the upper display and lower display limits for a field. If the field is VAL
the limits are set to HOPR and LOPR, else if the field has upper and lower
limits defined they will be used, else the upper and lower maximum values for
the field type will be used.

Sets the following values:

  upper_disp_limit = HOPR
  lower_disp_limit = LOPR

=head4 get_control_double

  static long get_control_double(DBADDR *paddr, struct dbr_ctrlDouble *pcd)

Sets the upper control and the lower control limits for a field. If the field is
VAL the limits are set to HOPR and LOPR, else if the field has upper and lower
limits defined they will be used, else the upper and lower maximum values for
the field type will be used.

Sets the following values

  upper_ctrl_limit = HOPR
  lower_ctrl_limit = LOPR

=head3 Record Processing

Routine process implements the following algorithm:

=over

=item 1.

Check to see that the appropriate device support module exists. If it doesn't,
an error message is issued and processing is terminated with the PACT field
still set to TRUE. This ensures that processes will no longer be called for this
record. Thus error storms will not occur.

=item 2.

Call device support read routine.

=item 3.

If PACT has been changed to TRUE, the device support read routine has started
but has not completed writing the new value. In this case, the processing
routine merely returns, leaving PACT TRUE.

=item 4.

Check to see if monitors should be invoked.

=over

=item *

Alarm monitors are invoked if the alarm status or severity has changed.

=item *

Archive and value change monitors are invoked if APST or MPST are Always or if
the result of the hash calculation is different.

=item *

NSEV and NSTA are reset to 0.

=back

=item 5.

Scan forward link if necessary, set PACT FALSE, and return.

=back

=begin html

<br>
<hr>
<br>

=end html

=head2 Device Support

=head3 Fields Of Interest To Device Support

Each waveform record must have an associated set of device support routines. The
primary responsibility of the device support routines is to obtain a new array
value whenever read_wf is called. The device support routines are primarily
interested in the following fields:

=fields PACT, DPVT, NSEV, NSTA, INP, NELM, FTVL, RARM, BPTR, NORD, BUSY

=head3 Device Support Routines

Device support consists of the following routines:

=head4 report

  long report(int level)

This optional routine is called by the IOC command C<dbior> and is passed the
report level that was requested by the user.
It should print a report on the state of the device support to stdout.
The C<level> parameter may be used to output increasingly more detailed
information at higher levels, or to select different types of information with
different levels.
Level zero should print no more than a small summary.

=head4 init

  long init(int after)

This optional routine is called twice at IOC initialization time.
The first call happens before any of the C<init_record()> calls are made, with
the integer parameter C<after> set to 0.
The second call happens after all of the C<init_record()> calls have been made,
with C<after> set to 1.

=head4 init_record

  long init_record(dbCommon *precord)

This routine is optional. If provided, it is called by the record support
C<init_record()> routine.

=head4 get_ioint_info

  long get_ioint_info(int cmd, 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.

=head4 read_wf

  long read_wf(waveformRecord *prec)

This routine must provide a new input value. It returns the following values:

=over

=item *

0: Success.

=item *

Other: Error.

=back

=head3 Device Support For Soft Records

The C<<< Soft Channel >>> device support module is provided to read values from
other records and store them in arrays. If INP is a constant link, then read_wf
does nothing. In this case, the record can be used to hold arrays written via
dbPuts. If INP is a database or channel access link, the new array value is read
from the link. NORD is set to the number of items in the array.

This module places a value directly in VAL.

If the INP link type is constant, then NORD is set to zero.

=cut

	include "dbCommon.dbd"
	field(VAL,DBF_NOACCESS) {
		prompt("Value")
		asl(ASL0)
		special(SPC_DBADDR)
		pp(TRUE)
		extra("void *		val")
		#=type Set by FTVL
		#=read Yes
		#=write Yes
	}
	field(RARM,DBF_SHORT) {
		prompt("Rearm the waveform")
		promptgroup("30 - Action")
		pp(TRUE)
		interest(1)
	}
	field(PREC,DBF_SHORT) {
		prompt("Display Precision")
		promptgroup("80 - Display")
		interest(1)
		prop(YES)
	}
	field(INP,DBF_INLINK) {
		prompt("Input Specification")
		promptgroup("40 - Input")
		interest(1)
	}
	field(EGU,DBF_STRING) {
		prompt("Engineering Units")
		promptgroup("80 - Display")
		interest(1)
		size(16)
		prop(YES)
	}
	field(HOPR,DBF_DOUBLE) {
		prompt("High Operating Range")
		promptgroup("80 - Display")
		interest(1)
		prop(YES)
	}
	field(LOPR,DBF_DOUBLE) {
		prompt("Low Operating Range")
		promptgroup("80 - Display")
		interest(1)
		prop(YES)
	}
	field(NELM,DBF_ULONG) {
		prompt("Number of Elements")
		promptgroup("30 - Action")
		special(SPC_NOMOD)
		interest(1)
		initial("1")
	}
	field(FTVL,DBF_MENU) {
		prompt("Field Type of Value")
		promptgroup("30 - Action")
		special(SPC_NOMOD)
		interest(1)
		menu(menuFtype)
	}
	field(BUSY,DBF_SHORT) {
		prompt("Busy Indicator")
		special(SPC_NOMOD)
	}
	field(NORD,DBF_ULONG) {
		prompt("Number elements read")
		special(SPC_NOMOD)
	}
	field(BPTR,DBF_NOACCESS) {
		prompt("Buffer Pointer")
		special(SPC_NOMOD)
		interest(4)
		extra("void *		bptr")
	}
	field(SIOL,DBF_INLINK) {
		prompt("Sim Input Specifctn")
		promptgroup("90 - Simulate")
		interest(1)
	}
	field(SIML,DBF_INLINK) {
		prompt("Sim Mode Location")
		promptgroup("90 - Simulate")
		interest(1)
	}
	field(SIMM,DBF_MENU) {
		prompt("Simulation Mode")
		interest(1)
		menu(menuYesNo)
	}
	field(SIMS,DBF_MENU) {
		prompt("Sim mode Alarm Svrty")
		promptgroup("90 - Simulate")
		interest(2)
		menu(menuAlarmSevr)
	}
	field(MPST,DBF_MENU) {
		prompt("Post Value Monitors")
		promptgroup("80 - Display")
		interest(1)
		menu(waveformPOST)
	}
	field(APST,DBF_MENU) {
		prompt("Post Archive Monitors")
		promptgroup("80 - Display")
		interest(1)
		menu(waveformPOST)
	}
	field(HASH,DBF_ULONG) {
		prompt("Hash of OnChange data.")
		interest(3)
	}
}
