The mbboDirect record performs the opposite function to that of the mbbiDirect record. It accumulates bits (in the fields B0 - BF) as unsigned characters, and converts them to a word which is then written out to hardware. If a bit field is non-zero, it is interpreted as a binary 1. On the other hand, if it is zero, it is interpreted as a binary 0.
The record-specific fields are described below, grouped by functionality.
The mbboDirect record has the standard fields for specifying under what circumstances it will be processed. These fields are listed in Scan Fields.
The mbboDirect record,
like all output records,
must specify where its output originates.
The output mode select field (OMSL) determines whether the output originates from another record or from database access.
When set to closed_loop,
the desired output is retrieved from the link specified in the desired output (DOL) field--which can specify either a database or channel access link--and placed into the VAL field.
When set to supervisory,
the DOL field is ignored and the current value of VAL is used.
The desired output can be written into the VAL field via dpPuts at run-time when the record is in supervisory mode.
DOL can also be a constant,
in which case VAL is initialized to the constant value.
Note that OMSL cannot be closed_loop when DOL is a constant.
VAL is then converted to RVAL in the routine described in the next section.
However,
the Soft Channel device support module for the mbboDirect record writes the VAL field's value without any conversion.
Field Summary Type DCT Default Read Write CA PP OMSL Output Mode Select MENU (menuOmsl) Yes Yes Yes Yes DOL Desired Output Loc INLINK Yes Yes Yes No VAL Word LONG Yes Yes Yes Yes
For records that are to write values to hardware devices, the OUT output link must contain the address of the I/O card, and the DTYP field must specify the proper device support module. Be aware that the address format differs according to the I/O bus used. See "Address Specification" for information on the format of hardware addresses.
If the mbboDirect record does not use the Soft Channel device support module,
then VAL is converted to RVAL,
and RVAL is the actual 16-bit word sent out.
RVAL is set equal to VAL and then shifted left by the number of bits specified in the SHFT field (the SHFT value is set by device support and is not configurable by the user).
RVAL is then sent out to the location specified in the OUT field.
For mbboDirect records that specify a database link,
a channel access link,
or a constant,
the DTYP field must specify either one of two soft device support routines--{Soft Channel} or Raw Soft Channel.
The difference between the two is that Soft Channel writes the desired output value from VAL directly to the output link while Raw Soft Channel writes the value from RVAL to the output link after it has undergone the conversion described above.
Field Summary Type DCT Default Read Write CA PP OUT Output Specification OUTLINK Yes Yes Yes No RVAL Raw Value ULONG No Yes No Yes SHFT Shift USHORT Yes Yes Yes No B0 Bit 0 UCHAR Yes Yes Yes Yes B1 Bit 1 UCHAR Yes Yes Yes Yes B2 Bit 2 UCHAR Yes Yes Yes Yes B3 Bit 3 UCHAR Yes Yes Yes Yes B4 Bit 4 UCHAR Yes Yes Yes Yes B5 Bit 5 UCHAR Yes Yes Yes Yes B6 Bit 6 UCHAR Yes Yes Yes Yes B7 Bit 7 UCHAR Yes Yes Yes Yes B8 Bit 8 UCHAR Yes Yes Yes Yes B9 Bit 9 UCHAR Yes Yes Yes Yes BA Bit 10 UCHAR Yes Yes Yes Yes BB Bit 11 UCHAR Yes Yes Yes Yes BC Bit 12 UCHAR Yes Yes Yes Yes BD Bit 13 UCHAR Yes Yes Yes Yes BE Bit 14 UCHAR Yes Yes Yes Yes BF Bit 15 UCHAR Yes Yes Yes Yes
See Fields Common to All Record Types for more on the record name (NAME) and description (DESC) fields.
Field Summary Type DCT Default Read Write CA PP NAME Record Name STRING [61] No Yes No No DESC Descriptor STRING [41] Yes Yes Yes No
These parameters are used by the run-time code for processing the mbbo Direct record.
MASK is used by device support routine to read the hardware register. Record support sets low order NOBT bits. Device support can shift this value.
MLST holds the value when the last monitor for value change was triggered.
Field Summary Type DCT Default Read Write CA PP NOBT Number of Bits SHORT Yes Yes No No ORAW Prev Raw Value ULONG No Yes No No MASK Hardware Mask ULONG No Yes No No MLST Last Value Monitored LONG No Yes No No
The following fields are used to operate the record in simulation mode.
If SIMM (fetched through SIML) is YES, the record is put in SIMS severity and the value is written through SIOL, without conversion. SSCN sets a different SCAN mechanism to use in simulation mode. SDLY sets a delay (in sec) that is used for asynchronous simulation processing.
See Output Simulation Fields for more information on simulation mode and its fields.
Field Summary Type DCT Default Read Write CA PP SIML Simulation Mode Link INLINK Yes Yes Yes No SIMM Simulation Mode MENU (menuYesNo) No Yes Yes No SIOL Simulation Output Link OUTLINK Yes Yes Yes No SIMS Simulation Mode Severity MENU (menuAlarmSevr) Yes Yes Yes No SDLY Sim. Mode Async Delay DOUBLE Yes -1.0 Yes Yes No SSCN Sim. Mode Scan MENU (menuScan) Yes 65535 Yes Yes No
The possible alarm conditions for mbboDirect records are the SCAN, READ, and INVALID alarms. The SCAN and READ alarms are not configurable by the user since they are always of MAJOR severity. See "Alarm Specification" for a complete explanation of Scan and Read alarms.
The IVOA field specifies an action to take when the INVALID alarm is triggered.
There are three possible actions: Continue normally,
Don't drive outputs,
or Set output to IVOV.
When Set output to IVOV is specified and a INVALID alarm is triggered,
the record will write the value in the IVOV field to output.
See Invalid Output Action Fields for more information.
Alarm Fields lists the fields related to alarms that are common to all record types.
Field Summary Type DCT Default Read Write CA PP IVOA INVALID outpt action MENU (menuIvoa) Yes Yes Yes No IVOV INVALID output value LONG Yes Yes Yes No
This routine initializes SIMM if SIML is a constant or creates a channel access link if SIML is PV_LINK. If SIOL is PV_LINK a channel access link is created.
This routine next checks to see that device support is available.The routine next checks to see if the device support write routine is defined. If either device support or the device support write routine does not exist, an error message is issued and processing is terminated.
If DOL is a constant, then VAL is initialized to its value and UDF is set to FALSE.
MASK is cleared and then the NOBT low order bits are set.
If device support includes init_record(),
it is called.
If device support returns success, VAL is then set from RVAL and UDF is set to FALSE.
See next section.
Routine process implements the following algorithm:
Each mbboDirect record must have an associated set of device support routines. The primary responsibility of the device support routines is to obtain a new raw mbbo value whenever write_mbboDirect is called. The device support routines are primarily interested in the following fields:
Field Summary Type DCT Default Read Write CA PP PACT Record active UCHAR No Yes No No DPVT Device Private NOACCESS No No No No UDF Undefined UCHAR Yes 1 Yes Yes Yes NSEV New Alarm Severity MENU (menuAlarmSevr) No Yes No No NSTA New Alarm Status MENU (menuAlarmStat) No Yes No No NOBT Number of Bits SHORT Yes Yes No No OUT Output Specification OUTLINK Yes Yes Yes No RVAL Raw Value ULONG No Yes No Yes RBV Readback Value ULONG No Yes No No MASK Hardware Mask ULONG No Yes No No SHFT Shift USHORT Yes Yes Yes No
Device support consists of the following routines:
This optional routine is called by the IOC command 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 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.
This optional routine is called twice at IOC initialization time.
The first call happens before any of the init_record() calls are made,
with the integer parameter after set to 0.
The second call happens after all of the init_record() calls have been made,
with after set to 1.
init_record(precord)
This routine is optional. If provided, it is called by the record support init_record() routine. If MASK is used, it should be shifted if necessary and SHFT given a value.
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.
write_mbboDirect(precord)
This routine must output a new value. It returns the following values:
This SOft Channel module writes the current value of VAL.
If the OUT link type is PV_LINK, then dbCaAddInlink is called by init_record().
write_mbboDirect calls recGblPutLinkValue to write the current value of VAL.
See Soft Output.