GPIB Bus Interface (INTFC) Resource

This topic describes the GPIB Bus Interface (INTFC) Resource that is provided to encapsulate the operations and properties of a raw GPIB interface (reading, writing, triggering, etc.).

INTFC Resource Overview

A VISA GPIB Bus Interface (INTFC) Resource, like any other resource, defines the basic operations and attributes of the VISA Resource Template.

For example, modifying the state of an attribute is done via the operation viSetAttribute. Although the INTFC resource does not have viSetAttribute listed in its operations, it provides the operation because it is defined in the VISA Resource Template. From this basic set, each resource adds its specific operations and attributes that allow it to perform its dedicated task.

The INTFC Resource lets a controller interact with any devices connected to the board associated with this resource. Services are provided to send blocks of data onto the bus, request blocks of data from the bus, trigger devices on the bus, and send miscellaneous commands to any or all devices. In addition, the controller can directly query and manipulate specific lines on the bus and also pass control to other devices with controller capability.

INTFC Resource Attributes

Attribute Name	Attribute Value	Access Privileges		Data Type	Range	Default
Generic INTFC Resource Attributes
VI_ATTR_DEV_STATUS_BYTE	0x3FFF0189UL	RW	Global	ViUInt8	0 to FFh	N/A
VI_ATTR_DMA_ALLOW_EN	0x3FFF001EUL	RW	Local	ViBoolean	VI_TRUE VI_FALSE	VI_TRUE
VI_ATTR_FILE_APPEND_EN	0x3FFF0192UL	RW	Local	ViBoolean	VI_TRUE VI_FALSE	VI_FALSE
VI_ATTR_INTF_INST_NAME	0xBFFF00E9UL	RO	Global	ViString	N/A	N/A
VI_ATTR_INTF_NUM	0x3FFF0176UL	RO	Global	ViUInt16	0 to FFFFh	0
VI_ATTR_INTF_TYPE	0x3FFF0171UL	RO	Global	ViUInt16	VI_INTF_GPIB	VI_INTF_GPIB
VI_ATTR_RD_BUF_OPER_MODE	0x3FFF002AUL	RW	Local	ViUInt16	VI_FLUSH_ON_ACCESS VI_FLUSH_DISABLE	VI_FLUSH_ DISABLE
VI_ATTR_SEND_END_EN	0x3FFF0016UL	RW	Local	ViBoolean	VI_TRUE VI_FALSE	VI_TRUE
VI_ATTR_TERMCHAR	0x3FFF0018UL	RW	Local	ViUInt8	0 to FFh	0Ah (linefeed)
VI_ATTR_TERMCHAR_EN	0x3FFF0038UL	RW	Local	ViBoolean	VI_TRUE VI_FALSE	VI_FALSE
VI_ATTR_TMO_VALUE	0x3FFF001AUL	RW	Local	ViUInt32	VI_TMO_IMMEDIATE 1 to FFFFFFFEh	2000 msec
VI_ATTR_WR_BUF_OPER_MODE	0x3FFF002DUL	RW	Local	ViUInt16	VI_FLUSH_ON_ACCESS VI_FLUSH_WHEN_FULL	VI_FLUSH_WHEN_FULL
VI_ATTR_RD_BUF_SIZE	0x3FFF002BUL	RO	Local	ViUInt32	N/A	N/A
VI_ATTR_WR_BUF_SIZE	0x3FFF002EUL	RO	Local	ViUInt32	N/A	N/A
GPIB-Specific INTFC Resource Attributes
VI_ATTR_GPIB_ADDR_STATE	0x3FFF005CUL	RO	Global	ViInt16	VI_GPIB_UNADDRESSED VI_GPIB_TALKER VI_GPIB_LISTENER	N/A
VI_ATTR_GPIB_HS488_CBL_LEN	0x3FFF0069UL	RW	Global	ViInt16	1 to 15 VI_GPIB_HS488_DISABLED VI_GPIB_HS488_NIMPL	N/A
VI_ATTR_GPIB_SECONDARY_ADDR	0x3FFF0173UL	RW	Global	ViUInt16	0 to 30 VI_NO_SEC_ADDR	VI_NO_SEC_ADDR
VI_ATTR_GPIB_ATN_STATE	0x3FFF0057UL	RO	Global	ViInt16	VI_STATE_ASSERTED VI_STATE_UNASSERTED VI_STATE_UNKNOWN	N/A
VI_ATTR_GPIB_CIC_ STATE	0x3FFF005EUL	RO	Global	ViBoolean	VI_TRUE VI_FALSE	N/A
VI_ATTR_GPIB_NDAC_ STATE	0x3FFF0062UL	RO	Global	ViInt16	VI_STATE_ASSERTED VI_STATE_UNASSERTED VI_STATE_UNKNOWN	N/A
VI_ATTR_GPIB_PRIMARY_ADDR	0x3FFF0172UL	RW	Global	ViUInt16	0 to 30	N/A
VI_ATTR_GPIB_REN_STATE	0x3FFF0181UL	RO	Global	ViInt16	VI_STATE_ASSERTED VI_STATE_UNASSERTED VI_STATE_UNKNOWN	N/A
VI_ATTR_GPIB_SRQ_STATE	0x3FFF0067UL	RO	Global	ViInt16	VI_STATE_ASSERTED VI_STATE_UNASSERTED VI_STATE_UNKNOWN	N/A
VI_ATTR_GPIB_SYS_CNTRL_STATE	0x3FFF0068UL	RW	Global	ViBoolean	VI_TRUE VI_FALSE	N/A

INTFC Resource Attribute Descriptions

Attribute Name	Attribute Value	Description
Generic INTFC Resource Attributes
VI_ATTR_INTF_NUM	0x3FFF0176UL	Board number for the given interface.
VI_ATTR_INTF_TYPE	0x3FFF0171UL	Interface type of the given session.
VI_ATTR_INTF_INST_NAME	0xBFFF00E9UL	Human-readable text describing the given interface.
VI_ATTR_SEND_END_EN	0x3FFF0016UL	Whether to assert END during the transfer of the last byte of the buffer.
VI_ATTR_TERMCHAR	0x3FFF0018UL	Termination character. When the termination character is read and VI_ATTR_TERMCHAR_EN is enabled during a read operation, the read operation terminates.
VI_ATTR_TERMCHAR_EN	0x3FFF0038UL	Flag that determines whether the read operation should terminate when a termination character is received.
VI_ATTR_TMO_VALUE	0x3FFF001AUL	Minimum timeout value to use, in milliseconds. A timeout value of VI_TMO_IMMEDIATE means that operations should never wait for the device to respond. A timeout value of VI_TMO_INFINITE disables the timeout mechanism.
VI_ATTR_DEV_STATUS_BYTE	0x3FFF0189UL	This attribute specifies the 488-style status byte of the local controller associated with this session. If this attribute is written and bit 6 (0x40) is set, this device or controller will assert a service request (SRQ) if it is defined for this interface.
VI_ATTR_WR_BUF_OPER_MODE	0x3FFF002DUL	Determines the operational mode of the write buffer. When the operational mode is set to VI_FLUSH_WHEN_FULL (default), the buffer is flushed when an END indicator is written to the buffer, or when the buffer fills up. If the operational mode is set to VI_FLUSH_ON_ACCESS, the write buffer is flushed under the same conditions, and also every time a viPrintf operation completes.
VI_ATTR_DMA_ALLOW_EN	0x3FFF001EUL	This attribute specifies whether I/O accesses should use DMA ( VI_TRUE) or Programmed I/O ( VI_FALSE). In some implementations, this attribute may have global effects even though it is documented to be a local attribute. Since this affects performance and not functionality, that behavior is acceptable.
VI_ATTR_RD_BUF_OPER_MODE	0x3FFF002AUL	Determines the operational mode of the read buffer. When the operational mode is set to VI_FLUSH_DISABLE (default), the buffer is flushed only on explicit calls to viFlush. If the operational mode is set to VI_FLUSH_ON_ACCESS, the buffer is flushed every time a viScanf operation completes.
VI_ATTR_FILE_APPEND_EN	0x3FFF0192UL	This attribute specifies whether viReadToFile will overwrite (truncate) or append when opening a file.
VI_ATTR_RD_BUF_SIZE	0x3FFF002BUL	This attribute specifies the size of the formatted I/O read buffer. The user can modify this value by calling viSetBuf().
VI_ATTR_WR_BUF_SIZE	0x3FFF002EUL	This attribute specifies the size of the formatted I/O write buffer. The user can modify this value by calling viSetBuf().
GPIB-Specific INTFC Resource Attributes
VI_ATTR_GPIB_PRIMARY_ADDR	0x3FFF0172UL	Primary address of the local GPIB controller used by the given session.
VI_ATTR_GPIB_SECONDARY_ADDR	0x3FFF0173UL	Secondary address of the local GPIB controller used by the given session.
VI_ATTR_GPIB_REN_STATE	0x3FFF0181UL	This attribute returns the current state of the GPIB REN (Remote ENable) interface line.
VI_ATTR_GPIB_ATN_STATE	0x3FFF0057UL	This attribute shows the current state of the GPIB ATN (ATtentioN) interface line.
VI_ATTR_GPIB_NDAC_STATE	0x3FFF0062UL	This attribute shows the current state of the GPIB NDAC (Not Data ACcepted) interface line.
VI_ATTR_GPIB_SRQ_STATE	0x3FFF0067UL	This attribute shows the current state of the GPIB SRQ (Service ReQuest) interface line.
VI_ATTR_GPIB_CIC_STATE	0x3FFF005EUL	This attribute shows whether the specified GPIB interface is currently CIC (controller in charge).
VI_ATTR_GPIB_SYS_CNTRL_STATE	0x3FFF0068UL	This attribute shows whether the specified GPIB interface is currently the system controller. In some implementations, this attribute may be modified only through a configuration utility. On these systems, this attribute is read only (RO).
VI_ATTR_GPIB_HS488_CBL_LEN	0x3FFF0069UL	This attribute specifies the total number of meters of GPIB cable used in the specified GPIB interface. If HS488 is not implemented, querying this attribute should return the value VI_GPIB_HS488_NIMPL. On these systems, trying to set this attribute value will return error VI_ERROR_NSUP_ATTR_STATE.
VI_ATTR_GPIB_ADDR_STATE	0x3FFF005CUL	This attribute shows whether the specified GPIB interface is currently addressed to talk or listen, or is not addressed.

INTFC Resource Events

This resource defines the following events for communication with applications, where AP = Access Privilege.

VI_EVENT_GPIB_CIC - Notification that the GPIB controller has gained or lost CIC (controller in charge) status.

Event Attribute	Attribute Value	Description	AP	Data Type	Range
VI_ATTR_EVENT_TYPE	0x3FFF4010UL	Unique logical identifier of the event.	RO	ViEventType	VI_EVENT_GPIB_CIC
VI_ATTR_GPIB_RECV_CIC_STATE	0x3FFF4193UL	Controller has become controller in charge.	RO	ViBoolean	VI_TRUE VI_FALSE

VI_EVENT_GPIB_TALK - Notification that the GPIB controller has been addressed to talk.

Event Attribute	Attribute Value	Description	AP	Data Type	Range
VI_ATTR_EVENT_TYPE	0x3FFF4010UL	Unique logical identifier of the event.	RO	ViEventType	VI_EVENT_GPIB_TALK

VI_EVENT_GPIB_LISTEN - Notification that the GPIB controller has been addressed to listen.

Event Attribute	Attribute Value	Description	AP	Data Type	Range
VI_ATTR_EVENT_TYPE	0x3FFF4010UL	Unique logical identifier of the event.	RO	ViEventType	VI_EVENT_GPIB_LISTEN

VI_EVENT_CLEAR - Notification that the GPIB controller has been sent a device clear message.

Event Attribute	Attribute Value	Description	AP	Data Type	Range
VI_ATTR_EVENT_TYPE	0x3FFF4010UL	Unique logical identifier of the event.	RO	ViEventType	VI_EVENT_CLEAR

VI_EVENT_TRIG - Notification that a trigger interrupt was received from the interface.

Event Attribute	Attribute Value	Description	AP	Data Type	Range
VI_ATTR_EVENT_TYPE	0x3FFF4010UL	Unique logical identifier of the event.	RO	ViEventType	VI_EVENT_TRIG
VI_ATTR_RECV_TRIG_ID	0x3FFF4012UL	The identifier of the triggering mechanism on which the specified trigger event was received.	RO	ViInt16	VI_TRIG_SW

VI_EVENT_IO_COMPLETION - Notification that an asynchronous operation has completed.

Event Attribute	Attribute Value	Description	AP	Data Type	Range
VI_ATTR_EVENT_TYPE	0x3FFF4010UL	Unique logical identifier of the event.	RO	ViEventType	VI_EVENT_IO_COMPLETION
VI_ATTR_STATUS	0x3FFF4025UL	Return code of the asynchronous I/O operation that has completed.	RO	ViStatus	N/A
VI_ATTR_JOB_ID	0x3FFF4006UL	Job ID of the asynchronous operation that has completed.	RO	ViJobId	N/A
VI_ATTR_BUFFER	0x3FFF4027UL	Address of buffer used in an asynchronous operation.	RO	ViBuf	N/A
VI_ATTR_RET_COUNT	32-bit: 0x3FFF4026UL 64-bit: 0x3FFF4028UL	Actual number of elements that were asynchronously transferred.	RO	ViBus Size	*
VI_ATTR_RET_COUNT_32	0x3FFF4026UL	Actual number of elements that were asynchronously transferred.	RO	ViUInt32	0 to FFFFFFFFh
VI_ATTR_RET_COUNT_64**	0x3FFF4028UL	Actual number of elements that were asynchronously transferred.	RO	ViUInt64	0 to FFFFFFFF FFFFFFFFh
VI_ATTR_OPER_NAME	0xBFFF4042UL	The name of the operation generating the event.	RO	ViString	N/A

*The data type is defined in the appropriate VPP 4.3.x framework specification.

**Defined only for operating systems that are 64-bit native.

INTFC Resource Operations

viAssertTrigger (vi, protocol)

viBufRead (vi, buf, count, retCount)

viBufWrite (vi, buf, count, retCount)

viFlush (vi, mask)

viGpibCommand (vi, buf, count, retCount)

viGpibControlATN (vi, mode)

viGpibControlREN (vi, mode)

viGpibPassControl (vi, primAddr, secAddr)

viGpibSendIFC (vi)

viPrintf (vi, writeFmt, arg1, arg2, ...)

viRead (vi, buf, count, retCount)

viReadAsync (vi, buf, count, jobId)

viReadToFile (vi, fileName, count, retCount)

viScanf (vi, readFmt, arg1, arg2, ...)

viSetBuf (vi, mask, size)

viSPrintf (vi, buf, writeFmt, arg1, arg2, ...)

viSScanf (vi, buf, readFmt, arg1, arg2, ...)

viVPrintf (vi, writeFmt, params)

viVScanf (vi, readFmt, params)

viVSPrintf (vi, buf, writeFmt, params)

viVSScanf (vi, buf, readFmt, params)

viWrite (vi, buf, count, retCount)

viWriteAsync (vi, buf, count, jobId)

viWriteFromFile (vi, fileName, count, retCount)