oDDELink Object

Description
Operation
Properties

Examples
Related
Version History & Bug list

A Processing Object that dynamically exchanges data with other ooPICs by transmitting information over an I2C network to which both ooPICs are connected.

The following table lists the size and availability of the oDDELink Object.

	Object	Size	Description	A1	A2	B1	B2	C1
	oDDELink	8 Bytes	Provides a Dynamic-Data-Exchange link over the I2C network.	x	x	x	x	x

Operation:

An oDDELink Object uses the I2C network to transfer data to and from a local Object located within the same physical ooPIC and a remote Object located in any other physical ooPIC connected to the I2C network. An oDDELink Object is required in both the Local ooPIC and the Remote ooPIC to complete a communication link over the I2C network. To create a communication link, three specifications must be made: (1) The local Object is specified by the Input and the Output properties of the local oDDELink Object (2) The Remote Object is specified with the Input and Output properties of the Remote oDDELink Object (3) The Remote oDDELink Object is specified by the Node and Location properties of the local oDDELink object (See "Using the oDDELink Object" in the ooPIC Programmers guide for more information on the 3 specifications). When the Operate property of the local oDDELink Object is set to cvTrue, it will initiate a communication link between the local oDDELink Object and the remote oDDELink Object and transfer the data. When a data transfer is successfully initiated, the values of the oValue Objects pointed to by the Input and Output properties will have been copied in the direction specified by the Direction property and the Operate property will be cleared to 0. If the network is busy or if an I2C arbitration is lost, the transmission will wait until the network is not busy and try again.

NOTE: You may not link to a system object (ooPIC.Hz1 for instance) the compiler will not allow this.

Properties:

The following table lists the properties of the oDDELink Object:

Property
Description

Sync

A value that is used to instruct the oDDELink object to synchronize its data with the remote oDDELink object's data.

Object Class: oLogic Value Range: 0 - 1

Data Type: Numeric Default Value: 0

The following table list the values of the Sync Property:

Sync Constant Description

0 cvFalse
The Value properties are not synchronizing.

1 cvTrue
The Value properties are synchronizing.

Input

A pointer to a local oValue Object whose value will be send to the remote-object.

Object Class: oValuePtrI Value Range: Any oValue Object

Data Type: Pointer Default Value: Null

Output

A pointer to a local oValue Object whose value will be updated with the remote-object's value.

Object Class: oValuePtrO Value Range: Any oValue Object

Data Type: Pointer Default Value: Null

Direction

A value that selects the direction of the data flow on the I2C network.

Object Class: oSelect0to1L Value Range: 0 - 1

Data Type: Numeric Default Value: 0

The following table list the values of the Direction Property:

Direction Constant Description

0 cvSend
Data is copied from the local Object specified by the Link property to the remote Object specified by the Node and Location properties.

1 cvReceive
Data is copied from the remote Object specified by the Node and Location properties to the local Object specified by the Link property.

Node

A value that specifies the Node address of the I2C networked ooPIC that contains the remote oDDELink object.

Object Class: oVar7 Value Range: 0 - 127

Data Type: Numeric Default Value: 0

The following table list the values of the Node Property:

Node Description

0
The oDDELink Object instance is inactive.

1 - 127
The oDDELink Object will exchange data with the ooPIC on the I2C network that has that Node address.

Location

A pointer to a remote oDDELink object instance whose Link-object's data will be exchanged.

Object Class: oVar7 Value Range: 0 - 127

Data Type: Numeric Default Value: 0

Operate

A value that selects whether or not the data is updated.

Object Class: oOperate Value Range: 0 - 1

Data Type: Numeric Default Value: 0

Operate Constant Description

0 cvOff
The Value properties are not updated.

1 cvOn
The Value properties are updated.

Transmitting

A value that indicates if the oDDELink object is currently transferring data.

Object Class: oLogic Value Range: 0 - 1

Data Type: Numeric (Read-Only) Default Value: 0

The following table lists the values of the Transmitting Property:

Transmitting Constant Description

0 cvFalse
The oDDELink Object instance is idle.

1 cvTrue
The oDDELink Object instance is transferring data.

Address

Returns a pointer to the address of the oCounter Object instance.

Object Class: oAddress Value Range: 0 - 127

Data Type: Pointer (Read Only) Default Value: Address of Object

Examples:

In the following examples, the oDataStrobe Object is used

'This program creates a Virtual 
'Circuit that sends the value of 
'V to an oDDELink Object in 
'another ooPIC.

Dim D As New oDDELink
Dim V As New oByte

Sub Main()
  ooPIC.Node = 1
  D.Input.Link(V)
  D.Node = 2
  D.Location = 41
  D.Direction = cvSend
  D.Operate = cvTrue
  Do
   If D.Transmitting = cvFalse then
     V = V + 1
     D.Sync = 1
   End If
  Loop
End Sub

'This program creates a Virtual 
'Circuit that receives the 
'value of l from an oDDELink 
'Object in another ooPIC.

Dim D As New oDDELink
Dim L As New oDio8

Sub Main()
  ooPIC.Node = 2
  D.Output.Link(L)
  D.Operate = cvTrue
  L.IOGroup = 3
  L.Direction = cvOutput
End Sub