NI XNET XNET LIN Schedule Entry Properties

XNET LIN Schedule Entry Properties

• Collision Resolving Schedule
• Delay
• Event Identifier
• Frames
• Name
• Name Unique to Cluster
• Node Configuration:Free Format:Data Bytes
• Schedule
• Type

Frames

Each cluster can contain an arbitrary number of frames. A frame is a single message that is exchanged on the cluster. In NI-CAN, this is equivalent to an NI-CAN message.

The basic properties of a frame are its identifier (Arbitration ID for CAN, Slot ID for FlexRay) and the payload length, which can be any value between 0 and 8 for CAN and any even value between 0 and 254 for FlexRay.

In addition, several protocol-specific properties exist. You can use the NI-XNET Database Editor to edit these properties in a protocol type-specific way.

Collision Resolving Schedule

Data Type	Direction	Required?	Default
nxDatabaseRef_t	Read/Write	No	Null

Property Class

XNET LIN Schedule Entry

Property ID

nxPropLINSchedEntry_CollisionResSched

Description

A LIN schedule that resolves a collision for this event-triggered entry.

This property applies only when the entry type is event triggered. When a collision occurs for the event-triggered entry in this schedule, the master must switch to the collision resolving schedule to transfer the unconditional frames successfully.

When the entry type is any value other than event triggered, this property returns Null (invalid).

Delay

Data Type	Direction	Required?	Default
f64	Read/Write	Yes	N/A

Property Class

XNET LIN Schedule Entry

Property ID

nxPropLINSchedEntry_Delay

Description

The time from the start of this entry (slot) to the start of the next entry. (The property uses a double value in seconds, with the fractional part used for milliseconds or microseconds.)

Event Identifier

Data Type	Direction	Required?	Default
u32	Read/Write	Yes	N/A

Property Class

XNET LIN Schedule Entry

Property ID

nxPropLINSchedEntry_EventID

Description

The event-triggered entry identifier. This identifier is unprotected (NI-XNET handles the protection).

This property applies only when the entry type is event triggered. This identifier is for the event triggered entry itself, and the first payload byte is for the protected identifier of the contained unconditional frame.

Node Configuration:Free Format:Data Bytes

Data Type	Direction	Required?	Default
u8*	Read/Write	Yes	N/A

Property Class

XNET LIN Schedule Entry

Property ID

nxPropLINSchedEntry_NC_FF_DataBytes

Description

An array of 8 bytes containing raw data for LIN node configuration.

Node configuration defines a set of services used to configure slave nodes in the cluster. Every service has a specific set of parameters coded in this byte array. In the LDF, file those parameters are stored, for example, in the node (ECU) or the frame object. NI-XNET LDF reader composes those parameters to the byte values like they are sent on the bus. The LIN specification document describes the node configuration services and the mapping of the parameters to the free format bytes.

The node configuration service is executed only if the Schedule Entry Type property is set to Node Configuration.

Caution  This property is not saved to the FIBEX file. If you write this property, save the database, and reopen it, the node configuration services are not contained in the database. Writing this property is useful only in the NI-XNET session immediately following.

Schedule

Data Type	Direction	Required?	Default
nxDatabaseRef_t	Read Only	N/A	N/A

Property Class

XNET LIN Schedule Entry

Property ID

nxPropLINSchedEntry_Sched

Description

The LIN schedule that uses this entry.

This LIN schedule is considered this entry's parent. You define the parent schedule when you create the entry object. You cannot change it afterwards.

Type

Data Type	Direction	Required?	Default
u32	Read/Write	No	Unconditional

Property Class

XNET LIN Schedule Entry

Property ID

nxPropLINSchedEntry_Type

Description

All frames that contain a payload are unconditional. The LIN schedule entry type determines the mechanism for transferring frames in this entry (slot). The values (enumeration) for this property are:

0	Unconditional: A single frame transfers in this slot.
1	Sporadic: The master transmits in this slot. The master can select from multiple frames to transmit. Only updated frames are transmitted. When more than one frame is updated, the master decides by priority which frame to send. The other updated frame remains pending and can be sent when this schedule entry is processed the following time. The order of unconditional frames in the LIN Schedule Entry Frames property (the first frame has the highest priority) determines the frame priority.
2	Event triggered: Multiple slaves can transmit an unconditional frame in this slot. The slave transmits the frame only if at least one frame signal has been updated. When a collision occurs (multiple slaves try to transmit in the same slot), this is detected and resolved using a different schedule specified in the XNET LIN Schedule Entry Collision Resolving Schedule property. The resolving schedule runs once, starting in the subsequent slot after the collision, and automatically returns to the previous schedule at the subsequent position where the collision occurred.
3	Node configuration: The schedule entry contains a node configuration service. The node configuration service is defined as raw data bytes in the XNET LIN Schedule Entry Node Configuration:Free Format:Data Bytes property.

Name

Data Type	Direction	Required?	Default
string	Read/Write	Yes	Defined in nxdbCreateObject

Property Class

XNET LIN Schedule Entry

Property ID

nxPropLINSchedEntry_Name

Description

String identifying the LIN schedule entry object.

Lowercase letters (a–z), uppercase letters (A–Z), numbers, and the underscore (_) are valid characters for the short name. The space ( ), period (.), and other special characters are not supported within the name. The short name must begin with a letter (uppercase or lowercase) or underscore, and not a number. The short name is limited to 128 characters.

A schedule entry name must be unique for all entries in the same schedule.

Name Unique to Cluster

Data Type	Direction	Required?	Default
string	Read Only	N/A	N/A

Property Class

XNET Subframe

Property ID

nxPropSubfrm_NameUniqueToCluster

Description

This property returns a subframe name unique to the cluster that contains the subframe. If the single name is not unique within the cluster, the name is ..

You can pass the name to the nxdbFindObject function to retrieve the reference to the object, while the single name is not guaranteed success in nxdbFindObject because it may be not unique in the cluster.