STR720 datasheet(229/401 Pages) STMICROELECTRONICS

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Dir

Message Direction

1: Direction = transmit: On TxRqst, the respective Message Object is

transmitted as a Data Frame. On reception of a Remote Frame with

matching identifier, the TxRqst bit of this Message Object is set (if RmtEn =

one).

0: Direction = receive: On TxRqst, a Remote Frame with the identifier of

this Message Object is transmitted. On reception of a Data Frame with

matching identifier, that message is stored in this Message Object.

MDir

Mask Message Direction

1: The message direction bit (Dir) is used for acceptance filtering.

0: The message direction bit (Dir) has no effect on the acceptance filtering.

EoB

End of Buffer

1: Single Message Object or last Message Object of a FIFO Buffer.

0: Message Object belongs to a FIFO Buffer and is not the last

Message Object of that FIFO Buffer.

Note

This bit is used to concatenate two or more Message Objects (up

to 32) to build a FIFO Buffer. For single Message Objects (not

belonging to a FIFO Buffer), this bit must always be set to one.

For details on the concatenation of Message Objects see Section

“Configuring a FIFO Buffer”.

NewDat

New Data

1: The Message Handler or the application software has written new data

into the data portion of this Message Object.

0: No new data has been written into the data portion of this Message

Object by the Message Handler since last time this flag was cleared by the

application software.

MsgLst

Message Lost (only valid for Message Objects with direction = receive)

1: The Message Handler stored a new message into this object when

NewDat was still set, the CPU has lost a message.

0: No message lost since last time this bit was reset by the CPU.

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