Bosch TTCAN - Manual (Page 25)

User’s Manual
BOSCH - 25/77 -
Revision 1.6 TTCAN
11.11.02
manual_about.fm
ID28-0 Message Identifier
ID28 - ID0
29-bit Identifier (“Extended Frame”).
ID28 - ID18 11-bit Identifier (“Standard Frame”).
Msk28-0 Identifier Mask
one
The corresponding identifier bit is used for acceptance filtering.
zero The corresponding bit in the identifier of the message object cannot inhibit
the match in the acceptance filtering.
Xtd Extended Identifier
one
The 29-bit (“extended”) Identifier will be used for this Message Object.
zero The 11-bit (“standard”) Identifier will be used for this Message Object.
MXtd Mask Extended Identifier
one
The extended identifier bit (IDE) is used for acceptance filtering.
zero The extended identifier bit (IDE) has no effect on the acceptance filtering
Note : When 11-bit (“standard”) Identifiers are used for a Message Object, the identifiers of received
Data Frames are written into bits ID28 to ID18. For acceptance filtering, only these bits together
with mask bits Msk28 to Msk18 are considered.
Dir Message Direction
one
Direction = transmit: On TxRqst, the respective Message Object is trans-
mitted 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).
zero Direction = receive: On TxRqst, a Remote Frame with the identifier of this
Message Object is transmitted. On reception of a Data Frame with match-
ing identifier, that message is stored in this Message Object.
MDir Mask Message Direction
one
The message direction bit (Dir) is used for acceptance filtering.
zero The message direction bit (Dir) has no effect on the acceptance filtering.
The Arbitration Registers ID28-0, Xtd, and Dir are used to define the identifier and type of
outgoing messages and are used (together with the mask registers Msk28-0, MXtd, and
MDir) for acceptance filtering of incoming messages. A received message is stored into the
valid Message Object with matching identifier and Direction=
receive (Data Frame) or
Direction= transmit (Remote Frame). Extended frames can be stored only in Message Objects
with Xtd = one, standard frames in Message Objects with Xtd = zero. If a received message
(Data Frame or Remote Frame) matches with more than one valid Message Object, it is stored
into that with the lowest message number. For details see chapter 4.1.3 Acceptance Filtering
of Received Messages.
EoB End of Block
one
Single Message Object or last Message Object of a FIFO Buffer Block.
zero Message Object belongs to a FIFO Buffer Block and is not the last Mes-
sage Object of that FIFO Buffer Block.
Note : This bit is used to concatenate two ore 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 chapter 4.2.2.3.
MSC2-0 Message Status Count
0-7
The actual value of the Message Status Count, read-only in active mode.
Note : The Message Status Count is status information that is generated for periodic Message Objects
in Time Triggered Communication (ISO11898-4). It has no function in Event Driven CAN Com-
munication (ISO11898-1) and for arbitrating Message Objects in TTCAN.