CAN modules UM0404
440/564 DocID13284 Rev 2
MDir
Mask Message Direction
’0’: The message direction bit (Dir) has no effect on the acceptance filtering.
’1’: The message direction bit (Dir) is used for acceptance filtering.
The Arbitration Registers ID(28:0), Xtd, and Dir are used to define the identifier and
type of outgoing messages and are used (together with the mask registers
Msk(28:0), 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 Acceptance filtering of
received messages on page 447.
EoB
End of Buffer
’0’: Message Object belongs to a FIFO Buffer and is not the last Message Object of
that FIFO Buffer.
’1’: Single Message Object or last Message Object of a FIFO Buffer.
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 Section 21.9.7: Configuration of a FIFO buffer on page 449.
NewDat
New Data
’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 CPU.
’1’: The Message Handler or the CPU has written new data into the data portion of
this Message Object.
MsgLst
Message Lost (only valid for Message Objects with direction = receive)
’0’: No message lost since last time this bit was reset by the CPU.
’1’: The Message Handler stored a new message into this object when NewDat was
still set, the CPU has lost a message.
RxIE
Receive Interrupt Enable
’0’: IntPnd will be left unchanged after a successful reception of a frame.
’1’: IntPnd will be set after a successful reception of a frame.
TxIE
Transmit Interrupt Enable
’0’: IntPnd
will be
left unchanged after the successful transmission of a frame.
’1’: IntPnd will be set after a successful transmission of a frame.
IntPnd
Interrupt Pending
’0’: This message object is not the source of an interrupt.
’1’: This message object is the source of an interrupt. The Interrupt Identifier in the
Interrupt Register will point to this message object if there is no other interrupt
source with higher priority.
RmtEn
Remote Enable
’0’: At the reception of a Remote Frame, TxRqst is left unchanged.
’1’: At the reception of a Remote Frame, TxRqst is set.
Bit Function
To Next Page
Loading...
