ST ST10F276E - Page 435

DocID13284 Rev 2 435/564
UM0404 CAN modules
The Arbitration Registers are used for acceptance filtering of incoming messages and to
define the identifier of outgoing 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. For identifier matching, the
corresponding mask has to be considered. If the identifier of 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 Table 21.9: CAN application on
page 444.
IFx message control register
CAN1IF1MC (EF1Ch) XBUS Reset Value: 0000h
CAN2IF1MC (EE1Ch) XBUS Reset Value: 0000h
CAN1IF2MC (EF4Ch) XBUS Reset Value: 0000h
CAN2IF2MC (EE4Ch) XBUS Reset Value: 0000h
Xtd
Extended Identifier
’0’: The standard Identifier (11 bit) will be used for this Message Object.
’1’: The extended Identifier (29 bit) will be used for this Message Object.
MsgVal
Message Valid
The CPU must reset the MsgVal bit of all unused Messages Objects during the
initialization before it resets bit Init in the CAN Control Register. This bit must be
reset if the message is no longer required, or if the identifier, the control bits Xtd, Dir
or the Data Length Code DLC(3:0) are modified.
’0’: The Message Object is ignored by the Message Handler.
’1’: The Message Object is configured and should be considered by the Message
Handler.
Bit Function
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
NewDat MsgLst IntPnd UMask TxIE RxIE RmtEn TxRqst EoB - DLC(3:0)
RW RW RW RW RW RW RW RW RW RW
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
NewDat MsgLst IntPnd UMask TxIE RxIE RmtEn TxRqst EoB - DLC(3:0)
RW RW RW RW RW RW RW RW RW RW