Fujitsu FR81S User Manual
CHAPTER 41: CAN
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: CAN
FUJITSU SEMICONDUCTOR CONFIDENTIAL
71
5.3.3. Data Frame Reception
Data frame reception is shown.
CAN controller transfers and stores the reception message from the shift register to message RAM of the
message object that matched the acceptance filter. This stored data not only contains data bytes but also all
arbitration fields and data length codes. This operation will be performed even if the IFx mask register is set
as a mask (stored in order to hold the ID and data bytes).
The NewDat bit will be set to "1" when a new data is received. Reset the NewDat bit to "0" when a message
object is read by the CPU. If the NewDat bit is already set to "1" when the message is received, the previous
data will be treated as lost and the MsgLst bit will be set to "1".
If the RxIE bit is set to "1", the IntPnd bit of the CAN interrupt pending register (INTPND) will be set to
"1" when a message buffer is received. The TxRqst bit of the message object will be cleared to "0" at this
time. This operation is performed to prevent a transmission process from starting when a request data frame
is received while the remote frame transmission process is in progress.
MB91520 Series
MN705-00010-1v0-E
1764