Hi,
in section "21.12.5 Changing a Transmi Object" of Technical Reference Manual (spruhm 9 C - Revised December 2016) there is the following statement:
"The CPU can write the whole message
(Arbitration,
Control, and Data) into the Interface register. The bits [23:16] of the Command register can be set to 0xB7
for the transfer of the whole message object content into the message object. Neither MsgVal nor TxRqst
have to be reset before this operation."
The key sentence is "NEITHER MsgVal NOR TxRqst HAVE TO BE RESET BEFORE THIS OPERATION."
This means that the whole content of Arbitration, Control and Data registers can be changed without resetting MsgVal.
However in "Table 21-31. CAN_IF1ARB Register Field Descriptions", raw bit 31 MsgVal, column Description there is the following statement:
"This bit must also be reset before the identifier
ID[28:0], the control bits Xtd, Dir or DLC[3:0] are modified, or if the
messages object is no longer required."
This means that some bits of Arbitration (ID, Xtd, Dir) and Control (DLC) registers can be changed only after resetting MsgVal.
So the question is: Arbitration and Control registers can be changed with MsgVal = 1 or not?
Regards,
Demis
