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CHAPTER 16 CAN controller
16.6
Precautions when Using CAN Controller
Use of the CAN Controller requires the following cautions.
■
Caution for disabling message buffers by BVAL bits
The use of BVAL bits may affect malfunction of CAN Controller when messages buffers are set disabled
while CAN Controller is participating in CAN communication (the read value of the CSR: HALT bit is 0
and CAN Controller is ready to transmit messages). This section shows the work around of this
malfunction.
●
Condition
When following two conditions occur at the same time, the CAN Controller will not perform to transmit
messages normally.
•
CAN Controller is participating in the CAN communication. (i.e. The read value of the CSR: HALT bit
is 0 and CAN Controller is ready to transmit messages)
•
Message buffers are read when BVAL bits disable the message buffers.
●
Work around
Operation for suppressing transmission request
Do not use BVAL bit for suppressing transmission request, use TCAN bit instead of it.
Operation for composing transmission message
For composing a transmission message, it is necessary to disable the message buffer by BVAL bit to
change contents of ID and IDE registers. In this case, BVAL bit should reset (BVAL=0) after checking
if TREQ bit is 0 or after completion of the previous message transmission (TC=1).
In case a buffer needs to be disabled, ensure that no transmission request is pending (if it was requested
before)! Therefore, do not reset BVALx-Bit before testing, if a transmission is ongoing:
a) Cancel the transmission request (TCANx=1;), if necessary
b) Wait for the transmission completion (while (TREQx==1);) by polling or interrupt.
Only after that the transmission buffer can be disabled (BVALx=0;).
Note:
Note for case a), if transmission of that buffer has already started, canceling the request is ignored and
disabling the buffer is delayed until the end of the transmission.
Содержание F2MC-16LX Series
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Страница 676: ...658 APPENDIX Table A 9 3 Bit Operation Instruction Map first byte 6CH ...
Страница 677: ...659 APPENDIX A Instructions Table A 9 4 Character String Operation Instruction Map first byte 6EH ...
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Страница 680: ...662 APPENDIX Table A 9 7 ea Instruction 2 first byte 71H ...
Страница 681: ...663 APPENDIX A Instructions Table A 9 8 ea Instruction 3 first byte 72H ...
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Страница 683: ...665 APPENDIX A Instructions Table A 9 10 ea Instruction 5 first byte 74H ...
Страница 684: ...666 APPENDIX Table A 9 11 ea Instruction 6 first byte 75H ...
Страница 685: ...667 APPENDIX A Instructions Table A 9 12 ea Instruction 7 first byte 76H ...
Страница 686: ...668 APPENDIX Table A 9 13 ea Instruction 8 first byte 77H ...
Страница 687: ...669 APPENDIX A Instructions Table A 9 14 ea Instruction 9 first byte 78H ...
Страница 688: ...670 APPENDIX Table A 9 15 MOVEA RWi ea Instruction first byte 79H ...
Страница 689: ...671 APPENDIX A Instructions Table A 9 16 MOV Ri ea Instruction first byte 7AH ...
Страница 690: ...672 APPENDIX Table A 9 17 MOVW RWi ea Instruction first byte 7BH ...
Страница 691: ...673 APPENDIX A Instructions Table A 9 18 MOV ea Ri Instruction first byte 7CH ...
Страница 692: ...674 APPENDIX Table A 9 19 MOVW ea Rwi Instruction first byte 7DH ...
Страница 693: ...675 APPENDIX A Instructions Table A 9 20 XCH Ri ea Instruction first byte 7EH ...
Страница 694: ...676 APPENDIX Table A 9 21 XCHW RWi ea Instruction first byte 7FH ...
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