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R01UH0336EJ0102 Rev.1.02
Page 1113 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 20 CAN Controller (FCN)
Caution
If the transmit history list is in the overflow condition
(FCNnCMTGTX.FCNnCMTGTVFF is set), reading the transmit history list
contents is still possible, until the history list is empty (indicated by
FCNnCMTGTX.FCNnCMTGSSPM flag set). Nevertheless, the transmit history
list remains in the overflow condition until FCNnCMTGTVFF is cleared by
software. If FCNnCMTGTVFF is not cleared, the
FCNnCMTGTX.FCNnCMTGSSPM flag is not updated (cleared) upon
successful transmission of a new message. This may lead to the situation, that
FCNnCMTGSSPM indicates an empty transmit history list, although a
successful transmission has taken place, while the history list is in the overflow
state (FCNnCMTGTVFF and FCNnCMTGSSPM are set).
Figure 20-9
Transmit History List
1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
2
3
4
5
6
7
0
0
0
0
LOSSLT
LOSSLT
LOSSLT
LOSSLT
Message buffer 7
Message buffer 2
Message buffer 9
Message buffer 6
Message buffer 4
Message buffer 3
Message buffer 7
Transmit history list (THL)
Transmit history list (THL)
TGSSPT
TGSSPT
TGSSPT
TGSSPT
Transmit history list (THL)
Transmit history list (THL)
Message buffer 5
Message buffer 8
Message buffer 4
Message buffer 3
Message buffer 7
Message buffer 10
Message buffer 6
Message buffer 5
Message buffer 8
Message buffer 4
Message buffer 3
Message buffer 7
Message buffer 14
Message buffer 6
TGTVFF = 1 denoted that LOSSLT equals TGSSPT - 1 while message buffer number stored to element indicated by LOSSLT - 1.
Note 1. In the above diagram, the following abbreviations are used.
- LOSSLT = Last out-message pointer FCNnCMLOSTR.FCNnCMLOSSLT[7:0]
- TGSSPT = Transmit history list get pointer FCNnCMTGTX.FCNnCMTGSSPT[7:0]
- TGTVFF = Transmit history list overflow flag FCNnCMTGTX.FCNnCMTGTVFF
Note 2. When the message buffer where the FCNnMmCTL.FCNnMmNHMF flag has been set,
the message buffer number indicated by LOSSLT differs from that written in THL.
Event:
- CPU confirms transmit completion of
message buffer 6, 9, and 2
- Transmit completion of
message buffers 3, and 4.
Event:
- Message buffers 11, 13, and 14
complete
transmission
- Overflow situation occurs.
Event:
- Message buffers 8, 5, 6, and 10 complete transmission
- THL is full.
- TGTVFF is set.