Advantech PCI-1680U, User Manual

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57 PCI-1680U/1682U User Manual
Chapter 4
S
oftware
R
equirements
4.6 Acceptance filtering
Acceptance code corresponds to 4 registers: ACR0, ACR1, ACR2, ACR3.Accep-
tance mask corresponds to 4 registers: AMR0, AMR1, AMR2, AMR3.ACR works with
AMR. Only when the acceptance filtering of the Standard frame or the Extended
frame is confirmed, will the filter save the data of the frame into FIFO.
For AMR bits,
„
0: the corresponding bits of ACR and CAN information frames should be the
same in order to be accepted.
„
1: the acceptance filtering function of the corresponding ACR bits is disabled
and the corresponding bits of the CAN information frame are independent of the
acceptance result.
Single mode
For Standard frame, 11 identifiers and the RTR bit correspond to ACR0, ACR1,
AMR0 and AMR1 with unused lower 4 bits of ACR1 and AMR1. Since the Standard
frame has 11 identifiers only, the first 2 bytes of the data field are also included for fil-
tering.Data1 corresponds to ACR2, AMR2; Data2 corresponds to ACR3, AMR3. If
the received Standard frame is a Remote frame and the RTR bit is 1, then only the
identifier will be used for filtering.If the received Standard frame is a data frame and
the data field is less than 2 bytes, then the missed data will not be used for filtering.
For Extended frame, 29 identifiers and the RTR bit correspond to 4 ACRs and 4
AMRs. Please note that the lower 2 bits of ACR3 and AMR3 are reserved.
„
Example of Standard frame:
In this example, Data1, Data2 and RTR are not considered and the accepted IDs
include: 0x7D7(11111010111), 0x610(11000010000), etc.
„
Example of Extended frame:
In this example, RTR is not considered and the accepted IDs include:
0x12961806(10010100101100001100000000110),
0x129639E6(10010100101100011100111100110), etc.
0 1(lower 4 bits) 2 3
ACR 11XXX010 XXXX XXXXXXXX XXXXXXXX
ACM 00111000 1111 11111111 11111111
accepted
ID(ID.10``ID.0)
11XXX010 XXX
0 1 2 3
ACR 10010100 1011000X 1100XXXX 00110XXX
ACM 00000000 00000001 00001111 00000111
accepted
ID(ID.28``ID.0)
10010100 1011000X 1100XXXX 00110XXX