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Rev.1.10 Jul 01, 2005 page 219 of 318
REJ09B0124-0110
M16C/6N Group (M16C/6NK, M16C/6NM) 18. CAN Module
Under development
This document is under development and its contents are subject to change.
18.10 Acceptance Filter Support Unit (ASU)
The acceptance filter support unit has a function to judge valid/invalid of a received ID through table search.
The IDs to receive are registered in the data table; a received ID is stored in the CiAFS register ( i = 0, 1),
and table search is performed with a decoded received ID. The acceptance filter support unit can be used
for the IDs of the standard frame only.
The acceptance filter support unit is valid in the following cases.
• When the ID to receive cannot be masked by the acceptance filter.
(Example) IDs to receive: 078h, 087h, 111h
• When there are too many IDs to receive; it would take too much time to filter them by software.
Figure 18.18 shows the write and read of the CiAFS register in word access.
Figure 18.18 Write/read of CiAFS Register in Word Access
b15
b0
b8 b7
When read
SID10 SID9 SID8 SID7 SID6 SID5 SID4 SID3
SID10 SID9 SID8 SID7 SID6 SID5 SID4 SID3 SID2 SID1 SID0
When write
3/8 Decoder
242h
242h
Addresses
CAN0
244h
244h
CAN1
b15
b0
b8 b7