SH7205 Datasheet, PDF (975/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 20 Controller Area Network (RCAN-TL1)
DLC[3:0] (Data Length Code): These bits encode the number of data bytes from 0,1, 2, … 8 that
will be transmitted in a data frame. Please note that when a remote frame request is transmitted the
DLC value to be used must be the same as the DLC of the data frame that is requested.
DLC[3] DLC[2] DLC[1] DLC[0] Description
0
0
0
0
Data Length = 0 bytes (Initial value)
0
0
0
1
Data Length = 1 byte
0
0
1
0
Data Length = 2 bytes
0
0
1
1
Data Length = 3 bytes
0
1
0
0
Data Length = 4 bytes
0
1
0
1
Data Length = 5 bytes
0
1
1
0
Data Length = 6 bytes
0
1
1
1
Data Length = 7 bytes
1
x
x
x
Data Length = 8 bytes
(2) Local Acceptance Filter Mask (LAFM)
This area is used as Local Acceptance Filter Mask (LAFM) for receive boxes.
LAFM: When MBC is set to 001, 010, 011(Bin), this field is used as LAFM Field. It allows a
Mailbox to accept more than one identifier. The LAFM is comprised of two 16-bit read/write
areas as follows.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
H'104 + N*32
IDE_
LAFM
0
0
STDID_LAFM[10:0]
EXTID_
LAFM[17:16]
Word/LW
H'106 + N*32
EXTID_LAFM[15:0]
Word
LAFM Field
Figure 20.4 Acceptance filter
If a bit is set in the LAFM, then the corresponding bit of a received CAN identifier is ignored
when the RCAN-TL1 searches a Mailbox with the matching CAN identifier. If the bit is cleared,
then the corresponding bit of a received CAN identifier must match to the STDID/IDE/EXTID set
in the mailbox to be stored. The structure of the LAFM is same as the message control in a
Mailbox. If this function is not required, it must be filled with ‘0’.
Important: RCAN-TL1 starts to find a matching identifier from Mailbox-31 down to Mailbox-0.
As soon as RCAN-TL1 finds one matching, it stops the search. The message will be stored or not
depending on the NMC and RXPR/RFPR flags. This means that, even using LAFM, a received
message can only be stored into 1 Mailbox.
Rev. 1.00 Mar. 25, 2008 Page 943 of 1868
REJ09B0372-0100