Information

An additional memory area, that starts at 0xE0 and may extend up to 0x2DC (normally
occupied by MBs 6 up to 37) depending on the CTRL2[RFFN] field setting, contains the
ID Filter Table (configurable from 8 to 128 table elements) that specifies filtering criteria
for accepting frames into the FIFO.
Out of reset, the ID Filter Table flexible memory area defaults to 0xE0 and only extends
to 0xFC, which corresponds to MBs 6 to 7 for RFFN=0, for backward compatibility with
previous versions of FlexCAN.
The following shows the Rx FIFO data structure.
Table 42-112. Rx FIFO Structure
31 28 24 23 22 21 20 19 18 17 16 15 8 7 0
0x80 SRR IDE RTR DLC TIME STAMP
0x84 ID Standard ID Extended
0x88 Data Byte 0 Data Byte 1 Data Byte 2 Data Byte 3
0x8C Data Byte 4 Data Byte 5 Data Byte 6 Data Byte 7
0x90
to
0xDC
Reserved
0xE0 ID Filter Table Element 0
0xE4 ID Filter Table Element 1
0xE8
to
0x2D4
ID Filter Table Elements 2 to 125
0x2D8 ID Filter Table Element 126
0x2DC ID Filter Table Element 127
= Unimplemented or Reserved
Each ID Filter Table Element occupies an entire 32-bit word and can be compound by
one, two or four Identifier Acceptance Filters (IDAF) depending on the MCR[IDAM]
field setting. The following figures show the IDAF indexation.
The following figures show the three different formats of the ID table elements. Note that
all elements of the table must have the same format. See Rx FIFO for more information.
Table 42-113. ID Table structure
Format
31 30 29 24 23 16 15 14 13 8 7 1 0
A RTR IDE
RXIDA
(Standard = 29-19, Extended = 29-1)
Table continues on the next page...
Chapter 42 CAN (FlexCAN)
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 1125