Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
562
/
631
Figure 25-9 Filter bit width setting-register organization
Variable bit width
The bit width of each filter bank can be independently configured. Each filter bank can be configured to be one 32-
bit filter: including STDID[10:0], EXTID[17:0], IDE and RTRQ bits; or two 16-bit filters,:including STDID[10:0],
IDE, RTRQ and EXTID[17:15] bits, see Figure 25-9. In addition, the filter can be configured in two different modes,
namely, the mask mode and the identifier list mode.
Mask mode
The filter ID is used to store the identifier format, and the filter MASK is used to indicate which bits must be checked
and which bits can be ignored.
32 bit Mask Mode(CAN_FS1.FSCx = 1;CAN_FM1.FBx = 0)
FBC[31:21]
FBC[20:3]
STDID[10:0]/EXTID[28:18]
EXTID[17:0]
IDE
RTR
0
filter ID
filter Mask
USER ID
FBC2
FBC1
FBC0
FBC[31:21]
FBC2
FBC2
FBC2
FBC[20:3]
FiR1 Register
FiR2 Register
One
filter
32 bit List Mode(CAN_FS1.FSCx = 1;CAN_FM1.FBx = 1)
FBC[31:21]
FBC[20:3]
STDID[10:0]/EXTID[28:18]
EXTID[17:0]
IDE
RTR
0
filter ID
filter ID
USER ID
FBC2
FBC1
FBC0
FBC[31:21]
FBC2
FBC2
FBC2
FBC[20:3]
FiR1 Register
FiR2 Register
Two
filters
16 bit Mask Mode(CAN_FS1.FSCx = 0;CAN_FM1.FBx = 0)
FBC[15:5]
STDID[10:0]
IDE
RTR
EXTID[17:15]
filter ID
USER ID
FBC4
FBC3
FBC[2:0]
FBC[31:21]
filter MASK
FBC20
FBC19
FBC[18:16]
FBC[15:5]
filter ID
FBC4
FBC3
FBC[2:0]
FBC[31:21]
filter MASK
FBC20
FBC19
FBC[18:16]
Two
filters
16 bit List Mode(CAN_FS1.FSCx = 0;CAN_FM1.FBx = 1)
FBC[15:5]
STDID[10:0]
IDE
RTR
EXTID[17:15]
filter ID
USER ID
FBC4
FBC3
FBC[2:0]
FBC[31:21]
filter ID
FBC20
FBC19
FBC[18:16]
FBC[15:5]
filter ID
FBC4
FBC3
FBC[2:0]
FBC[31:21]
filter ID
FBC20
FBC19
FBC[18:16]
Four
filters