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GD32A50x User Manual
605
of the FIFO which is the oldest message that has been received but not yet read by the CPU.
The RAM region 0x90-0xDC is reserved for internal use of the FIFO.
When RFEN bit in CAN_CTL0 register is 1, the RAM space which normally occupied by
mailbox 6
–31 with 8 byte payload is used for the ID filter table (configurable for 8 to up to 104
table elements) for receiving frames matching process into the FIFO. The ID filter table only
contains 8 elements from FDES4 to FDES11 by default.
Table 23-6.
Rx FIFO descriptor
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FDES0
IDFMN[8:0]
SR
R
IDE
RT
R
DLC[3:0]
TIMESTAMP[15:0]
FDES1
Reserved
ID_STD[10:0]
ID_EXD[17:0]
FDES2
DATA_0[7:0]
DATA_1[7:0]
DATA_2[7:0]
DATA_3[7:0]
FDES3
DATA_4[7:0]
DATA_5[7:0]
DATA_6[7:0]
DATA_7[7:0]
0x90
-
0xDC
Reserved
FDES4
ID filter table element 0
…
…
FDES1
07
ID filter table element 103
FDES0: Rx FIFO descriptor word 0
Address offset: 0x80
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
IDFMN[8:0]
SRR
IDE
RTR
DLC[3:0]
r
r
r
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TIMESTAMP[15:0]
r
Bits
Fields
Descriptions
31:23
IDFMN[8:0]
Identifier filter matching number
This bit field indicates which ID filter table element matches the received message
that is in the output of the Rx FIFO.
22
SRR
Substitute remote request
This bit is only used in extended format. It will be stored with the value received on
the CAN bus.
21
IDE
ID extended bit
This bit specifies whether the frame is standard or extended format.
0: Frame format is standard.