Standard Message ID Filter Element

Up to 128 filter elements can be configured for 11-bit standard IDs. When accessing a Standard Message ID Filter element, its address is the Filter List Standard Start Address SIDFC.FLSSA plus the index of the filter element (0 ... 127).

Table 1. Standard Message ID Filter Element
	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
S0	SFT [1:0]		SFEC [2:0]			SFID1[10:0]																SFID2[10:0]

Bits 31:30 - SFT[1:0]: Standard Filter Type

This field defines the standard filter type.

Table 2. Standard Filter Type
Value	Name	Description
0x0	RANGE	Range filter from SFID1 to SFID2 (SFID2 >= SFID1)
0x1	DUAL	Dual ID filter for SFID1 or SFID2
0x2	CLASSIC	Classic filter: SFID1 = filter, SFID2 = mask
0x3	RES	Reserved

Bits 29:27 - SFEC[2:0]: Standard Filter Element Configuration

All enabled filter elements are used for acceptance filtering of standard frames. Acceptance filtering stops at the first matching enabled filter element or when the end of the filter list is reached. If SFEC = “100”, “101”, or “110” a match sets interrupt flag IR.HPM and, if enabled, an interrupt is generated. In this case register HPMS is updated with the status of the priority match.

Table 3. Standard Filter Element Configuration
Value	Name	Description
0x0	DISABLE	Disable filter element
0x1	STF0M	Store in Rx FIFO 0 if filter matches
0x2	STF1M	Store in Rx FIFO 1 if filter matches
0x3	REJECT	Reject ID if filter matches
0x4	PRIORITY	Set priority if filter matches.
0x5	PRIF0M	Set priority and store in FIFO 0 if filter matches.
0x6	PRIF1M	Set priority and store in FIFO 1 if filter matches.
0x7	STRXBUF	Store into Rx Buffer or as debug message, configuration of SFT[1:0] ignored.

Bits 26:16 - SFID1[10:0]: Standard Filter ID 1

First ID of standard ID filter element.

When filtering for Rx Buffers or for debug messages this field defines the ID of a standard mesage to be stored. The received identifiers must match exactly, no masking mechanism is used.
Bits 15:11 - Reserved
Bits 10:0 - SFID2[10:0]: Standard Filter ID 2

This bit field has a different meaning depending on the configuration of SFEC. 
1. SFEC = “001” ... “110”: Second ID of standard ID filter element. 
2. SFEC = “111”: Filter for Rx Buffers or for debug messages.
SFID2[10:9] decides whether the received message is stored into an Rx Buffer or treated as message A, B, or C of the debug message sequence.  00 = Store message into an Rx Buffer  01 = Debug Message A  10 = Debug Message B  11 = Debug Message C

SFID2[8:6] is used to control the filter event pins at the Extension Interface. A ‘1’ at the respective bit position enables generation of a pulse at the related filter event pin with the duration of one CLK_CAN_APB period in case the filter matches.

SFID2[5:0] defines the offset to the Rx Buffer Start Address RXBC.RBSA for storage of a matching message.