46.5.8 Filter Config

Table 46-9. Register Bit Attribute Legend
Symbol	Description	Symbol	Description	Symbol	Description
R	Readable bit	HC	Cleared by Hardware	(Grey cell)	Unimplemented
W	Writable bit	HS	Set by Hardware	X	Bit is unknown at Reset
K	Write to clear	S	Software settable bit	—	—

Name:	FILTERCFG
Offset:	0x214
Reset:	0x00000000
Property:	R/W

The FILTERCFG register contains the configuration of the tamper filter. The MSB of the register are used as a protection key to avoid unwanted write access.


Bit	31	30	29	28	27	26	25	24
	PROTKEY[15:8]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	23	22	21	20	19	18	17	16
	PROTKEY[7:0]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	15	14	13	12	11	10	9	8
				PERIOD[4:0]
Access				R/W	R/W	R/W	R/W	R/W
Reset				0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
						THRESH[2:0]
Access						R/W	R/W	R/W
Reset						0	0	0

Bits 31:16 – PROTKEY[15:0] Protection Key

Write protection key (0x92F5)

Bits 12:8 – PERIOD[4:0] Period

Filter period

Value	Name	Description
Encoding	FilterTimeRef bit	Approximated period if gray counter at 2 kHz
0x0	0	1 ms
0x1	1	2 ms
0x2	2	4 ms
0x3	3	8 ms
0x4	4	16 ms
0x5	5	31 ms
0x6	6	63 ms
0x7	7	125 ms
0x8	8	250 ms
0x9	9	500 ms
0xA	10	1 sec
0xB	11	2 sec
0xC	12	4 sec
0xD	13	8 sec
0xE	14	16 sec
0xF	15	32 sec
0x10	16	1 min
0x11	17	2 min
0x12	18	4 min
0x13	19	9 min
0x14	20	17 min
0x15	21	34 min
0x16	22	1 h
0x17	23	2 h
0x18	24	4.5 h
0x19	25	9 h
0x1A	26	18 h
0x1B	27	1.5 days
0x1C	28	3 days
0x1D	29	6 days
0x1E	30	12 days
0x1F	31	24 days

Bits 2:0 – THRESH[2:0] Threshold

Filter threshold

Value	Description
Encoding	Threshold
0x7	2 tamper detections
0x6	4 tamper detections
0x5	8 tamper detections
0x4	16 tamper detections
0x3	32 tamper detections
0x2	64 tamper detections
0x1	128 tamper detections
0x0	256 tamper detections