38.5.2 RST and BOD

Table 38-16. Reset, WDT, Oscillator Start-up Timer, Power-up Timer, Brown-out Detector Specifications
Symbol	Description	Min.	Typ. ✝	Max.	Unit	Conditions
t_RST *	RESET pin pulse-width low to ensure a Reset	2.5	—	—	μs
R_{RST_UP} *	RESET pin pull-up resistor	—	35	—	kΩ
T_WDT *	Watchdog Timer time-out period	—	500	—	ms	1:512 Prescaler
T_SUT *	Power-up timer period	—	64	—	ms	SUT = `0x07`
T_OST *	Oscillator start-up timer period⁽¹⁾	—	1024	—	cycles
V_BOD	Brown-out Detect Voltage⁽²⁾	1.8 2.3 2.55 2.7	1.9 2.45 2.7 2.85	2.1 2.6 2.85 3	V V V V	BODLEVEL0 BODLEVEL1 BODLEVEL2 BODLEVEL3
V_{BOD_HYS}	Brown-out Detect hysteresis	—	44	—	mV
t_{BOD_ST}	Brown-out Detect start-up time	—	1.9	—	μs
t_{BOD_128HZ}	BOD Response Time Sampling mode @128 Hz	—	7.81	—	ms	SAMPFREQ = `0`
t_{BOD_32HZ}	BOD Response Time Sampling mode @32 Hz	—	31.25	—	ms	SAMPFREQ = `1`
t_{BOD_RST}	Brown-out Reset response time	—	3	—	μs
✝ Data in the “Typ.” column is at T_A = 25°C and V_DD = 3.0V unless otherwise specified. These parameters are for design guidance only and are not tested. * These parameters are characterized but not tested in production. Note: By design, the Oscillator Start-up Timer (T_OST) counts the first 1024 cycles, independent of frequency. To ensure these voltage tolerances, V_DD and GND must be capacitively decoupled as close to the device as possible. Values 0.1 μF and 0.01 μF are recommended in parallel.

Table 38-17. Voltage Level Monitor Threshold Specifications
Symbol	Description	Min.	Typ. ✝	Max.	Unit	Conditions
V_DET *	Voltage detection threshold	1	5	10	% of BOD threshold	VLMLVL = `0x01`
		9	15	22		VLMLVL = `0x02`
		19	25	32		VLMLVL = `0x03`
✝ Data in the “Typ.” column is at T_A = 25°C and V_DD = 3.0V unless otherwise specified. These parameters are for design guidance only and are not tested. * These parameters are characterized but not tested in production.