RST and BOD

Table 1. 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. Notes: 1.By design, the Oscillator Start-up Timer (T_OST) counts the first 1024 cycles, independent of frequency. 2.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 2. 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.