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
tRST * RESET pin pulse-width low to ensure a Reset 2.5 — — μs
RRST_UP * RESET pin pull-up resistor — 35 — kΩ
TWDT * Watchdog Timer time-out period — 500 — ms 1:512 Prescaler
TSUT * Power-up timer period — 64 — ms SUT = 0x07
TOST * Oscillator start-up timer period(1) — 1024 — cycles
VBOD 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
VBOD_HYS Brown-out Detect hysteresis — 44 — mV
tBOD_ST Brown-out Detect start-up time — 1.9 — μs
tBOD_128HZ BOD Response Time Sampling mode @128 Hz — 7.81 — ms SAMPFREQ = 0
tBOD_32HZ BOD Response Time Sampling mode @32 Hz — 31.25 — ms SAMPFREQ = 1
tBOD_RST Brown-out Reset response time — 3 — μs

✝ Data in the “Typ.” column is at TA = 25°C and VDD = 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:
  1. By design, the Oscillator Start-up Timer (TOST) counts the first 1024 cycles, independent of frequency.
  2. To ensure these voltage tolerances, VDD 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
VDET * 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 TA = 25°C and VDD = 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.