Atmel STK200, Manual

Page: 25 / 40

STK200 Starter Kit 8-1
Section 8
Brown-Out Detector
The brown-out detector circuit is used to detect voltage drops. If a short glitch occurs in
the power, this circuit ensures that the processor resets properly rather than operating
randomly.
The brown-out detector must be set to the same voltage as the circuit voltage, V
CC
—
3.3V or 5V. For 3.3V operation, jumper JP2 must be removed (jumper open) and for 5V
operation it must be closed.
These values are approximate and may vary with temperature and other factors.
If the brown-out detector voltage is set to 5V and V
CC
is set to 3.3V, then the brown-out
circuit will operate continuously and the device will be held in permanent reset. JP1 and
JP2 must be set to the same voltage, which is always 1 open and 1 closed.
Voltage Operating Voltage Hysteresis
5 Volts 4.5 Volts 200 mV
3.3 Volts 2.9 Volts 200 mV
Voltage JP1 JP2
5 Volts Open Closed
3.3 Volts Closed Open