Datasheet

42
8024A–AVR–04/08
ATmega8HVA/16HVA
Figure 11-1. Reset Logic
11.2.1 Power-on Reset and Charger Connect
The Voltage Regulator will not start up until the Charger Detect module has enabled the Voltage
Regulator. Before this happens the chip will be in Power-off mode and only the Charger Detect
module is enabled. In order for the Charger Detect module to enable the Voltage Regulator, the
voltage at the BATT pin must exceed the Power-On Threshold, V
POT
. When the voltage at the
BATT pin exceeds V
POT
, the Voltage Regulator starts up and the chip enters RESET mode, refer
to Figure 11-2 on page 43. When the Delay Counter times out, the chip will enter Active mode.
See Figure 10-1 on page 35.
MCU Status
Register (MCUSR)
Reset Circuit
Delay Counters
CK
TIMEOUT
WDRF
EXTRF
PORF
DATA BUS
Clock
Generator
SPIKE
FILTER
Pull-up Resistor
BODRF
Ultra Low Power
RC Oscillator
SUT[2:0]
Power-on
Reset
Circuit/
Charger
Detect
Watchdog
Timer
RESET
/dW
V
FET
BATT
POR
V
REG
COUNTER RESET
Brown-out
Detection
V
REG
debugWIRE
OCDRF