Rainbow Electronics ATtiny2313 - Manual (Page 36)

36
ATtiny2313
2543A–AVR–08/03
Figure 16. MCU Start-up, RESET Extended Externally
External Reset An External Reset is generated by a low level on the RESET pin. Reset pulses longer
than the minimum pulse width (see Table 15) will generate a reset, even if the clock is
not running. Shorter pulses are not guaranteed to generate a reset. When the applied
signal reaches the Reset Threshold Voltage – V
RST
– on its positive edge, the delay
counter starts the MCU after the Time-out period – t
TOUT
– has expired.
Figure 17. External Reset During Operation
Brown-out Detection ATtiny2313 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
CC
level during operation by comparing it to a fixed trigger level. The trigger level for the
BOD can be selected by the BODLEVEL Fuses. The trigger level has a hysteresis to
ensure spike free Brown-out Detection. The hysteresis on the detection level should be
interpreted as V
BOT+
= V
BOT
+ V
HYST
/2 and V
BOT-
= V
BOT
- V
HYST
/2.
RESET
TIME-OUT
INTERNAL
RESET
t
TOUT
V
POT
V
RST
V
CC
CC
Table 16. BODLEVEL Fuse Coding (1)
BODLEVEL 2..0 Fuses Min V
BOT
Typ V
BOT
Max V
BOT
Units
111 BOD Disabled
110 1.8
V 101 2.7
100 4.3