Rainbow Electronics ATmega163L - Manual (Page 22)

ATmega163(L)
22
Figure 24. Reset Logic
Notes: 1. Values are guidelines only. Actual values are TBD.
2. The Power-on Reset will not work unless the supply voltage has been below V
POT
(falling).
MCU Status
Register (MCUSR)
Brown-Out
Reset Circuit
BODEN
BODLEVEL
Delay Counters
CKSEL[3:0]
CK
TIMEOUT
WDRF BORF
EXTRF
PORF
DATA BUS
Clock
Generator
SPIKE
FILTER
100-500k Ω
Table 4. Reset Characteristics (V
CC
= 5.0V) (1)
Symbol Parameter Condition Min Typ Max Units
V
POT
Power-on Reset Threshold Voltage (rising) 1.0 1.4 1.8 V
Power-on Reset Threshold Voltage (falling) (2) 0.4 0.6 0.8 V
V
RST
RESET Pin Threshold Voltage - - 0.85 V
CC
V
V
BOT
Brown-out Reset Threshold Voltage (BODLEVEL = 1) 2.5 2.7 2.9
V
(BODLEVEL = 0) 3.6 4.0 4.4
Table 5. Reset Delay Selections (1)
CKSEL (2)
Start-up Time, V
CC
= 2.7V,
BODLEVEL Unprogrammed
Start-up Time, V
CC
= 4.0V,
BODLEVEL Programmed Recommended Usage (3)
0000 4.2 ms + 6 CK 5.8 ms + 6 CK Ext. Clock, fast rising power
0001 30 µs + 6 CK (4) 10 µs + 6 CK (5) Ext. Clock, BOD enabled
0010 (6) 67 ms + 6 CK 92 ms + 6 CK Int. RC Oscillator, slowly rising power
0011 4.2 ms + 6 CK 5.8 ms + 6 CK Int. RC Oscillator, fast rising power
0100 30 µs + 6 CK (4) 10 µs + 6 CK (5) Int. RC Oscillator, BOD enabled
0101 67 ms + 6 CK 92 ms + 6 CK Ext. RC Oscillator, slowly rising power
0110 4.2 ms + 6 CK 5.8 ms + 6 CK Ext. RC Oscillator, fast rising power