Rainbow Electronics ATtiny28L - Manual (Page 14)

14
ATtiny28L/V
1062E–10/01
Figure 15. Reset Logic
Note: 1. The Power-on Reset will not work unless the supply voltage has been below V
POT
(falling).
Table 4. Reset Characteristics
Symbol Parameter Min Typ Max Unit
V
POT
(1)
Power-on Reset Threshold Voltage (rising) 1.0 1.4 1.8 V
Power-on Reset Threshold Voltage (falling) 0.4 0.6 0.8 V
V
RST
RESET Pin Threshold Voltage 0.6 V
CC
V
Table 5. ATtiny28 Clock Options and Start-up Time
CKSEL3..0 Clock Source Start-up Time at 2.7V
1111 External Crystal/Ceramic Resonator (1) 1K CK
1110 External Crystal/Ceramic Resonator (1) 4.2 ms + 1K CK
1101 External Crystal/Ceramic Resonator (1) 67 ms + 1K CK
1100 External Crystal/Ceramic Resonator 16K CK
1011 External Crystal/Ceramic Resonator 4.2 ms + 16K CK
1010 External Crystal/Ceramic Resonator 67 ms + 16K CK
1001 External Low-frequency Crystal 67 ms + 1K CK
1000 External Low-frequency Crystal 67 ms + 32K CK
0111 External RC Oscillator 6 CK
0110 External RC Oscillator 4.2 ms + 6 CK
0101 External RC Oscillator 67 ms + 6 CK
Power-on
Reset Circuit
Reset Circuit
Watchdog
Timer
On-chip
RC Oscillator
VCC
RESET
100 - 500K
Delay Counters
CK
CKSEL[3..0]
S
R
Q
Full
INTERNAL RESET
COUNTER RESET
MCU Control and Status
Register (MCUCS)
PORF
EXTRF WDRF
DATA BUS