AT90LS2343 ATMEL [ATMEL Corporation], AT90LS2343 Datasheet - Page 21

• Manufacturer Part Number: AT90LS2343
• Description: 8-Bit Microcontroller with 2K Bytes of In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Power-on Reset
1004D–09/01
Table 4. Reset Characteristics (V
Note:
Table 5. Reset Characteristics (V
Note:
The AT90S2323/2343 is designed for use in systems where it can operate from the
internal RC oscillator (AT90S/LS2343), on-chip oscillator (AT90S/LS2323), or in appli-
cations where a clock signal is provided by an external clock source. After V
reached V
is provided by an external clock source, the clock must not be applied until V
reached the minimum voltage defined for the applied frequency.
For AT90S2323, the user can select the start-up time according to typical oscillator
start-up. The number of WDT oscillator cycles used for each time-out is shown in
Table 6. For AT90S2343, the start-up time is one Watchdog cycle only. The frequency
of the Watchdog oscillator is voltage-dependent as shown in “Typical Characteristics” on
page 49.
Table 6. Number of Watchdog Oscillator Cycles
Symbol
V
V
t
t
t
Symbol
V
V
t
t
t
FSTRT
Programmed
Unprogrammed
TOUT
TOUT
TOUT
TOUT
TOUT
TOUT
POT
RST
POT
RST
(1)
(1)
1. The Power-on Reset will not work unless the supply voltage has been below V
1. The Power-on Reset will not work unless the supply voltage has been below V
POT
(falling).
(falling).
Parameter
Power-on Reset Threshold Voltage, rising
Power-on Reset Threshold Voltage, falling
RESET Pin Threshold Voltage
Reset Delay Time-out Period AT90S/LS2323
FSTRT Programmed
Reset Delay Time-out Period AT90S/LS2323
FSTRT Unprogrammed
Reset Delay Time-out Period AT90S/LS2343
Parameter
Power-on Reset Threshold Voltage, rising
Power-on Reset Threshold Voltage, falling
RESET Pin Threshold Voltage
Reset Delay Time-out Period AT90S/LS2323
FSTRT Programmed
Reset Delay Time-out Period AT90S/LS2323
FSTRT Unprogrammed
Reset Delay Time-out Period AT90S/LS2343
, the device will start after the time t
Time-out at V
CC
CC
16.0 ms
1.1 ms
= 5.0V)
= 3.0V)
CC
= 5V
TOUT
AT90S/LS2323/2343
(see Figure 25). If the clock signal
11.0
11.0
Min
22.0
22.0
Min
1.0
0.4
1.0
1.0
0.4
2.0
Number of WDT Cycles
0.6 V
0.6 V
16.0
16.0
32.0
32.0
Typ
Typ
1.4
0.6
1.1
1.4
0.6
2.2
16K
CC
CC
1K
Max
21.0
21.0
Max
42.0
42.0
1.8
0.8
1.2
1.8
0.8
2.4
CC
CC
Units
Units
ms
ms
ms
ms
µs
µs
V
V
V
V
V
V
has
has
POT
POT
21