AT90LS2333-4AI Atmel, AT90LS2333-4AI Datasheet - Page 20

• Manufacturer Part Number: AT90LS2333-4AI
• Description: IC MCU 2K 4MHZ A/D LV IT 32TQFP
• Manufacturer: Atmel
• Series: AVR® 90LSr

Specifications of AT90LS2333-4AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 20
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 6 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFP, 32-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Table 5. Reset Delay Selections
Notes:
This table shows the start-up times from reset. From sleep, only the clock counting part of the start-up time is used. The
watchdog oscillator is used for timing the real-time part of the start-up time. The number WDT oscillator cycles used for
each time-out is shown in Table 6.
Table 6. Number of Watchdog Oscillator Cycles
The frequency of the watchdog oscillator is voltage dependent as shown in the Electrical Characteristics section.
Power-On Reset
A Power-On Reset (POR) pulse is generated by an on-chip detection circuit. The detection level is nominally 2.2V. The
POR is activated whenever V
well as detect a failure in supply voltage.
The Power-On Reset (POR) circuit ensures that the device is reset from power-on. Reaching the power-on reset threshold
voltage invokes a delay counter, which determines the delay, for which the device is kept in RESET after V
time-out period of the delay counter is a combination of internal RC oscillator cycles and external oscillator cycles, and it
can be defined by the user through the CKSEL fuses. The eight different selections for the delay period are presented in
Table 5. The RESET signal is activated again, without any delay, when the V
Figure 25. MCU Start-Up, RESET Tied to VCC.
20
Time-out
4.0 ms (at V
64 ms (at V
CKSEL [2:0]
000
001
010
011
100
101
110
111
1. Or external power-on reset.
cc
AT90S/LS2333 and AT90S/LS4433
cc
=5.0V)
=5.0V)
Start-Up Time, t
INTERNAL
TIME-OUT
RESET
RESET
256 ms + 16K CK
16 ms + 16K CK
256 ms + 1K CK
16 ms + 1K CK
VCC
16 ms + 6 CK
16K CK
1K CK
CC
6 CK
TOUT
is below the detection level. The POR circuit can be used to trigger the start-up reset, as
at V
CC
= 2.7V
V
V
POT
RST
t
TOUT
Start-Up Time, t
64 ms + 16K CK
4 ms + 16K CK
64 ms + 1K CK
4 ms + 1K CK
4 ms + 6 CK
Number of cycles
4K
64K
16K CK
1K CK
6 CK
TOUT
at V
CC
CC
= 5.0V
decreases below detection level.
External Clock, slowly rising power
External Clock, BOD enabled
Crystal Oscillator
Crystal Oscillator, fast rising power
Crystal Oscillator, BOD enabled
Ceramic Resonator
Ceramic Resonator, fast rising power
Ceramic Resonator, BOD enabled
Recommended Usage
CC
(1)
rise. The
(1)
(1)