AT90LS2333-4AI Atmel, AT90LS2333-4AI Datasheet - Page 37

• 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

•
When the WDE is set (one) the Watchdog Timer is enabled, and if the WDE is cleared (zero) the Watchdog Timer function
is disabled. WDE can only be cleared if the WDTOE bit is set(one). To disable an enabled watchdog timer, the following
procedure must be followed:
1. In the same operation, write a logical one to WDTOE and WDE. A logical one must be written to WDE even though
2. Within the next four clock cycles, write a logical 0 to WDE. This disables the watchdog.
•
The WDP2, WDP1 and WDP0 bits determine the Watchdog Timer prescaling when the Watchdog Timer is enabled. The
different prescaling values and their corresponding time-out Periods are shown inTable 16. .
Table 16. Watch Dog Timer Prescale Select
Note:
Bit 3 - WDE: Watch Dog Enable
Bits 2..0 - WDP2, WDP1, WDP0: Watch Dog Timer Prescaler 2, 1 and 0
WDP2
it is set to one before the disable operation starts.
0
0
0
0
1
1
1
1
The frequency of the watchdog oscillator is voltage dependent as shown in the Electrical Characteristics section.
The WDR - Watchdog Reset - instruction should always be executed before the Watchdog Timer is enabled. This ensures that
the reset period will be in accordance with the Watchdog Timer prescale settings. If the Watchdog Timer is enabled without
reset, the watchdog timer may not start counting from zero.
WDP1
0
0
1
1
0
0
1
1
WDP0
0
1
0
1
0
1
0
1
Number of WDT Oscillator cycles
16K cycles
32K cycles
64K cycles
128K cycles
256K cycles
512K cycles
1,024K cycles
2,048K cycles
AT90S/LS2333 and AT90S/LS4433
Typical time-out
at V
47 ms
94 ms
0.19 s
0.38 s
0.75 s
CC
1.5 s
3.0 s
6.0 s
= 3.0V
Typical time-out
at V
15 ms
30 ms
60 ms
0.12 s
0,24 s
0.49 s
0.97 s
CC
1.9 s
= 5.0V
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