AT90LS2333-4AI Atmel, AT90LS2333-4AI Datasheet - Page 21

• 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

Figure 26. MCU Start-Up, RESET Controlled Externally
External Reset
An external reset is generated by a low level on the RESET pin. Reset pulses longer than 50 ns will generate a reset, even
if the clock is not running. Shorter pulses are not guaranteed to generate a reset.When the applied signal reaches the
Reset Threshold Voltage V
expired.
Figure 27. External Reset During Operation
Brown-Out Detection
AT90S2333/4433 has an on-chip brown-out detection (BOD) circuit for monitoring the V
power supply must be decoupled with a 47 nF to 100 nF capacitor if the BOD function is used. The BOD circuit can be
enabled/disabled by the fuse BODEN. When BODEN is enabled (BODEN programmed), and V
below the trigger level, the brown-out reset is immediately activated. When V
brown-out reset is deactivated after a delay. The delay is defined by the user in the same way as the delay of POR signal,
in Table 5. The trigger level for the BOD can be selected by the fuse BODLEVEL to be 2.7V (BODLEVEL unprogrammed),
or 4.0V (BODLEVEL programmed). The trigger level has a hysteresis of 50 mV to ensure spike free brown-out detection.
The BOD circuit will only detect a drop in V
4.0V, 7 µs for trigger level 2.7V (typical values).
INTERNAL
TIME-OUT
RESET
RESET
VCC
RST
on its positive edge, the delay timer starts the MCU after the Time-out period t
V
CC
POT
if the voltage stays below the trigger level for longer than 3 µs for trigger level
AT90S/LS2333 and AT90S/LS4433
V
RST
t
TOUT
CC
increases above the trigger level, the
CC
level during the operation. The
CC
decreases to a value
TOUT
has
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