AT90LS4433-4AC Atmel, AT90LS4433-4AC Datasheet - Page 32

• Manufacturer Part Number: AT90LS4433-4AC
• Description: IC MCU 4K 4MHZ A/D LV 32TQFP
• Manufacturer: Atmel
• Series: AVR® 90LSr

Specifications of AT90LS4433-4AC

• 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: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 6 V
• Data Converters: A/D 6x10b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 32-TQFP, 32-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Idle Mode
Power-down Mode
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AT90S/LS4433
When the SM bit is cleared (zero), the SLEEP instruction forces the MCU into the Idle
mode stopping the CPU but allowing Timer/Counters, Watchdog and the interrupt sys-
tem to continue operating. This enables the MCU to wake up from external triggered
interrupts as well as internal ones like Timer Overflow interrupt and Watchdog Reset. If
wake-up from the Analog Comparator interrupt is not required, the Analog Comparator
can be powered down by setting the ACD bit in the Analog Comparator Control and Sta-
tus Register (ACSR). This will reduce power consumption in Idle mode.
When the SM bit is set (one), the SLEEP instruction forces the MCU into the Power-
down mode. In this mode, the External Oscillator is stopped while the external interrupts
and the Watchdog (if enabled) continue operating. Only an External Reset, a Watchdog
Reset (if enabled) or an external level interrupt can wake up the MCU.
Note that if a level-triggered interrupt is used for wake-up from Power-down mode, the
changed level must be held for a time to wake up the MCU. This makes the MCU less
sensitive to noise. The Wake-up period is equal to the clock-counting part of the Reset
period (see Table 5). The MCU will wake up from Power-down if the input has the
required level for two Watchdog Oscillator cycles. If the wake-up period is shorter than
two Watchdog Oscillator cycles, the MCU will wake up if the input has the required level
for the duration of the Wake-up period. If the wake-up condition disappears before the
wake-up period has expired, the MCU will wake up from Power-down without executing
the corresponding interrupt.
The period of the Watchdog Oscillator is 2.7 µs (nominal) at 3.0V and 25°C. The fre-
quency of the Watchdog Oscillator is voltage dependent as shown in the Electrical
Characteristics section.
When waking up from Power-down mode, a delay from the wake-up condition occurs
until the wake-up becomes effective. This allows the clock to restart and become stable
after having been stopped. The wake-up period is defined by the same CKSEL Fuses
that define the Reset Time-out period.
1042H–AVR–04/03