AT89LP428-20PU Atmel, AT89LP428-20PU Datasheet - Page 28

• Manufacturer Part Number: AT89LP428-20PU
• Description: MCU 8051 4K FLASH SPI 28PDIP
• Manufacturer: Atmel
• Series: 89LPr

Specifications of AT89LP428-20PU

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 30
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.4 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Processor Series: AT89x
• Core: 8051
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: AT89ISP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -
• Lead Free Status / Rohs Status: Details

8.2.2
28
AT89LP428/828
Reset Recovery from Power-down
Figure 8-2.
The wake-up from Power-down through an external reset is similar to the interrupt with
PWDEX = “0”. At the falling edge of RST, Power-down is exited, the oscillator is restarted, and
an internal timer begins counting as shown in
propagate to the CPU until after the timer has timed out. The time-out period is controlled by the
Start-up Timer Fuses. (See
clock cycle internal reset is generated when the internal clock restarts. Otherwise, the device will
remain in reset until RST is brought high.
Figure 8-3.
.
Internal
Internal
XTAL1
Reset
Interrupt Recovery from Power-down (PWDEX = 1)
Internal
Reset Recovery from Power-down
Clock
PWD
XTAL1
RST
Clock
PWD
INT1
Table 7-1 on page
Figure
25). If RST returns high before the time-out, a two
8-3. The internal clock will not be allowed to
t SUT
3654A–MICRO–8/09