AT89LP428-20MU ATMEL [ATMEL Corporation], AT89LP428-20MU Datasheet - Page 28

• Manufacturer Part Number: AT89LP428-20MU
• Description: 8-bit Microcontroller with 4K/8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

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