ATTINY11(2003) View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

ATTINY11
(Rev.:2003)

8-bit Microcontroller with 1K Byte Flash

Atmel Corporation 

Power-on Reset for the

ATtiny11

A Power-on Reset (POR) circuit ensures that the device is reset from power-on. As

shown in Figure 16, an internal timer is clocked from the watchdog timer. This timer pre-

vents the MCU from starting a certain period after VCC has reached the Power-on

Threshold Voltage – VPOT. See Figure 18. The total reset period is the Delay Time-out

period – tTOUT. The FSTRT fuse bit in the Flash can be programmed to give a shorter

start-up time.The start-up times for the different clock options are shown in the following

table. The Watchdog Oscillator is used for timing the start-up time, and this oscillator is

voltage dependent as shown in the section “ATtiny11 Typical Characteristics” on page

60.

Table 7. Start-up Times for the ATtiny11 (VCC = 2.7V)

Start-up Time tTOUT

Selected Clock Option

FSTRT Unprogrammed

FSTRT Programmed

External Crystal

67 ms

4.2 ms

External Ceramic Resonator

67 ms

4.2 ms

External Low-frequency Crystal

4.2 s

4.2 s

External RC Oscillator

4.2 ms

67 µs

Internal RC Oscillator

4.2 ms

67 µs

External Clock

4.2 ms

5 clocks from reset,

2 clocks from power-down

If the built-in start-up delay is sufficient, RESET can be connected to VCC directly or via

an external pull-up resistor. By holding the RESET pin low for a period after VCC has

been applied, the Power-on Reset period can be extended. Refer to Figure 19 for a tim-

ing example on this.

18 ATtiny11/12

1006D–AVR–07/03

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