ATtiny43U datasheet(26/182 Pages) ATMEL

26 / 182 page

8048B–AVR–03/09

ATtiny43U

When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in

Table 6-5 below.

Note:

1. If the RSTDISBL fuse is programmed, this start-up time will be increased to

14CK + 4 ms to ensure programming mode can be entered.

The device is shipped with this option selected.

6.2.3

Internal 128 kHz Oscillator

The 128 kHz internal oscillator is a low power oscillator providing a clock of 128 kHz. The fre-

quency is nominal at 3V and 25

°C. This clock may be select as the system clock by

programming the CKSEL Fuses to “11” as shown in Table 6-6 below.

When this clock source is selected, start-up times are determined by the SUT Fuses as shown in

Table 6-7 below.

Note:

1. If the RSTDISBL fuse is programmed, this start-up time will be increased to 14CK + 4 ms to

ensure programming mode can be entered.

6.2.4

Default Clock Source

The device is shipped with CKSEL = "0010", SUT = "10", and CKDIV8 programmed. The default

clock source is therefore the internal RC oscillator running at 8.0 MHz with the longest start-up

time and an initial system clock prescale setting of 8, resulting in a 1 MHz system clock. The

default setting ensures every user can make the desired clock source setting using any available

programming interface.

Table 6-5.

Start-up times for Internal Calibrated RC Oscillator Clock Selection

SUT1..0

Start-up Time

from Power-down

Additional Delay from

Reset (V

CC = 5.0V)

Recommended Usage

6 CK

14CK(1)

BOD enabled

6 CK

14CK + 4 ms

Fast rising power

10(2)

6 CK

14CK + 64 ms

Slowly rising power

Reserved

Table 6-6.

128 kHz Internal Oscillator Operating Modes

CKSEL3..0

Nominal Frequency

0011

128 kHz

Table 6-7.

Start-up Times for the 128 kHz Internal Oscillator

SUT1..0

Start-up Time

from Power-down

Additional Delay

from Reset

Recommended Usage

6 CK

14CK(1)

BOD enabled

6 CK

14CK + 4 ms

Fast rising power

6 CK

14CK + 64 ms

Slowly rising power

Reserved

ATtiny43U 데이터시트(PDF) 26 Page - ATMEL Corporation

ATtiny43U 데이터시트(HTML) 26 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

데이터시트 다운로드

링크 URL