Atmel ATtiny13A, Руководство пользователя

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8126F–AVR–05/12
ATtiny13A
When this Oscillator is selected, start-up times are determined by the SUT fuses as shown in
Table 6-5 .
Notes: 1. The device is shipped with this option selected.
2. If the RSTDISBL fuse is programmed, this start-up time will be increased to 14CK + 4 ms to
ensure programming mode can be entered.
6.2.3 Internal 128 kHz Oscillator
The 128 kHz internal Oscillator is a low power Oscillator providing a clock of 128 kHz. The fre-
quency depends on supply voltage, temperature and batch variations. This clock may be select
as the system clock by programming the CKSEL fuses to “11”.
When this clock source is selected, start-up times are determined by the SUT fuses as shown in
Table 6-6 .
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 = “10”, SUT = “10”, and CKDIV8 programmed. The default
clock source setting is therefore the Internal RC Oscillator running at 9.6 MHz with longest start-
up time and an initial system clock prescaling of 8. This default setting ensures that all users can
make their desired clock source setting using an In-System or High-voltage Programmer.
6.3 System Clock Prescaler
The ATtiny13A system clock can be divided by setting the “CLKPR – Clock Prescale Register”
on page 28 . This feature can be used to decrease power consumption when the requirement for
processing power is low. This can be used with all clock source options, and it will affect the
clock frequency of the CPU and all synchronous peripherals. clk
I/O
, clk
ADC
, clk
CPU
, and clk
FLASH
are divided by a factor as shown in Table 6-8 on page 28 .
Table 6-5. Start-up Times for the Internal Calibrated RC Oscillator Clock Selection
SUT[1:0]
Start-up Time
from Power-down
Additional Delay from
Reset (V
CC
= 5.0V) Recommended Usage
00 6 CK 14CK
(2)
BOD enabled
01 6 CK 14CK + 4 ms Fast rising power
10
(1)
6 CK 14CK + 64 ms Slowly rising power
11 Reserved
Table 6-6. Start-up Times for the 128 kHz Internal Oscillator
SUT[1:0]
Start-up Time from
Power-down and Power-save
Additional Delay
from Reset
Recommended
Usage
00 6 CK 14CK
(1)
BOD enabled
01 6 CK 14CK + 4 ms Fast rising power
10 6 CK 14CK + 64 ms Slowly rising power
11 Reserved