Datasheet

27
8246A–AVR–11/09
ATtiny2313A/4313
Reset Time-out. For more information on the pre-programmed calibration value, see the section
“Calibration Byte” on page 181.
Note: 1. The device is shipped with this option selected.
When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table 6-4.
Notes: 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.
2. The device is shipped with this option selected.
6.2.4 128 kHz Internal Oscillator
The 128 kHz Internal Oscillator is a low power Oscillator providing a clock of 128 kHz. The fre-
quency is nominal at 3 V and 25°C. This clock may be selected as the system clock by
programming the CKSEL Fuses to 0110.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table 6-5.
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.
Table 6-3. Internal Calibrated RC Oscillator Operating Modes
CKSEL3..0 Nominal Frequency
0010 4.0 MHz
0100 8.0 MHz
(1)
Table 6-4. Start-up Times for the Internal Calibrated RC Oscillator Clock Selection
SUT1..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
(2)
6 CK 14CK + 64 ms Slowly rising power
11 Reserved
Table 6-5. Start-up Times for the 128 kHz Internal Oscillator
SUT1..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