attiny24v ATMEL Corporation, attiny24v Datasheet - Page 27

• Manufacturer Part Number: attiny24v
• Description: 8-bit Avr Microcontroller With 2/4/8k Bytes Insystem Programmable Flash
• Manufacturer: ATMEL Corporation

6.2.3
8006H–AVR–10/09
Internal 128 kHz Oscillator
ibrates the RC Oscillator. The accuracy of this calibration is shown as Factory calibration in
Table 20-2 on page
By changing the OSCCAL register from SW, see
page
The accuracy of this calibration is shown as User calibration in
When this Oscillator is used as the chip clock, the Watchdog Oscillator will still be used for the
Watchdog Timer and for the Reset Time-out. For more information on the pre-programmed cali-
bration value, see the section
Table 6-4.
Note:
When this oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 6-5.
Note:
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
selected as the system clock by programming the CKSEL Fuses to “0100”.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 6-6.
Note:
SUT1..0
SUT1..0
10
00
01
11
00
01
10
11
30, it is possible to get a higher calibration accuracy than by using the factory calibration.
(1)
6-5..
6-6.
1. The device is shipped with this option selected.
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
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.
ensure programming mode can be entered.
Internal Calibrated RC Oscillator Operating Modes
Start-up Times for the Internal Calibrated RC Oscillator Clock Selection
Start-up Times for the 128 kHz Internal Oscillator
from Power-down
from Power-down
CKSEL3..0
176.
0010
Start-up Time
Start-up Time
6 CK
6 CK
6 CK
6 CK
6 CK
6 CK
(1)
“Calibration Byte” on page
Additional Delay from
Reset (V
Additional Delay
Reserved
“OSCCAL – Oscillator Calibration Register” on
Reserved
14CK + 64 ms
14CK + 64 ms
14CK + 4 ms
14CK + 4 ms
from Reset
14CK
14CK
CC
162.
(2)
(1)
= 5.0V)
Nominal Frequency
Table 20-2 on page
ATtiny24/44/84
8.0 MHz
Recommended Usage
BOD enabled
Fast rising power
Slowly rising power
BOD enabled
Fast rising power
Slowly rising power
Recommended
Usage
176.
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