ATMEGA16-16AU SL602 Atmel, ATMEGA16-16AU SL602 Datasheet - Page 29

• Manufacturer Part Number: ATMEGA16-16AU SL602
• Manufacturer: Atmel

Calibrated Internal
RC Oscillator
2466T–AVR–07/10
When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 8. Start-up Times for the External RC Oscillator Clock Selection
Note:
The Calibrated Internal RC Oscillator provides a fixed 1.0 MHz, 2.0 MHz, 4.0 MHz, or 8.0 MHz
clock. All frequencies are nominal values at 5V and 25°C. This clock may be selected as the
system-clock by programming the CKSEL Fuses as shown in
with no external components. The CKOPT Fuse should always be unpro-grammed when using
this clock option. During Reset, hardware loads the calibration byte into the OSCCAL Register
and thereby automatically calibrates the RC Oscillator. At 5V, 25°C and 1.0 MHz, 2.0 MHz, 4.0
MHz or 8.0 MHz Oscillator frequency selected, this calibration gives a frequency within ±3% of
the nominal frequency. Using calibration methods as described in application notes available at
www.atmel.com/avr it is possible to achieve ±1% accuracy at any given V
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 9. Internal Calibrated RC Oscillator Operating Modes
Note:
When this Oscillator is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 10. Start-up Times for the Internal Calibrated RC Oscillator Clock Selection
Note:
SUT1..0
SUT1..0
10
00
01
10
11
00
01
11
(1)
8.
10. XTAL1 and XTAL2 should be left unconnected (NC).
1. This option should not be used when operating close to the maximum frequency of the device.
1. The device is shipped with this option selected.
1. The device is shipped with this option selected.
CKSEL3..0
Start-up Time from
Power-down and
0001
0010
0011
0100
Start-up Time from
Power-save
Power-down and
(1)
6 CK
18 CK
18 CK
18 CK
Power-save
6 CK
6 CK
6 CK
(1)
“Calibration Byte” on page
Additional Delay
(V
from Reset
CC
4.1 ms
4.1 ms
65 ms
Additional Delay
= 5.0V)
–
(V
from Reset
CC
4.1 ms
65 ms
Reserved
= 5.0V)
–
Nominal Frequency (MHz)
Recommended Usage
BOD enabled
Fast rising power
Slowly rising power
Fast rising power or BOD enabled
261.
1.0
2.0
4.0
8.0
Recommended Usage
BOD enabled
Fast rising power
Slowly rising power
Table
9. If selected, it will operate
ATmega16(L)
CC
and Temperature.
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