ATTINY26L8SU SL383 Atmel, ATTINY26L8SU SL383 Datasheet - Page 29

• Manufacturer Part Number: ATTINY26L8SU SL383
• Description: MCU 8-Bit ATtiny AVR RISC 2KB Flash 3.3V/5V 20-Pin SOIC T/R
• Manufacturer: Atmel

External RC Oscillator
1477J–AVR–06/07
For timing insensitive applications, the external RC configuration shown in Figure 23
can be used. The frequency is roughly estimated by the equation f = 1/(3RC). C should
be at least 22 pF. By programming the CKOPT Fuse, the user can enable an internal
36 pF capacitor between XTAL1 and GND, thereby removing the need for an external
capacitor.
Figure 23. External RC Configuration
The oscillator can operate in four different modes, each optimized for a specific fre-
quency range. The operating mode is selected by the fuses CKSEL3..0 as shown in
Table 9.
Table 9. External RC Oscillator Operating Modes
When this oscillator is selected, start-up times are determined by the SUT Fuses as
shown in Table 10.
Table 10. Start-up Times for the External RC Oscillator Clock Selection
Notes:
SUT1..0
00
01
10
11
1. This option should not be used when operating close to the maximum frequency of
the device.
from Power-down
Start-up Time
CKSEL3..0
6 CK
18 CK
18 CK
18 CK
0101
0110
0111
1000
(1)
R
C
Additional Delay from
V
Reset (V
CC
4.1 ms
4.1 ms
65 ms
CC
–
PB5 (XTAL2)
XTAL1
GND
= 5.0V)
Frequency Range (MHz)
Recommended Usage
BOD enabled
Fast rising power
Slowly rising power
Fast rising power or BOD enabled
8.0 - 12.0
0.1 - 0.9
0.9 - 3.0
3.0 - 8.0
ATtiny26(L)
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