ATTINY26L8SU SL383 Atmel, ATTINY26L8SU SL383 Datasheet - Page 28

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

Low-frequency Crystal
Oscillator
28
ATtiny26(L)
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown
in Table 7.
Table 7. Start-up Times for the Crystal Oscillator Clock Selection
Notes:
To use a 32.768 kHz watch crystal as the clock source for the device, the Low-fre-
quency Crystal Oscillator must be selected by setting the PLLCK to “1” and CKSEL
Fuses to “1001”. The crystal should be connected as shown in Figure 22. By program-
ming the CKOPT Fuse, the user can enable internal capacitors on XTAL1 and XTAL2,
thereby removing the need for external capacitors. The internal capacitors have a nomi-
nal value of 36 pF.
When this oscillator is selected, start-up times are determined by the SUT Fuses as
shown in Table 8.
Table 8. Start-up Times for the Low-frequency Crystal Oscillator Clock Selection
Note:
CKSEL0
SUT1..0
00
01
10
11
0
0
0
0
1
1
1
1
1. These options should only be used when not operating close to the maximum fre-
2. These options are intended for use with ceramic resonators and will ensure fre-
1. These options should only be used if frequency stability at start-up is not important
quency of the device, and only if frequency stability at start-up is not important for the
application.
quency stability at start-up. They can also be used with crystals when not operating
close to the maximum frequency of the device, and if frequency stability at start-up is
not important for the application.
for the application.
from Power-down
SUT1..0
Start-up Time
00
01
10
11
00
01
10
11
1K CK
1K CK
32K CK
(1)
(1)
from Power-down
Start-up Time
258 CK
258 CK
1K CK
1K CK
1K CK
16K CK
16K CK
16K CK
Additional Delay from
(2)
(2)
(2)
(1)
(1)
Reset (V
4.1 ms
65 ms
65 ms
CC
Additional Delay from
Reset (V
= 5.0V)
Reserved
4.1 ms
4.1 ms
4.1 ms
65 ms
65 ms
65 ms
CC
–
–
= 5.0V)
Recommended Usage
Fast rising power or BOD enabled
Slowly rising power
Stable frequency at start-up
Recommended
Usage
Ceramic resonator,
fast rising power
Ceramic resonator,
slowly rising power
Ceramic resonator,
BOD enabled
Ceramic resonator,
fast rising power
Ceramic resonator,
slowly rising power
Crystal Oscillator,
BOD enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator,
slowly rising power
1477J–AVR–06/07