ATTINY261-15MZ Atmel, ATTINY261-15MZ Datasheet - Page 30

• Manufacturer Part Number: ATTINY261-15MZ
• Description: MCU AVR 2K FLASH 15MHZ 32-QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY261-15MZ

• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Speed: 16MHz
• Number Of I /o: 16
• Eeprom Size: 128 x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Program Memory Size: 2KB (2K x 8)
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Connectivity: USI
• Core Size: 8-Bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7.7
7.8
7.9
30
128 kHz Internal Oscillator
Low-frequency Crystal Oscillator
Crystal Oscillator
ATtiny261/ATtiny461/ATtiny861
The 128 kHz internal Oscillator is a low power Oscillator providing a clock of 128 kHz. The fre-
quency is nominal at 3V and 25°C. This clock may be select as the system clock by
programming the CKSEL Fuses to “0011”.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 7-8.
To use a 32.768 kHz watch crystal as the clock source for the device, the low-frequency crystal
oscillator must be selected by setting CKSEL fuses to ‘0100’. The crystal should be connected
as shown in
oscillator operation and how to choose appropriate values for C1 and C2.
When this oscillator is selected, start-up times are determined by the SUT fuses as shown in
Table
Table 7-9.
Notes:
XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be con-
figured for use as an On-chip Oscillator, as shown in
ceramic resonator may be used.
C1 and C2 should always be equal for both crystals and resonators. The optimal value of the
capacitors depends on the crystal or resonator in use, the amount of stray capacitance, and the
electromagnetic noise of the environment. Some initial guidelines for choosing capacitors for
use with crystals are given in
the manufacturer should be used.
SUT1..0
SUT1..0
00
01
10
11
00
01
10
11
7-8.
7-9.
1. These options should only be used if frequency stability at start-up is not important for the
application.
Start-up Time from Power
Figure
Power-down and Power-save
Down and Power Save
Start-up Times for the 128 kHz Internal Oscillator
Start-up Times for the Low Frequency Crystal Oscillator Clock Selection
32K (32768) CK
1K (1024) CK
1K (1024) CK
Start-up Time from
7-4. Refer to the 32 kHz Crystal Oscillator Application Note for details on
6 CK
6 CK
6 CK
Table
(1)
(1)
7-10. For ceramic resonators, the capacitor values given by
Additional Delay from
Reset (V
Additional Delay from
64 ms
64 ms
4 ms
Reserved
Reserved
14CK + 64 ms
14CK + 4 ms
CC
= 5.0V)
Reset
14CK
Figure
7-4. Either a quartz crystal or a
Recommended usage
Fast rising power or BOD enabled
Slowly rising power
Stable frequency at start-up
BOD enabled
Fast rising power
Slowly rising power
Recommended Usage
7753F–AVR–01/11