ATTINY44A-CCUR Atmel, ATTINY44A-CCUR Datasheet - Page 28

• Manufacturer Part Number: ATTINY44A-CCUR
• Description: MCU AVR 4KB FLASH 20MHZ 15UFBGA
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY44A-CCUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 12
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.2.4
6.2.5
28
ATtiny24A/44A/84A
Low-Frequency Crystal Oscillator
Crystal Oscillator / Ceramic Resonator
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 ‘0110’. The crystal should be connected
as shown in
For this oscillator start-up times can be set with the SUT fuses, as shown in
Table 6-7.
Notes:
The Low-frequency Crystal Oscillator provides an internal load capacitance, see
each TOSC pin.
Table 6-8.
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.
Figure 6-3.
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
SUT[1:0]
ATtiny24A/44A/84A
00
01
10
11
1. These options should be used only if frequency stability at start-up is not important.
Device
Figure
Start-up Times for the Low Frequency Crystal Oscillator Clock Selection
Capacitance of Low-Frequency Crystal Oscillator
from Power Down
Crystal Oscillator Connections
Start-up Time
6-3. To find suitable capacitors please consult the manufacturer’s datasheet.
1K CK
1K CK
32K CK
(1)
(1)
32 kHz Osc. Type
System Osc.
C2
C1
Additional Delay
from Reset
64 ms
64 ms
4 ms
Reserved
Cap (Xtal1/Tosc1)
XTAL2
XTAL1
GND
Figure 6-3
16 pF
Slowly rising power
Recommended usage
Fast rising power or BOD enabled
Stable frequency at start-up
Either a quartz crystal or a
Table
Cap (Xtal2/Tosc2)
8183C–AVR–03/11
6-7.
6 pF
Table 6-8
at