ATtiny25 Automotive Atmel Corporation, ATtiny25 Automotive Datasheet - Page 24

• Manufacturer Part Number: ATtiny25 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATtiny25 Automotive

• Flash (kbytes): 2 Kbytes
• Pin Count: 8
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 4
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 6
• Ext Interrupts: 6
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 125
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 5
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

6.3
6.4
24
Default Clock Source
Crystal Oscillator
ATtiny25/45/85
Table 6-2.
The device is shipped with CKSEL = “0010”, SUT = “10”, and CKDIV8 programmed. The default
clock source setting is therefore the Internal RC Oscillator running at 8 MHz with longest start-up
time and an initial system clock prescaling of 8. This default setting ensures that all users can
make their desired clock source setting using an In-System or High-voltage Programmer.
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.
Figure 6-3.
The Oscillator can operate in three different modes, each optimized for a specific frequency
range. The operating mode is selected by the fuses CKSEL3..1 as shown in
Table 6-3.
Notes:
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown in
6-4.
CKSEL3..1
100
101
110
111
(1)
1. This option should not be used with crystals, only with ceramic resonators.
Typ Time-out
Number of Watchdog Oscillator Cycles
Crystal Oscillator Connections
Crystal Oscillator Operating Modes
64 ms
4 ms
Frequency Range (MHz)
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
8.0 -
Table
6-3. For ceramic resonators, the capacitor values given by
C2
C1
Recommended Range for Capacitors C1 and
XTAL2
XTAL1
GND
Figure
C2 for Use with Crystals (pF)
Number of Cycles
6-3. Either a quartz crystal or a
8K (8,192)
512
12 - 22
12 - 22
12 - 22
–
Table
7598H–AVR–07/09
6-3.
Table