ATtiny48 Atmel Corporation, ATtiny48 Datasheet - Page 30

• Manufacturer Part Number: ATtiny48
• Manufacturer: Atmel Corporation

Specifications of ATtiny48

• Flash (kbytes): 4 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 12 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 28
• Ext Interrupts: 28
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.25
• Eeprom (bytes): 64
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

6.2.2
30
ATtiny48/88
Calibrated Internal 8MHz Oscillator
Figure 6-2.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 6-2.
When applying an external clock, it is required to avoid sudden changes in the applied clock fre-
quency to ensure stable operation of the MCU. A variation in frequency of more than 2% from
one clock cycle to the next can lead to unpredictable behavior. If changes of more than 2% is
required, ensure that the MCU is kept in Reset during the changes.
Note that the System Clock Prescaler can be used to implement run-time changes of the internal
clock frequency while still ensuring stable operation. Refer to
31
By default, the Internal Oscillator provides an approximate 8.0 MHz clock. Though voltage and
temperature dependent, this clock can be very accurately calibrated by the user. See
on page 208
“System Clock Prescaler” on page 31
When selected, this oscillator operates with no external components. During reset, hardware
loads the pre-programmed calibration value into the OSCCAL Register and thereby automati-
cally calibrates the oscillator. The accuracy of this calibration is shown as Factory calibration in
Table 22-1 on page
By changing the OSCCAL register from SW, see
page
The accuracy of this calibration is shown as User calibration in
SUT[1:0]
for details.
34, it is possible to get a higher calibration accuracy than by using the factory calibration.
00
01
10
11
6-2.
for more details. The device is shipped with the CKDIV8 Fuse programmed. See
External Clock Drive Configuration
Start-up Times for the External Clock Selection
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
208.
EXTERNAL
SIGNAL
CLOCK
for more details.
from Power-down
Start-up Time
“OSCCAL – Oscillator Calibration Register” on
Reserved
6 CK
6 CK
6 CK
CLKI
GND
“System Clock Prescaler” on page
Table 22-1 on page
from Reset (V
Additional Delay
14CK + 64 ms
14CK + 4 ms
14CK
8008H–AVR–04/11
208.
CC
Table 22-1
= 5.0V)