ATtiny43U Atmel Corporation, ATtiny43U Datasheet - Page 25

• Manufacturer Part Number: ATtiny43U
• Manufacturer: Atmel Corporation

Specifications of ATtiny43U

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 8 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• 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): 0.25
• 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: 0.7 to 5.5
• Operating Voltage (vcc): 0.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

6.2.2
8048B–AVR–03/09
Calibrated Internal 8 MHz Oscillator
When this clock source is selected, start-up times are determined by SUT Fuses as shown in
Table
Table 6-3.
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
Modes” on page 31
By default, the Internal RC Oscillator provides an approximate 8.0 MHz clock. Though voltage
and temperature dependent, this clock can be very accurately calibrated by the user. See
20-2 on page 157
See
This clock may be selected as the system clock by programming the CKSEL Fuses as shown in
Table
the pre-programmed calibration value into the OSCCAL Register and thereby automatically cal-
ibrates the RC Oscillator. The accuracy of this calibration is shown as Factory calibration in
Table 20-2 on page
By changing the OSCCAL register from SW, see
page
The accuracy of this calibration is shown as User calibration in
When this Oscillator is used as the chip clock, the Watchdog Oscillator will still be used for the
Watchdog Timer and for the Reset Time-out. For more information on the pre-programmed cali-
bration value, see the section
Table 6-4.
Notes:
SUT1..0
00
01
10
11
“System Clock Prescaler” on page 27
28, it is possible to get a higher calibration accuracy than by using the factory calibration.
6-3.
6-4. If selected, it will operate with no external components. During reset, hardware loads
1. The device is shipped with this option selected.
Start-up Times for the External Clock Selection
Internal Calibrated RC Oscillator Operating Modes
from Power-down
for more details. The device is shipped with the CKDIV8 Fuse programmed.
CKSEL3..0
for details.
157.
Start-up Time
0010
6 CK
6 CK
6 CK
(1)
“Calibration Byte” on page
for more details.
Additional Delay
Reserved
“OSCCAL – Oscillator Calibration Register” on
14CK + 64 ms
14CK + 4 ms
from Reset
14CK
142.
Nominal Frequency (MHz)
Table 20-2 on page
“Power Management and Sleep
8.0
BOD enabled
Fast rising power
Slowly rising power
Recommended Usage
157.
Table
25