ATTINY48-MMHR Atmel, ATTINY48-MMHR Datasheet - Page 30

• Manufacturer Part Number: ATTINY48-MMHR
• Description: MCU AVR 4KB FLASH 12MHZ 28QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY48-MMHR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 12MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 24
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 64 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

6.2.2
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
8008G–AVR–04/11
208.
CC
Table 22-1
= 5.0V)