Datasheet

 2018 Microchip Technology Inc. Data Sheet Complete DS40002060A-page 126
ATtiny4/5/9/10
17.4 Clock Characteristics
17.4.1 Accuracy of Calibrated Internal Oscillator
It is possible to manually calibrate the internal oscillator to be more accurate than default factory calibration. Note that the
oscillator frequency depends on temperature and voltage. Voltage and temperature characteristics can be found in Figure
18-39 on page 150 and Figure 18-40 on page 150.
Notes: 1. Accuracy of oscillator frequency at calibration point (fixed temperature and fixed voltage).
17.4.2 External Clock Drive
Figure 17-2. External Clock Drive Waveform
Table 17-2. Calibration Accuracy of Internal RC Oscillator
Calibration
Method Target Frequency V
CC
Temperature
Accuracy at given Voltage
& Temperature
(1)
Factory
Calibration
8.0 MHz 3V 25C 10%
User
Calibration
Fixed frequency within:
7.3 – 8.1 MHz
Fixed voltage within:
1.8V – 5.5V
Fixed temp. within:
-40C – 85C
1%
Table 17-3. External Clock Drive Characteristics
Symbol Parameter
V
CC
= 1.8 - 5.5V V
CC
= 2.7 - 5.5V V
CC
= 4.5 - 5.5V
UnitsMin. Max. Min. Max. Min. Max.
1/t
CLCL
Clock Frequency 0 4 0 8 0 12 MHz
t
CLCL
Clock Period 250 125 83 ns
t
CHCX
High Time 100 50 33 ns
t
CLCX
Low Time 100 50 33 ns
t
CLCH
Rise Time 2.0 1 0.6 s
t
CHCL
Fall Time 2.0 1 0.6 s
t
CLCL
Change in period from one clock cycle to the next 2 2 2 %
V
IL1
V
IH1