The factory calibration accuracy of internal 8MHz RC oscillator is improved from ±10% in ATtiny4/5/9/10 to ±3% in ATtiny102/104. It is also possible to manually calibrate the internal oscillator to be more accurate than default factory calibration.
| Calibration method | Target frequency | VCC | Temperature | Accuracy at given voltage andtemperature |
|---|---|---|---|---|
| Factory calibration | 8.0MHz | 2.7 - 4.0V | 0°C - 85°C | ±3% |
| User calibration | Fixed frequency within: 7.3 - 8.1MHz | Fixed voltage within: 1.8 - 5.5V | Fixed temp. within: -40°C - 85°C | ±1% |