The 128kHz internal Oscillator is a low power Oscillator providing a clock of 128kHz. This clock may be select as the system clock by programming the CKSEL Fuses to '0011':
Nominal Frequency(1) | CKSEL[3:0] |
---|---|
128kHz | 0011 |
When this clock source is selected, start-up times are determined by the SUT Fuses:
Power Conditions | Start-Up Time from Power-down and Power-save | Additional Delay from Reset | SUT[1:0] |
---|---|---|---|
BOD enabled | 6 CK | 14CK | 00 |
Fast rising power | 6 CK | 14CK + 4ms | 01 |
Slowly rising power | 6 CK | 14CK + 65ms | 10 |
Reserved | 11 |