How to make ATtiny13 running at 128 kHz clock source

The ATtiny13’s default clock source setting is the Internal RC Oscillator running at 9.6MHz with clock divider /8 (fuses L=0x6A and H=0xFF; see fuse calculator). This short article explains how to downclock the ATtiny13 by swtiching to Internal RC Oscillator running at 128kHz without clock divider (fuses L=0x7B and H=0xFF) and still have a control to program AVR … Read more