I have my Attiny13a turning on a single led. It works fine when I power it from Arduino 5V, but it doesn't work with my LM317 5V.
My LM317 has R1=240 Ohms and R2 =720 Ohms. It is connected to a 12V 120W power source. It gives measured 5V.
I've tried to add caps of different capacitance. It hasn't helped. I've tried to add some resistors (51 - 300 Ohms) in parallel with the Attiny and it hasn't helped.
I've measure it with my oscilloscope - the voltage is stable.
I've changed R2 to 620 Ohms to lower the voltage cause Arduino supplies about 4.5V. It hasn't helped.
What am I doing wrong?