user8275: I am trying to make a mini project with attiny84 and I searched the web so I can make an arduino on breadboard. What I saw on the internet is that they didnt use crystal. Is it mandatory if I want to use 1 pwm pin and the SPI interface on the attiny84?

user368: Only if you need crystal accuracy. If the internal RC oscillator is accurate enough then feel free to use it instead.

8275: <p>I am trying to make a mini project with attiny84 and I searched the web so I can make an arduino on breadboard. What I saw on the internet is that they didnt use crystal. Is it mandatory if I want to use 1 pwm pin and the SPI interface on the attiny84?</p>
 368: <p>Only if you need crystal accuracy. If the internal RC oscillator is accurate enough then feel free to use it instead.</p>
