u/mnemocronin r/embedded • Recommends
On “Generate a voltage that varies over time for dac output.”
It really sounds like you lack a very fundamental understanding of sampled signals. What you are looking for is a DDS (direct digital synthesis). Start somewhere simple, like a youtube video on how to generate a sine wave. Try to understand the principle of how a signal is sampled both in time and in its value e.g. link to this video