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Joined: Thu Jul 19, 2018 1:15 pm

LoFi 8bit audio DAC

Thu Jul 19, 2018 1:26 pm

I would like some kind of 8bit audio output from a raspberry. I know it is possible to route audio through ALSA to a covox speech thing or similar parallel input DAC using a printer port on a regular PC but it seems unnecessary to go via a printer port when I believe it may be possible to use GPIO pins instead. Does anyone know if there is ALSA support for an 8bit GPIO connected DAC with parallel input? I think the original covox speech thing used resistor ladder but I already have clone using AD558 dac ic instead.

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Re: LoFi 8bit audio DAC

Thu Jul 19, 2018 3:05 pm

Nobody is using an 8-bit port to generate audio, that is really a very retro way of doing it.
The PI has several audio output methods, the simplest one is that it has two PWM generators, which generate stereo through an updated (optimized) PWM algorithm, the audio quality has steadily improved in the past, and now is of "FM" quality.
The next better audio output is HDMI audio, but the best quality is generated using the PI's I2S (inter IC sound) bus, that drives an audio codex, its also the only two-way audio system, so it can be used for audio input.
Then there is also the option to use an USB sound device.

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