Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 07:56 17 Sep 2025 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Microcontroller and PC projects : I2S DAC

Author Message
PhenixRising
Guru

Joined: 07/11/2023
Location: United Kingdom
Posts: 1531
Posted: 10:41am 15 Sep 2025
Copy link to clipboard 
Print this post

Purely for my own edification; is it possible to use the I2S DAC as a regular analogue output or would that require commands that are not supported?
 
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 5256
Posted: 10:52am 15 Sep 2025
Copy link to clipboard 
Print this post

Hi Phenix,

Please understand that audio DAC's don't necessarily have good DC performance.

The last audio DAC that could be used for DC was the TDA1540/TDA1541 from Philips (from the first generation CD players).

So if you plan to use I2S DAC's for a servo loop...forget it.

Volhout
PicomiteVGA PETSCII ROBOTS
 
PhenixRising
Guru

Joined: 07/11/2023
Location: United Kingdom
Posts: 1531
Posted: 11:20am 15 Sep 2025
Copy link to clipboard 
Print this post

  Volhout said  So if you plan to use I2S DAC's for a servo loop...forget it. Volhout




The analogue input of industrial servo-drives, only resolves to 12-bit so there would be no benefit.

I don't see DC performance being an issue, though. Observing the analog motor command from a 1KHz PID looks like horrendous noise  
 
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 5256
Posted: 11:38am 15 Sep 2025
Copy link to clipboard 
Print this post

Phenix,

DC drift is not always specifically specified, but look at below datasheet.

Typical 16 bit I2S DAC UDA1334



DC accuracy is +/-10% (0.5V+/-50mV), relates to 3.5bits DC DAC. If that is sufficient, then you can use it as a DAC in your loop.
That is why it is normal to AC-couple AUDIO DAC outputs. DC drifts all over the place.

Volhout
PicomiteVGA PETSCII ROBOTS
 
PhenixRising
Guru

Joined: 07/11/2023
Location: United Kingdom
Posts: 1531
Posted: 12:38pm 15 Sep 2025
Copy link to clipboard 
Print this post

Thanks Harm. I have no intention of doing this. I was searching through the PicoMite manual for PIO stuff and, as always, I was sidetracked  
 
Print this page


To reply to this topic, you need to log in.

The Back Shed's forum code is written, and hosted, in Australia.
© JAQ Software 2025