I2S DAC

Author	Message
PhenixRising Guru Joined: 07/11/2023 Location: United Kingdom Posts: 1637	Posted: 10:41am 15 Sep 2025       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: 5464	Posted: 10:52am 15 Sep 2025       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
PhenixRising Guru Joined: 07/11/2023 Location: United Kingdom Posts: 1637	Posted: 11:20am 15 Sep 2025         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: 5464	Posted: 11:38am 15 Sep 2025       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
PhenixRising Guru Joined: 07/11/2023 Location: United Kingdom Posts: 1637	Posted: 12:38pm 15 Sep 2025       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