Hello! I'm working with an Audio shield (Rev. D) and a Teensy 4.1. When I connect the shielding of my oscilloscope to the ground pin of the line input of the Audio shield it happens relatively often(10%) that the SGTL5000 delivers not a signal anymore. There is still a data stream but the content is digital 0! Normally there is some "live" in the lower bits even with no input signal(what is normal for an ADC). When this happens (audio input = 0) it does not help to reboot the board and restart the software. The signal stays 0. Only disconnecting the Teensy from USB brings the SGTL into normal operation again. In rare cases the SGTL5000 shows no reaction at all. That means that a reboot has a fail when calling "sgtl5000_1.enable()". Again only dis- and reconnecting to USB helps here.
I got the same effect when I connect a waveform generator to the line input. Not always but often. And it is always the ground pin. I tried different Teensy boards and different Audio shields (>10): Always the same.
Has anybody made the same experience? And has an idea how to fix that? I tried to connect a capacitor into the ground pin but it looks like it is not a frequency problem. I would assume that the ground level of the line input drops (or rises) for a short period of time when connecting a different ground from the outside which "kills" the SGTL5000. But that is only an assumption...
I got the same effect when I connect a waveform generator to the line input. Not always but often. And it is always the ground pin. I tried different Teensy boards and different Audio shields (>10): Always the same.
Has anybody made the same experience? And has an idea how to fix that? I tried to connect a capacitor into the ground pin but it looks like it is not a frequency problem. I would assume that the ground level of the line input drops (or rises) for a short period of time when connecting a different ground from the outside which "kills" the SGTL5000. But that is only an assumption...