I'm attempting to write a patch to take audio in from USB mic and send audio out via HDMI.

Within Audio Settings, I have two devices: bcm2835 ALSA and C-Media USB Audio Device.

Here is my basic test:
I am loading "Test Audio and MIDI" and selecting Test Tone 80dB. Below are the settings and their respective results:

Input Device 1: C-Media USB Audio Device (plug-in/hardware), Channels: 1
Output Device 1: C-Media USB Audio Device (plug-in/hardware), Channels: 2
Result: I hear a tone from USB Audio.

Input Device 1: bcm2835 (plug-in/hardware), Channels: 2
Output Device 1: bcm2835 (plug-in/hardware), Channels: 2
Result: I hear a tone over HDMI

Input Device 1: C-Media USB Audio Device (plug-in or hardware), Channels: 1
Output Device 1: bcm2835 (plug-in or hardware), Channels: 2
Result: No tone/noise at any output. PD console displayed "audio I/O stuck... closing audio"

I have tried setting USB device to slower speed (i.e. dwc_otg.speed=1) and has no effect. I am using Pd 0.43.2 (Vanilla)

Does anyone have any other ideas of why audio is stuck? Any suggestions on a solution?

Thank you very much for your help!