Disclaimer

This information is provided for experimenters. No support will be provided by NW Digital Radio. Some underlying software is not well tested and may break in unexpected ways.  Not all applications will have access to the virtual sound cards created.

Use at your own risk, backup prior configurations and be prepared to delete any modifications and to restore prior configurations.

Modify Your Configuration

No longer required on current install images.

Edit /boot/config.txt and include the line

dtoverlay=i2s-mmap

Save and reboot

Create or Edit /etc/asound.conf

Obtain the file from github

# for UDRC
cd ~
curl -L -s https://raw.githubusercontent.com/nwdigitalradio/udrc-tools/master/udrc-setup/asound.conf > asound.conf

# or for the DRAWS
cd ~
curl -L -s https://raw.githubusercontent.com/nwdigitalradio/udrc-tools/master/udrc-setup/asound-draws.conf > asound.conf

You can put it in ~/.asoundrc for a single user

mv asound.conf .asoundrc

Or make it apply for the whole system by editing /etc/asound.conf or replacing /etc/asound.conf

sudo cp asound.conf /etc/asound.conf

Verify The New Devices

aplay -L

null
    Discard all samples (playback) or generate zero samples (capture)
udrc_out
udrc_in
din6_out
hd15_out
din6_in
hd15_in
din6
hd15
subdin6
subhd15
sysdefault:CARD=udrc
    udrc,
    Default Audio Device
dmix:CARD=udrc,DEV=0
    udrc,
    Direct sample mixing device
dsnoop:CARD=udrc,DEV=0
    udrc,
    Direct sample snooping device
hw:CARD=udrc,DEV=0
    udrc,
    Direct hardware device without any conversions
plughw:CARD=udrc,DEV=0
    udrc,
    Hardware device with all software conversions

Examples

Use in direwolf.conf

For example in direwolf.conf, use logical sound card din6, substitute left or right on draws setup.

ADEVICE1 din6
ACHANNELS 1
CHANNEL 0
MODEM 1200
MYCALL UN1X-3
PTT GPIO 23