Thanks for that Nugget WIlliam. That worked for me just now (PI-2, UDRC Hat).

Cheers
John
EI7IG

Can you explain why I would need the `dtoverlay=` line?

The original UDRC & some of the UDRC II HATs have their DT (Device Tree)
overlay files in EEPROM on the HAT. The DT overlay in the HAT EEPROM is
automatically loaded by the boot firmware. The DT overlay file for the
UDRC II & DRAWS HATs grew too large for the EEPROM so are now only
loaded dynamically from the /boot/overlays directory.

Using dtoverlay= ends the current overlay scope so that the UDRC or
DRAWS overlay in the /boot/overlays directory can be loaded by a
subsequent dtoverlay=udrc or dtoverlay=draws command.
dtoverlay= effectively suppresses the loading of the HAT overlay in EEPROM.

Any dtparam or dtoverlay directives must come after the dtoverlay= line.

/Basil n7nix

Thanks for the explanation!

On Wed, Dec 4, 2019 at 11:24 AM Ryan Matthew Headley
<headley.ryan@gmail.com> wrote:

The purpose of 'dtoverlay=' is to clear any previous like settings in the file so that 'dtoverlay=draws' will be accepted.

On Wed, Dec 4, 2019 at 11:17 AM William McKeehan <ki4hdu@gmail.com> wrote:

That alone did not resolve the issue, but adding `dtoverlay=` directly
above the `dtoverlay=draws,alsaname=udrc` line, then moving the entire
DRAWS block to be above `dtparam=audio=on` seems to have things
working.

Can you explain why I would need the `dtoverlay=` line?

Thanks for the help!

On Wed, Dec 4, 2019 at 10:44 AM Ryan Matthew Headley
<headley.ryan@gmail.com> wrote:

Place

dtoverlay=

directly above

dtoverlay=draws,alsaname=udrc

in /boot/config.txt


On Wed, Dec 4, 2019 at 9:13 AM William McKeehan <ki4hdu@gmail.com> wrote:

Is there a guide for setting up the DRAWS hat with Buster?

I started with a clean image, and tried to enable the DRAWS by adding `dtoverlay=draws` to the /boot/config.txt file, but when the pi starts, `aplay -l` does not list the draws audio device and the GPS devices (ttySC0 and pps0) are also not available.

The hat appears to be installed:
/proc/device-tree/hat/name: hat
/proc/device-tree/hat/product: Digital Radio Amateur Work Station
/proc/device-tree/hat/product_id: 0x0004
/proc/device-tree/hat/product_ver: 0x0204
/proc/device-tree/hat/uuid: 7b87530a-0975-43cc-bbc0-203350f4c6e9
/proc/device-tree/hat/vendor: NW Digital Radio

I added the dtoverlay to the end of the /boot/config.txt file:

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
dtoverlay=vc4-fkms-v3d

# DRAWS related:
# this adds the udrc driver to the device tree
dtoverlay=draws,alsaname=udrc
# https://www.raspberrypi.org/documentation/configuration/config-txt/overclocking.md
force_turbo=1

but don't see the audio device:
**** List of PLAYBACK Hardware Devices ****
card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
Subdevices: 7/7
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 IEC958/HDMI [bcm2835 IEC958/HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: ALSA [bcm2835 ALSA], device 2: bcm2835 IEC958/HDMI1 [bcm2835 IEC958/HDMI1]
Subdevices: 1/1
Subdevice #0: subdevice #0

If someone could point me to some debugging steps, I'd appreciate it.

Thanks!
William
KI4HDU

--
***************************
Ryan Matthew Headley
1705 Granby Road
Cayce, SC 29033 USA

mobile - +1803-386-1799

--
William
KI4HDU

--
***************************
Ryan Matthew Headley
1705 Granby Road
Cayce, SC 29033 USA

mobile - +1803-386-1799

--
William
KI4HDU

--

That alone did not resolve the issue, but adding `dtoverlay=` directly
above the `dtoverlay=draws,alsaname=udrc` line, then moving the entire
DRAWS block to be above `dtparam=audio=on` seems to have things
working.

Can you explain why I would need the `dtoverlay=` line?

Thanks for the help!

On Wed, Dec 4, 2019 at 10:44 AM Ryan Matthew Headley
<headley.ryan@gmail.com> wrote:

Place

dtoverlay=

directly above

dtoverlay=draws,alsaname=udrc

in /boot/config.txt


On Wed, Dec 4, 2019 at 9:13 AM William McKeehan <ki4hdu@gmail.com> wrote:

Is there a guide for setting up the DRAWS hat with Buster?

I started with a clean image, and tried to enable the DRAWS by adding `dtoverlay=draws` to the /boot/config.txt file, but when the pi starts, `aplay -l` does not list the draws audio device and the GPS devices (ttySC0 and pps0) are also not available.

The hat appears to be installed:
/proc/device-tree/hat/name: hat
/proc/device-tree/hat/product: Digital Radio Amateur Work Station
/proc/device-tree/hat/product_id: 0x0004
/proc/device-tree/hat/product_ver: 0x0204
/proc/device-tree/hat/uuid: 7b87530a-0975-43cc-bbc0-203350f4c6e9
/proc/device-tree/hat/vendor: NW Digital Radio

I added the dtoverlay to the end of the /boot/config.txt file:

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
dtoverlay=vc4-fkms-v3d

# DRAWS related:
# this adds the udrc driver to the device tree
dtoverlay=draws,alsaname=udrc
# https://www.raspberrypi.org/documentation/configuration/config-txt/overclocking.md
force_turbo=1

but don't see the audio device:
**** List of PLAYBACK Hardware Devices ****
card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
Subdevices: 7/7
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 IEC958/HDMI [bcm2835 IEC958/HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: ALSA [bcm2835 ALSA], device 2: bcm2835 IEC958/HDMI1 [bcm2835 IEC958/HDMI1]
Subdevices: 1/1
Subdevice #0: subdevice #0

If someone could point me to some debugging steps, I'd appreciate it.

Thanks!
William
KI4HDU

--
***************************
Ryan Matthew Headley
1705 Granby Road
Cayce, SC 29033 USA

mobile - +1803-386-1799

--
William
KI4HDU

--

Is there a guide for setting up the DRAWS hat with Buster?

I started with a clean image, and tried to enable the DRAWS by adding `dtoverlay=draws` to the /boot/config.txt file, but when the pi starts, `aplay -l` does not list the draws audio device and the GPS devices (ttySC0 and pps0) are also not available.

The hat appears to be installed: