Simple audio cape for the Beaglebone Black.
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First of all: This project is a clone of CircuitCo Audio Cape.

It is not commercial in any form, just fun for me to play around. If you want an Audio Cape, go and get one of theirs.



Project schematic.


Render of the board.

Setup on Arch

The setup guide is mainly taken from - BBB Audio Cape RevB Getting Started.

Get the tools if not already installed:

pacman -S wget

pacman -S unzip

pacman -S dct-overlay

Download and unzip the device tree source:



Compile the device tree file and move it to /lib/firmware:

dtc -O dtb -o BB-BONE-AUDI-02-00A0.dtbo -b 0 -@ BB-BONE-AUDI-02-00A0.dts

mv BB-BONE-AUDI-02-00A0.dtbo /lib/firmware

Notice that the dtc-overlay version needs to be installed, since the old dtc is not accepting the @ option.

The Cape is sharing the audio signal with the onboard HDMI. Therefore HDMI audio needs to be disabled. Edit the uEnv.txt file, that your uboot is using:


In order to activate the cape you need to reboot. Load the Device Tree file for the cape:

echo BB-BONE-AUDI-02 > /sys/devices/bone_capemgr*/slots

To make that persistent just add the following line in /etc/default/capemgr :


Test and play

Play alternating noise on the 2 output channels:

speaker-test -c 2

Play alternating sine waves on the 2 output channels:

speaker-test -c 2 -t sine


Identifier Type/Value Quantity Comment Supplier Id Supplier
R1, R2 0 Ω 2 not populated SMD-0603 0 Reichelt
R5, R6 33 Ω 2 SMD-0603 33 Reichelt
C3, C4, C20, C21 47 pF 2 NPO-G0603 47P Reichelt
C13 10 nF 1 X7R-G0603 10N Reichelt
C1, C2, C5, C6, C15, C16 100 nF 6 X7R-G0603 100N Reichelt
C7-C10, C14, C17 10 µF 6 X5R-G0603 10/6 Reichelt
C18, C19 47 µF 2 X5R-G1206 47/6 Reichelt
J1, J2 4pol TRS Jack 2 LUM 1503-13V Reichelt
J3, J4 2row Pin Header 2 SL 2X25G 2,54 Reichelt
D1-D4 Suppressor Diodes 4 863-ESD9B3.3ST5G Mouser
U1 Stereo CODEC 1 595-TLV320C3104IRHBT Mouser
U2 LDO 1.8V 1 595-TLV70218DBVR Mouser