Adafruit Uda1334a User manual

Adafruit I2S Stereo Decoder - UDA1334A

Created by lady ada

Last updated on 2019-01-30 06:56:56 PM UTC

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Guide Contents

Overview

Pinouts

Power Pins

I2S Pins

Audio Outputs

Optional Control Pins

Assembly

Installing Standard Headers

Raspberry Pi Wiring

Raspberry Pi Setup

Fast Install

Detailed Install

Update /etc/modprobe.d (if it exists)

Disable headphone audio (if it's set)

Create asound.conf file

Add Device Tree Overlay

Raspberry Pi Test

Speaker Tests!

Simple white noise speaker test

Simple WAV speaker test

Simple MP3 speaker test

Volume adjustment

Pi I2S Tweaks

Reducing popping

Step 1

Add software volume control

Play Audio with PyGame

Install PyGame

Run Demo

Arduino Wiring & Test

Wiring

Basic Test

DMA Test

CircuitPython Wiring & Test

Wiring

Code Examples

Tone Generation

Wave File

Where's my I2S?

Downloads

Files

Schematic & Fabrication Print

Overview

This fully-featured UDA1334A I2S Stereo DAC breakout is a perfect match for any I2S-output audio interface. It's

affordable but sounds great! The NXP UDA1334A is a jack-of-all-I2S-trades: you can use 3.3V - 5V logic levels (a rarity),

and can process multiple different formats by setting two pins to high or low. The DAC will process data immediately,

and give you a clear, analog, stereo line level output. It's even cool with MCLK-less I2S interfaces such as the

Raspberry Pi (which it's ideal for) - a built in PLL will generate the proper clock from the incoming signal.

For inputs, you can use classic I2S (the default) or 16-bit, 20-bit or 24-bit left justified data. You can set it up to take an

input system/master clock but we default-set it to just generate it for you, so you only need to connect Data In, Word

Select (Left/Right Clock) and Bit Clock lines. If you want, there's a mute pin and a de-emphasis filter you can turn on.

We put in plenty of ferrite beads, a low-dropout regulator, and the recommended band-pass filter so you get a very

nice clean output. With a sine-wave generator we swept through 20-20KHz and saw no attenuation or distortion. Plug

into either the 3.5mm stereo headphone jack or the breadboard-friendly pads. We think you'll be pleased with this

DAC!

Each order comes with one I2S Stereo DAC breakout and some header you can solder on.

Pinouts

The UDA1334A is an I2S amplifier - it does not use analog inputs, it only has digital audio input support! Don't confuse

I2S with I2C, I2S is a sound protocol whereas I2C is for small amounts of data.

Power Pins

The UDA1334A requires 3.3V power but can take 3-5V

level logic on nearly all pins.

You can provide 3-5V power on the VIN pin and GND

and the built in regulator will generate a nice clean 3.3V

supplier on 3VOut.

Use the quietest power supply for Vin, we do filter the

power supply, but the quieter the better!

I2S Pins

Three pins are used for stereo I2S data in. These pins

are required!

These can be 3.3-5V logic

WSEL (Word Select or Left/Right Clock) - this is the

pin that tells the DAC when the data is for the left

channel and when its for the right channel

DIN (Data In) - This is the pin that has the actual

data coming in, both left and right data are sent on

this pin, the WSEL pin indicates when left or right

is being transmitted

BCLK (Bit Clock) - This is the pin that tells the

amplifier when to read data on the data pin.

MCLK is not required to use this DAC, if you have an

MCLK pin on your audio source, leave it disconnected.

Audio Outputs

The exciting part! This is where your line level audio

comes out. We put big 47uF blocking capacitors on the

output so you can connect this to any stereo system.

AGND is a clean analog ground signal that we

recommend using as your analog reference, you'll get a

cleaner signal.

Note that this DAC was intended for use with a separate

amplifier and is rated for a 3 KΩ load. However, we've

found you

can

plug in 32Ω headphones and the output

is current-limited so it won't damage the DAC but you

will get distortions. (Powered headphones won't have

this issue)

Optional Control Pins

There are some extra configuration pins if you want to use them. They are not required for 99% of usage with an

Arduino or Teensy or Raspberry Pi. But you never know! So they are there for you. PLL and SF0 are 3.3V logic only,

the other pins are 3-5V safe.

Most of the pins have to do with changing the setup from audio mode to video mode. If you happen to want video-

mode, for synchronizing with NTSC/PAL, check the datasheet - we haven't used it for that purpose.

SCLK (Sys Clock) - Optional 27 MHz 'video mode'

ssytem clock input - by default we generate the

sysclock from the WS clock in 'audio mode' But

the UDA can also take a oscillator input on this pin

Mute - Setting this pin High will mute the output

De-Emphasis - In audio mode (which is the

default), can be used to add a de-emphasis filter.

In video mode, where the system clock is

generated from an oscillator, this is the clock

output.

PLL - sets the PLL mode, by default pulled low for

Audio. Can be pulled high or set to ~1.6V to set

PAL or NTSC video frequency

SF0 and SF1 are used to set the input data format. By

default both are pulled Low for I2S but you can change

them around for alternate formats.

See the back of the PCB for a quick reference

Assembly

Installing Standard Headers

The shield comes with 0.1" standard header.

Break apart the 0.1" header into 6 and 9-pin long pieces

and slip the short ends into the holes in the board

Make sure that all of the short parts of the header are

sticking through the two sets of pads on either side of

the board

Solder each one of the pins into the board to make a

secure connection

That's it! Move on to next page for wiring information

Raspberry Pi Wiring

if you have a Raspberry Pi and you want higher quality audio than the headphone jack can provide, I2S is a good

option! You only use 3 pins, and since its a pure-digital output, there can be less noise and interference.

This board works very well with boards that

don't

have audio like the Pi Zero and is the easiest way to get quality audio

out

Connect:

Amp Vin to Raspbery Pi 3V or 5V

Amp GND to Raspbery Pi GND

Amp DIN to Raspbery Pi #21

Amp BCLK to Raspbery Pi #18

Amp LRCLK to Raspbery Pi #19

https://adafru.it/A9T

This technique will work with any Raspberry Pi with the 2x20 connector. Older Pi 1's with a 2x13 connector do

not bring out the I2S pins as easily

Raspberry Pi Setup

Fast Install

Luckily its quite easy to install support for I2S DACs on Raspbian.

These instructions are totally cribbed from the PhatDAC instructions at the lovely folks at

Pimoroni! (https://adafru.it/nFy)

Run the following from your Raspberry Pi with Internet connectivity:

curl -sS https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/i2samp.sh | bash

We've added an extra helper systemd script that will play quiet audio when the I2S peripheral isn't in use. This

removes popping when playback starts or stops. It uses a tiny amount of CPU time (on a Pi Zero, 5%, on a Pi 2 or 3 its

negligible). You don't need this on RetroPie because it never releases the I2S device, but it's great for Raspbian.

At this time, Raspbery Pi linux kernel does not support mono audio out of the I2S interface, you can only play

stereo, so any mono audio files may need conversion to stereo!

2017-11-2 Raspbian PIXEL ('full') has broken something in volume control. I2S works, but there's no software

volume setup, if you need this, try Raspbian Lite - will try to fix as soon as we figure out why :)

You will need to reboot once installed.

After rebooting, log back in and re-run the script again...It will ask you if you want to test the speaker. Say yes and

listen for audio to come out of your speakers...

If it sounds really distorted, it could be the volume is too high. However, in order to have volume control appear in

Raspbian desktop or Retropie you must reboot a second time after doing the speaker test, with sudo reboot

Once rebooted, try running alsamixer and use arrow keys to lower the volume, 50% is a good place to start.

If you're still having audio problems, try re-running the script and saying N (disable) the /dev/zero playback service .

You can then go to the next page on testing and optimizing your setup. Skip the rest of this page on Detailed

You must reboot to enable the speaker hardware!

You must reboot *twice* to enable alsamixer volume (really!)

Installation if the script worked for you!

Detailed Install

If, for some reason, you can't just run the script and you want to go through the install by hand - here's all the steps!

Update /etc/modprobe.d (if it exists)

Log into your Pi and get into a serial console (either via a console cable, the TV console, RXVT, or what have you)

Edit the raspi blacklist with

sudo nano /etc/modprobe.d/raspi-blacklist.conf

If the file is empty, just skip this step

However, if you see the following lines:

blacklist i2c-bcm2708

blacklist snd-soc-pcm512x

blacklist snd-soc-wm8804

Update the lines by putting a # before each line

Save by typing Control-X Y <return>

Disable headphone audio (if it's set)

Edit the raspi modules list with

sudo nano /etc/modules

If the file is empty, just skip this step

However, if you see the following line:

snd_bcm2835

Put a # in front of it

and save with Control-X Y <return>

Create asound.conf file

Edit the raspi modules list with

sudo nano /etc/asound.conf

This file ought to be blank!

Copy and paste the following text into the file

pcm.speakerbonnet {

type hw card 0

}

pcm.dmixer {

type dmix

ipc_key 1024

ipc_perm 0666

slave {

pcm "speakerbonnet"

period_time 0

period_size 1024

buffer_size 8192

rate 44100

channels 2

}

ctl.dmixer {

type hw card 0

}

pcm.softvol {

type softvol

slave.pcm "dmixer"

control.name "PCM"

control.card 0

}

ctl.softvol {

type hw card 0

}

pcm.!default {

type plug

slave.pcm "softvol"

}

Adafruit UDA1334A User manual

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