Difference: I2SAndSound (1 vs. 2)

Revision 22021-01-24 - UliRaich

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META TOPICPARENT	name="Exercises"

I2S and sound

Introduction

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the PCM5102a, a stereo converter board with a connector for head phones. If we want to connect a loudspeaker to this board we have to pass through an audio amplifier.

Connecting the MAX98357A

Added:

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>

Here is a table showing how I connected the MAX98357A to the ESP32 board:

MAX98357A pin

pin on ESP32 CPU card

signification

Changed:

<
<

GND

>
>

Gnd

Vcc	3.3V
SD	n.c.

Changed:

<
<

Gain

GND

>
>

Gain

Gnd

important: don't leave this pin floating!

Din	D2: GPIO 21	audio data
BCLK	D3: GPIO 17	bit clock

Changed:

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<

RC (LRCLK)

D1: GPIO

left/right clock

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>

LRC (LRCLK)

D1: GPIO 22

left/right clock

Connecting the PCM5102:

Added:

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>

PCM5102 pin	pin on ESP32 CPU card	signification
Vcc	3.3V
Gnd	Gnd
BCK	D3: GPIO 17	bit clock
Din	D2: GPIO 21	audio data
Lck (LRCLK)	D1: GPIO 22	left/right clock
FMT	Gnd
Xmt	Vcc

Uli Raich - 2021-01-24

Comments

Line: 35 to 47

META FILEATTACHMENT	attachment="max98357a.png" attr="" comment="" date="1611505403" name="max98357a.png" path="max98357a.png" size="208396" user="UliRaich" version="1"
META FILEATTACHMENT	attachment="pcm5102.png" attr="" comment="" date="1611505405" name="pcm5102.png" path="pcm5102.png" size="130048" user="UliRaich" version="1"

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META FILEATTACHMENT	attachment="pcm5102back.png" attr="" comment="" date="1611510513" name="pcm5102back.png" path="pcm5102back.png" size="90367" user="UliRaich" version="1"

Revision 12021-01-24 - UliRaich

Line: 1 to 1

Added:

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META TOPICPARENT	name="Exercises"

I2S and sound

Introduction

In order to play audio files we need:

the audio file itself, which we expect to be in uncompressed wav format
a file system from which to read the file. This is available in MicroPython either in its internal flash or on an SD card
a fast 16 bit DAC to convert the audio data into an analogue form that can be consumed by a loadspeaker
an amplifier to get enough signal power needed for the loadspeaker
a software driver implementing the I2S protocol

The digital data must be transferred to the DAC, which is done through the I2S protocol

invented by Philips in the end 1980 ies.

There are two cheap I2S boards converting digital audio data to an analogue audio signal and communicating through the I2S protocol:

the ! MAX98357A, a mono converter board with integrated amplifier to which we can directly connect a loadspeaker
the PCM5102a, a stereo converter board with a connector for head phones. If we want to connect a loudspeaker to this board we have to pass through an audio amplifier.

Connecting the MAX98357A

Here is a table showing how I connected the MAX98357A to the ESP32 board:

MAX98357A pin	pin on ESP32 CPU card	signification
GND	GND
Vcc	3.3V
SD	n.c.
Gain	GND
Din	D2: GPIO 21	audio data
BCLK	D3: GPIO 17	bit clock
RC (LRCLK)	D1: GPIO	left/right clock

-- Uli Raich - 2021-01-24

Comments

<--/commentPlugin-->

META FILEATTACHMENT	attachment="max98357a.png" attr="" comment="" date="1611505403" name="max98357a.png" path="max98357a.png" size="208396" user="UliRaich" version="1"
META FILEATTACHMENT	attachment="pcm5102.png" attr="" comment="" date="1611505405" name="pcm5102.png" path="pcm5102.png" size="130048" user="UliRaich" version="1"

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