238 lines
7.5 KiB
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238 lines
7.5 KiB
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================
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ESP32-S2-Saola-1
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================
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The `ESP32-S2-Saola-1 <https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/hw-reference/esp32s2/user-guide-saola-1-v1.2.html>`_
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is a development board for the ESP32-S2 SoC from Espressif, based on the following modules:
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- ESP32-S2-WROVER
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- ESP32-S2-WROVER-I
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- ESP32-S2-WROOM
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- ESP32-S2-WROOM-I
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In this guide, we take ESP32-S2-Saola-1 equipped with ESP32-S2-WROVER as an example.
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.. figure:: esp32-s2-saola-1-v1.2-isometric.png
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:alt: ESP32-S2-Saola-1
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:figclass: align-center
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ESP32-S2-Saola-1
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Features
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========
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- ESP32-S2-WROVER
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- 4 MB external SPI flash + 2 MB PSRAM
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- USB-to-UART bridge via micro USB port
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- Power LED
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- EN and BOOT buttons
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- RGB LED (Addressable RGB LED (WS2812), driven by GPIO18)
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Serial Console
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==============
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UART0 is, by default, the serial console. It connects to the on-board
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CP2102 converter and is available on the micro-USB connector (J1).
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It will show up as /dev/ttyUSB[n] where [n] will probably be 0.
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Buttons and LEDs
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================
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Buttons
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-------
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There are two buttons labeled Boot and EN. The EN button is not available
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to the software. It pulls the chip enable line that doubles as a reset line.
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The BOOT button is connected to IO0. On reset, it is used as a strapping
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pin to determine whether the chip boots normally or into the serial
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bootloader. After resetting, however, the BOOT button can be used for
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software input.
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LEDs
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----
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There are two on-board LEDs. RED_LED (D5) indicates the presence of 3.3V
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power and is not controlled by software. RGB LED (U6) is a WS2812 addressable
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LED and is driven by GPIO18.
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I2S
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===
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ESP32-S2 has an I2S peripheral accessible using either the generic I2S audio
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driver or a specific audio codec driver
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(`CS4344 <https://www.cirrus.com/products/cs4344-45-48/>`__ bindings are
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available at the moment). The generic I2S audio driver enables using both
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the receiver module (RX) and the transmitter module (TX) without using any
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specific codec. Also, it's possible to use the I2S character device driver
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to bypass the audio subsystem and write directly to the I2S peripheral.
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.. note:: When using the audio system, sample rate and data width are
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automatically set by the upper half audio driver.
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.. note:: The above statement is not valid when using the I2S character
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device driver.
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It's possible to use 8, 16, 24, and 32-bit-widths writing directly to the
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I2S character device. Just make sure to set the bit-width::
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$ make menuconfig
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-> System Type
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-> ESP32-S2 Peripheral Selection
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-> I2S
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-> Bit Witdh
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The following configurations use the I2S peripheral::
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* :ref:`platforms/xtensa/esp32s2/boards/esp32s2-saola-1/index:audio`
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* :ref:`platforms/xtensa/esp32s2/boards/esp32s2-saola-1/index:i2schar`
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* :ref:`platforms/xtensa/esp32s2/boards/esp32s2-saola-1/index:nxlooper`
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Configurations
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==============
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audio
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-----
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This configuration uses the I2S peripheral and an externally connected audio
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codec to play an audio file. The easiest way of playing an uncompressed file
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is embedding into the firmware. This configuration selects
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`romfs example <https://github.com/apache/nuttx-apps/tree/master/examples/romfs>`__
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to allow that.
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**Audio Codec Setup**
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The CS4344 audio codec is connected to the following pins:
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============ ========== =========================================
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ESP32-S2 Pin CS4344 Pin Description
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============ ========== =========================================
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33 MCLK Master Clock
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35 SCLK Serial Clock
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34 LRCK Left Right Clock (Word Select)
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36 SDIN Serial Data In on CS4344. (DOUT on ESP32)
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============ ========== =========================================
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**ROMFS example**
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Prepare and build the `audio` defconfig::
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$ make -j distclean && ./tools/configure.sh esp32s2-saola-1:audio && make
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This will create a temporary folder in `apps/examples/romfs/testdir`. Move
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a PCM-encoded (`.wav`) audio file with 16 or 24 bits/sample (sampled at 16~48kHz)
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to this folder.
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.. note:: You can use :download:`this 440 Hz sinusoidal tone <tone.wav>`.
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The audio file should be located at `apps/examples/romfs/testdir/tone.wav`
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Build the project again and flash it (make sure not to clean it, just build)
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After successfully built and flashed, load the romfs and play it::
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$ nsh> romfs
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$ nsh> nxplayer
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$ nxplayer> play /usr/share/local/tone.wav
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i2schar
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-------
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This configuration enables the I2S character device and the i2schar example
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app, which provides an easy-to-use way of testing the I2S peripheral,
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enabling both the TX and the RX for those peripherals.
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**I2S pinout**
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============ ========== =========================================
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ESP32-S2 Pin Signal Pin Description
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============ ========== =========================================
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33 MCLK Master Clock
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35 SCLK Bit Clock (SCLK)
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34 LRCK Word Select (LRCLK)
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36 DOUT Data Out
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37 DIN Data In
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============ ========== =========================================
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After successfully built and flashed, run on the boards's terminal::
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nsh> i2schar
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The corresponding output should show related debug information.
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nsh
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---
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Basic NuttShell configuration (console enabled in UART0, exposed via
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USB connection by means of CP2102 converter, at 115200 bps).
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nxlooper
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--------
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This configuration uses the I2S peripheral as an I2S receiver and
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transmitter at the same time. The idea is to capture an I2S data frame
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using the RX module and reproduce the captured data on the TX module.
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**Receiving and transmitting data on I2S**
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The I2S will act as a receiver (master mode), capturing data from DIN, which
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needs to be connected to an external source as follows:
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============ ========== =========================================
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ESP32-S2 Pin Signal Pin Description
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============ ========== =========================================
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33 MCLK Master Clock
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35 SCLK Bit Clock (SCLK) Output
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34 LRCK Word Select (LRCLK) Output
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36 DOUT Data Out
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37 DIN Data In
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============ ========== =========================================
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The DOUT pin will output the captured data frame.
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.. note:: The ESP32-S2 contains a single I2S peripheral, so the peripheral
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works on "full-duplex" mode. The `SCLK` and `LRCK` signals are connected
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internally and the TX module is set-up as slave and the RX as master.
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**nxlooper**
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The `nxlooper` application captures data from the audio device with receiving
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capabilities and forwards the audio data frame to the audio device with
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transmitting capabilities.
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After successfully built and flashed, run on the boards's terminal::
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nsh> nxlooper
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nxlooper> loopback
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.. note:: `loopback` command default arguments for the channel configuration,
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the data width and the sample rate are, respectively, 2 channels,
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16 bits/sample and 48KHz. These arguments can be supplied to select
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different audio formats, for instance::
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nxlooper> loopback 2 8 44100
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timer
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-----
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This config tests the general-use purpose timers. It includes the 4 timers,
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adds driver support, registers the timers as devices and includes the timer
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example.
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To test it, just run the following::
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nsh> timer -d /dev/timerx
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Where x in the timer instance.
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watchdog
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--------
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This config test the watchdog timers. It includes the 2 MWDTs,
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adds driver support, registers the WDTs as devices and includes the watchdog
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example.
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To test it, just run the following::
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nsh> wdog -i /dev/watchdogx
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Where x is the watchdog instance.
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