============= ESP32 DevKitC ============= The `ESP32 DevKitC `_ is a development board for the ESP32 SoC from Espressif, based on a ESP-WROOM-32 module. You can find the original V2 version and the newer V4 variant. They are pin compatible. .. list-table:: :align: center * - .. figure:: esp32-core-board-v2.jpg :align: center ESP32 DevKitC/Core V2 - .. figure:: esp32-devkitc-v4-front.jpg :align: center ESP32 DevKitC V4 Features ======== - ESP32 WROOM Module - USB-to-UART bridge via micro USB port - Power LED - EN and BOOT buttons (BOOT accessible to user) - SPI FLASH (size varies according to model Serial Console ============== UART0 is, by default, the serial console. It connects to the on-board CP2102 converter and is available on the USB connector USB CON8 (J1). It will show up as /dev/ttypUSB[n] where [n] will probably be 0 (is it 1 on my PC because I have a another device at ttyUSB0). Buttons and LEDs ================ Buttons ------- There are two buttons labeled Boot and EN. The EN button is not available to software. It pulls the chip enable line that doubles as a reset line. The BOOT button is connected to IO0. On reset it is used as a strapping pin to determine whether the chip boots normally or into the serial bootloader. After reset, however, the BOOT button can be used for software input. LEDs ---- There are several on-board LEDs for that indicate the presence of power and USB activity. None of these are available for use by software. Ethernet ======== ESP32 has a 802.11 hardware MAC, so just connects to external PHY chip. Due to the limited number of GPIOs in ESP32, it's recommended to use RMII to connect to an external PHY chip. Current driver also only supports RMII option. The RMII GPIO pins are fixed, but the SMI and functional GPIO pins are optional. RMII GPIO pins are as following: ========== ============= ESP32 GPIO PHY Chip GPIO ========== ============= IO25 RXD[0] IO26 RXD[1] IO27 CRS_DV IO0 REF_CLK IO19 TXD[0] IO21 TX_EN IO22 TXD[1] ========== ============= SMI GPIO pins (default option) are as following: ========== ============= ESP32 GPIO PHY Chip GPIO ========== ============= IO18 MDIO IO23 MDC ========== ============= Functional GPIO pins(default option) are as following: ========== ============= ESP32 GPIO PHY Chip GPIO ========== ============= IO5 Reset_N ========== ============= Espressif has an `official Ethernet development board `_. This driver has been tested according to this board and ESP32 core board + LAN8720 module. If users have some issue about using this driver, please refer the upper official document, specially the issue that GPIO0 causes failing to bring the ESP32 chip up. I2S === ESP32 has two I2S peripherals accessible using either the generic I2S audio driver or a specific audio codec driver (`CS4344 `__ bindings are available at the moment). Also, it's possible to use the I2S character device driver to bypass audio systems and write directly to the I2S peripheral. .. note:: The I2S peripheral is able to work on two functional modes internally: 16 and 32-bit width. That limits using the I2S peripheral to play audio files other than 16/32 bit-widths as the internal buffer allocated for the audio content does not consider the operation modes of the peripheral. This limitation is planned to be removed soon by copying the buffers internally and making the necessary adjustments. .. note:: The above statement is not valid when using the I2S character device driver. It's possible to use 8, 16, 24, and 32-bit-widths writing directly to the I2S character device. Just make sure to set the bit-width:: $ make menuconfig -> System Type -> ESP32 Peripheral Selection -> I2S -> I2S0/1 -> Bit Witdh And make sure the data stream buffer being written to the I2S peripheral is aligned to the next boundary i.e. 16 bits for the 8 and 16-bit-widths and 32 bits for 24 and 32-bit-widths. Pin Mapping =========== .. todo:: To be updated ===== ========== ========== Pin Signal Notes ===== ========== ========== ? ? ? ===== ========== ========== Configurations ============== audio ----- This configuration uses the I2S0 peripheral and an externally connected audio codec to play an audio file streamed over an HTTP connection while connected to a Wi-Fi network. **Audio Codec Setup** The CS4344 audio codec is connected on the following pins: ========== ========== ========================================= ESP32 Pin CS4344 Pin Description ========== ========== ========================================= 0 MCLK Master Clock 4 SCLK Serial Clock 5 LRCK Left Right Clock (Word Select) 18 SDIN Serial Data In on CS4344. (DOUT on ESP32) ========== ========== ========================================= **Simple HTTP server** Prepare a PCM-encoded (`.wav`) audio file with 16 bits/sample (sampled at 8~48kHz). This file must be placed into a folder in a computer that could be accessed on the same Wi-Fi network the ESP32 will be connecting to. Python provides a simple HTTP server. `cd` to the audio file folder on the PC and run:: $ python3 -m http.server Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) Look for your PC IP address and test playing the prepared audio on your browser: .. figure:: esp32-audio-config-file.png :align: center After successfully built and flashed, connect the board to the Wi-Fi network:: $ nsh> wapi psk wlan0 mypasswd 1 $ nsh> wapi essid wlan0 myssid 1 $ nsh> renew wlan0 Once connected, open NuttX's player and play the file according to its file name and the IP address of the HTTP server:: $ nsh> nxplayer $ nxplayer> play http://192.168.1.239:8000/tones.wav efuse ----- A config with EFUSE enabled. i2schar ------- This configuration enables the I2S character device and the i2schar example app, which provides an easy-to-use way of testing the I2S peripheral (I2S0 on this example). After successfully built and flashed, run on the boards's terminal:: $ i2schar The corresponding output should show related debug informations. knsh ---- This is identical to the nsh configuration except that (1) NuttX is built as PROTECTED mode, monolithic module and the user applications are built separately and, as a consequence, (2) some features that are only available in the FLAT build are disabled. Protected Mode support for ESP32 relies on the PID Controller peripheral for implementing isolation between Kernel and Userspace. By working together with the MMU and Static MPUs of the ESP32, the PID Controller is able to restrict the application access to peripherals, on-chip memories (Internal ROM and Internal SRAM) and off-chip memories (External Flash and PSRAM). .. warning:: * The PID Controller driver is in **EXPERIMENTAL** state, so please consider the Protected Mode feature for ESP32 a **Proof-of-Concept**. * The PID Controller **does not** prevent the application from accessing CPU System Registers. mcp2515 ------- This config is used to communicate with MCP2515 CAN over SPI chip. SPI3 is used and kept with the default IOMUX pins, i.e.: ===== ======= Pin Signal ===== ======= 5 CS 18 SCK 23 MOSI 19 MISO ===== ======= The MCP2515 interrupt (INT) pin is connected to the pin 22 of the ESP32-Devkit. mmcsdspi -------- This config tests the SPI driver by connecting an SD Card reader over SPI. SPI2 is used and kept with the default IOMUX pins, i.e.: ===== ======= Pin Signal ===== ======= 15 CS 14 SCK 13 MOSI 12 MISO ===== ======= Once booted the following command is used to mount a FAT file system:: nsh> mount -t vfat /dev/mmcsd0 /mnt module ------ This config is to run apps/examples/module. mqttc ----- This configuration tests the MQTT-C publisher example. From the host, start the broker and subscribe to the :code:`test` topic. Using `mosquitto` this should be:: $ mosquitto& $ mosquitto_sub -t test From the NSH, connect to an access point:: nsh> wapi psk wlan0 mypasswd 1 nsh> wapi essid wlan0 myssid 1 nsh> renew wlan0 Publish to the broker:: nsh> mqttc_pub -h 192.168.1.11 The default behavior is to publish the message :code:`test`. The following should be outputted:: nsh> mqttc_pub -h 192.168.1.11 Success: Connected to broker! Success: Published to broker! Disconnecting from 192.168.1.11 From the host the message :code:`test` should be outputted. nsh --- Basic NuttShell configuration (console enabled in UART0, exposed via USB connection by means of CP2102 converter, at 115200 bps). ostest ------ This is the NuttX test at apps/testing/ostest that is run against all new architecture ports to assure a correct implementation of the OS. The default version is for a single CPU but can be modified for an SMP test by adding:: CONFIG_SMP=y CONFIG_SMP_NCPUS=2 CONFIG_SPINLOCK=y psram ----- This config tests the PSRAM driver over SPIRAM interface. You can use the ramtest command to test the PSRAM memory. We are testing only 64KB on this example (64 * 1024), but you can change this number to 2MB or 4MB depending on PSRAM chip used on your board:: nsh> ramtest -w 0x3F800000 65536 RAMTest: Marching ones: 3f800000 65536 RAMTest: Marching zeroes: 3f800000 65536 RAMTest: Pattern test: 3f800000 65536 55555555 aaaaaaaa RAMTest: Pattern test: 3f800000 65536 66666666 99999999 RAMTest: Pattern test: 3f800000 65536 33333333 cccccccc RAMTest: Address-in-address test: 3f800000 65536 smp --- Another NSH configuration, similar to nsh, but also enables SMP operation. It differs from the nsh configuration only in these additional settings: SMP is enabled:: CONFIG_SMP=y CONFIG_SMP_NCPUS=2 CONFIG_SPINLOCK=y The apps/testing/smp test is included:: CONFIG_TESTING_SMP=y CONFIG_TESTING_SMP_NBARRIER_THREADS=8 CONFIG_TESTING_SMP_PRIORITY=100 CONFIG_TESTING_SMP_STACKSIZE=2048 sotest ------ This config is to run apps/examples/sotest. spiflash -------- This config tests the external SPI that comes with an ESP32 module connected through SPI1. By default a SmartFS file system is selected. Once booted you can use the following commands to mount the file system:: nsh> mksmartfs /dev/smart0 nsh> mount -t smartfs /dev/smart0 /mnt Note that mksmartfs is only needed the first time. timer ----- This config test the general use purpose timers. It includes the 4 timers, adds driver support, registers the timers as devices and includes the timer example. To test it, just run the following:: nsh> timer -d /dev/timerx Where x in the timer instance. wamr_wasi_debug --------------- This config is an example to use wasm-micro-runtime. It can run both of wasm bytecode and AoT compiled modules. This example uses littlefs on ESP32's SPI flash to store wasm modules. 1. Create a littlefs image which contains wasm modules. https://github.com/jrast/littlefs-python/blob/master/examples/mkfsimg.py is used in the following example:: % python3 mkfsimg.py \ --img-filename ..../littlefs.bin \ --img-size 3080192 \ --block-size 4096 \ --prog-size 256 \ --read-size 256 \ ..../wasm_binary_directory 2. Write the NuttX image and the filesystem to ESP32:: % esptool.py \ --chip esp32 \ --port /dev/tty.SLAB_USBtoUART \ --baud 921600 \ write_flash \ 0x1000 ..../bootloader-esp32.bin \ 0x8000 ..../partition-table-esp32.bin \ 0x10000 nuttx.bin \ 0x180000 ..../littlefs.bin 3. Mount the filesystem and run a wasm module on it:: nsh> mount -t littlefs /dev/esp32flash /mnt nsh> iwasm /mnt/.... wapi ---- Enables Wi-Fi support. You can define your credentials this way:: $ make menuconfig -> Application Configuration -> Network Utilities -> Network initialization (NETUTILS_NETINIT [=y]) -> WAPI Configuration Or if you don't want to keep it saved in the firmware you can do it at runtime:: nsh> wapi psk wlan0 mypasswd 1 nsh> wapi essid wlan0 myssid 1 nsh> renew wlan0 watchdog -------- This config test the watchdog timers. It includes the 2 MWDTS, adds driver support, registers the WDTs as devices and includes the watchdog example. To test it, just run the following:: nsh> wdog -d /dev/watchdogx Where x in the watchdog instance. wifinsh ------- The ``wifinsh`` is similar to the ``wapi`` board example, but it will connect automatically to your Access Point (Wi-Fi Router) and will run telnet daemon in the board. Then you can connect to your board from your computer using the telnet program. After configuring the ``esp32-devkit:wifinsh`` you need to define your creden- tials in the menuconfig. You can define your credentials this way:: $ make menuconfig -> Application Configuration -> Network Utilities -> Network initialization (NETUTILS_NETINIT [=y]) -> WAPI Configuration Find your board IP using ``nsh> ifconfig`` and then from your computer:: $ telnet 192.168.x.y Where x and y are the last two numbers of the IP that your router gave to your board.