ESP32-S3 / ESP32 Boards
madflight for ESP32-S3/ESP32 requires Arduino-ESP32 v3.x.x
madflight v1.1.2 and earlier requires Arduino-ESP32 v2.x.x
Start the Arduino IDE and select menu Tools->Board Manager to install this software.
Pinout ESP32-S3-DevKitC-1
This is the default pinout for ESP32-S3. It is optimized for the Espressif ESP32-S3-DevKitC-1 (44 pin) board. This pinout is defined in madflight_board_default_ESP32-S3.h, but can be modified with #define HW_PIN_XXX in your program.
NOTE: Many clones of this board exist, which use various ESP32-S3-VROOM modules and/or have different on-board hardware (LED, RGB LED, SDCARD, etc.) Set Arduino IDE Board settings and HW_PIN_XXX defines accordingly.
Note: Pin numbers refer to the GPIO numbers, not to the physical pin number on a board.
| Function | GPIO | Board | GPIO | Function |
|---|---|---|---|---|
| 3V3 out | 3V3 | Antenna | G | GND |
| 3V3 out | 3V3 | 43 | TX serial debug UART port | |
| reset button | RST | 44 | RX serial debug UART port | |
| PWM1 | 4 | 1 | - | |
| PWM2 | 5 | 2 | LED (not on all boards) | |
| PWM3 | 6 | 42 | - | |
| PWM4 | 7 | 41 | - | |
| PWM5 | 15 | 40 | SD_MMC_DATA | |
| PWM6 | 16 | 39 | SD_MMC_CLK | |
| RCIN_TX | 17 | 38 | SD_MMC_CMD | |
| RCIN_RX | 18 | 37 | PSRAM (on boards with Octal PSRAM) | |
| I2C_SDA | 8 | 36 | PSRAM (on boards with Octal PSRAM) | |
| GPS_RX | 3 | 35 | PSRAM (on boards with Octal PSRAM) | |
| GPS_TX | 46 | 0 | boot button | |
| I2C_SCL | 9 | 45 | - | |
| IMU_CS | 10 | 48 | RGB_LED | |
| SPI_MOSI | 11 | 47 | - | |
| SPI_MISO | 12 | 21 | - | |
| SPI_SCLK | 13 | 20 | USB_D+ (serial debug alternate) | |
| IMU_EXTI | 14 | 19 | USB_D- (serial debug alternate) | |
| 5V in (*) | 5V | G | GND | |
| GND | G | USB connectors | G | GND |
(*) 5V input via diode from BEC. Without a diode take care not connect USB and the battery at the same time!
Setup ESP32-S3 in the Arduino IDE
In the Aduino IDE select board: "ESP32S3 Dev Module" and set the following options in the Tools menu:
- Flash Mode: see table below
- Flash Size: see x in table below
- PSRAM: see table below
| ESP32-S3 module | Flash Mode | PSRAM | Notes |
|---|---|---|---|
| ESP32-S3-WROOM-1-Nx | QIO 80MHz | - | |
| ESP32-S3-WROOM-1-Hx | QIO 80MHz | - | High temperature version |
| ESP32-S3-WROOM-1-NxR2 | QIO 80MHz | QSPI PSRAM | |
| ESP32-S3-WROOM-1-NxR8 | QIO 80MHz | QSPI PSRAM | pins IO35, IO36, and IO37 are connected to the Octal SPI PSRAM and are not available |
| for other uses. | |||
| ESP32-S3-WROOM-1-NxR16V | QIO 80MHz | OPI PSRAM | 1.8V SPI, pins IO35, IO36, and IO37 are connected to the Octal SPI PSRAM and are not available |
| for other uses. | |||
| ESP32-S3-WROOM-2-NxR8V | OPI 80MHz | OPI PSRAM | 120MHz SPI, 1.8V SPI, pins IO35, IO36, and IO37 are connected to the Octal SPI PSRAM and are not available |
| for other uses. |
Setup Serial Port
Settings for 3 serial ports (Serial, Serial1 and Serial2), Serial connected to "USB-UART", Serial0 not connected (gives error 'Serial0' was not declared).
- USB CDC On Boot: Disabled
Settings for 4 serial ports (Serial, Serial0, Serial1 and Serial2), Serial connected to "USB-OTG", Serial0 connected to "USB-UART"
- USB CDC On Boot: Enabled
- USB DFU On Boot: Disabled
- USB Mode: USB-OTG (TinyUSB)
Setup Programming Interface
Settings for programming via "USB-UART" usb port (programming works without pressing boot/reset buttons)
- Upload Mode: UART0 / Hardware CDC
Settings for programming via "USB-OTG" usb port (For programming: press boot, press+release reset, release boot, then upload; For serial monitor: press+release reset, then open serial monitor)
- Upload Mode: USB-OTG CDC (TinyUSB)
Pinout ESP32 DevKitC
This is the default pinout for ESP32. It is optimized for the Espressiv ESP32 DevKitC (38 pin) board. This pinout is defined in madflight_board_default_ESP32.h, but can be modified with #define HW_PIN_XXX in your program.
Many clones of this board exist, which might have different ESP32 modules and/or different on-board hardware (LED, RGB LED, SDCARD, etc.) Set Arduino IDE Board settings and HW_PIN_XXX defines accordingly.
| Function | GPIO | Board | GPIO | Function |
|---|---|---|---|---|
| 3V3 out | 3V3 | Antenna side | GND | GND |
| reset button | EN | 23 | I2C_SDA | |
| SPI_MISO | VP 36 input only | 22 | I2C_SCL | |
| IMU_EXTI | VN 39 input only | 1 TX | USB Serial Debug TX | |
| BAT_V | 34 input only | 3 RX | USB Serial Debug RX | |
| RCIN_RX | 35 input only | 21 | SPI_MOSI | |
| RCIN_TX | 32 | GND | GND | |
| PWM1 | 33 | 19 | SPI_SCLK | |
| PWM2 | 25 | 18 | IMU_CS | |
| PWM3 | 26 | strap 5 | GPS_TX | |
| PWM4 | 27 | 17 | GPS_RX | |
| PWM5 | 14 | 16 | PWM11 | |
| PWM6 | 12 | 4 | PWM10 | |
| GND | GND | boot 0 | PWM9 | |
| PWM7 | 13 | strap 2 | LED | |
| nc | D2 9 flash | strap 15 | PWM8 | |
| nc | D3 10 flash | flash 8 D1 | nc | |
| nc | CMD 11 flash | flash 7 D0 | nc | |
| 5V input (*) | 5V | USB connector | flash 6 CLK | nc |
(*) 5V input via diode from BEC. Without a diode take care not connect USB and the battery at the same time!
Note: During boot the input voltage levels (pull up/pull down) on strap pins have a configuration function, therefor these pins are used as output only.
ESP32 has 6 strapping pins: - GPIO0: internal pull-up (boot button) - GPIO2: internal pull-down - GPIO4: internal pull-down - GPIO5: internal pull-up - GPIO12: internal pull-down - GPIO15: internal pull-up
ESP32-S3/ESP32 Hardware
ESP32-S3 and ESP32 are very similar chips. The ESP32-S3 is more recent: it has more pins, USB-OTG (3 UARTs plus 1 USB-OTG CDC UART), improved single block RAM structure. The ESP32 is better if you need a lot of PWM channels, it has 16 PWM (LEDC) outputs, versus 8 on ESP32-S3.
Dual Core / FPU
ESP32 and ESP32-S3 both have dual core CPU, but single core FPU. ESP-IDF implementation limits float usage to a single core, and float can not be used in interrupts. FreeRTOS is always enabled and a watchdog limits interrupt execution time.
madflight uses float and is therefor limited to single core operation. The IMU loop runs as a high priorty task, triggered by the IMU interrupt.
FreeRTOS
FreeRTOS is enabled by default.
I2C
Arduino-ESP32 v2.0.17 has an I2C bug which causes the bus to hang for 1 second after a failed read, which can happen a couple times per minute. This makes Wire I2C for IMU not a real option...
A workaround is to use #define USE_ESP32_SOFTWIRE which enables software I2C, but this does not work well with all sensors.
(!) So, until a better I2C solution is available: use an SPI IMU sensor on ESP32.
NOTE: as of June 2024 this bug is apparently fixed, but not yet confirmed with madflight.