ESP32-WROVER

make flash BOARD=board-esp32-wrover

Feature: board-esp32-wrover. Manifest: board/src/esp32_wrover.rs.

SoC: ESP32 — see ESP32 for the full pin table and peripheral map. Tick: 1 ms.

Never flashed. The manifest is written and its invariant tests pass, but nobody has held the hardware. This used to be the default board, which meant make flash with no argument built for the least tested board in the tree; there is no default any more. The verified board is the DevKitC / WROOM-32.

Same silicon and same image format, so this should work. If you have one, please report either way — bringing up the WROOM-32 found two real bugs in a day, both of which had passed every host test.

The WROVER difference

GPIO16 and GPIO17 are PSRAM. The module carries 4–8 MB of external PSRAM wired to those two pins. Using them for anything else breaks it.

That also means UART2’s native pads are gone on this board — U2RXD/U2TXD are 16/17. Route UART2 through the GPIO matrix to other pins if you need it.

Everything else matches a plain ESP32 module.

What the manifest wires up

Bus	Peripheral	Pins	Speed
uart0	UART0	TX 1, RX 3	115200 8N1
spi3	SPI3 / VSPI	MOSI 23, MISO 19, SCK 18	40 MHz, Mode 0
i2c0	I2C0	SDA 21, SCL 22	400 kHz

Device	Driver	Bus	CS
temp_sensor	bme280	spi3	GPIO15
display	ssd1306	i2c0	—

The VSPI pins are IO_MUX-native, so that bus bypasses the GPIO matrix.

The BME280 and SSD1306 are dev-board wiring, not onboard parts. If your WROVER board doesn’t have them attached, those entries do nothing.

Free pins

Safe to use, after the reservations above:

4, 12, 13, 14, 25, 26, 27, 32, 33 and input-only 34, 35, 36, 39.

Careful with 0, 2, 5, 12, 15 — strapping pins. GPIO12 especially: pulling it high at boot sets the flash voltage wrong and can brick the module.

Never 6–11 (SPI flash) or 16, 17 (PSRAM).

Flashing

Standard USB serial. If it fails, see Troubleshooting.