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ESP32 Specs: Pins, Cores, and Limits
The numbers everyone asks about: cores, pins, GPIO, I2C device counts, and how many volts the ESP32 can take — with the caveats the datasheet leaves out.
How Many Cores Does ESP32 Have?
The classic ESP32 (the WROOM-32) has two 240MHz Xtensa cores. The S3 also has two (faster LX7 cores); the C3, C6, and H2 have one RISC-V core; the P4 has two. So how many cores does esp32 have depends on which esp32 you mean — the name is a family, not one chip.
How Many Pins Does ESP32 Have?
The WROOM-32 module exposes 38 pads, but the dev board in your hand may show 30 or 38 pins depending on the clone — both are the same chip, and the 30-pin version just leaves some pads unconnected. So how many pins in esp32 depends on the form factor: chip 48 pads, module 38, board 30 or 38.
How Many GPIO Pins Does ESP32 Have?
34 on the classic WROOM-32 — but free ones number closer to 25: six go to the flash chip, GPIO 34–39 are input-only, and a few conflict with PSRAM on WROVER modules. A practical budget is 25–28 pins, and the S3 and C3 differ — every answer to how many gpio pins does esp32 have should start with “which chip”.
How Many Digital Pins in ESP32?
All 34 GPIO are digital-capable — that’s what a GPIO is — so the count matches the question above: 34, minus the flash-claimed six and the four input-only ones. Eighteen pins also read analog across two ADC units, and any pin outputs PWM via LEDC. One official quirk: the ADC2 unit stops working while Wi-Fi transmits.
How Many I2C Devices Can Be Connected to ESP32?
No fixed number — I2C is a bus, and the limit is electrical, not logical. 127 addresses exist, but real-world loading from wires, pull-ups, and capacitance typically caps you at 10–20 sensors. The ESP32 has two I2C controllers, and the GPIO matrix puts either one on nearly any pins. The official docs are vague here, so test your actual string.
How Many Volts Can ESP32 Handle?
The chip itself is strict: 3.0–3.6V on any pin, nothing more. The board around it is more forgiving — VIN accepts 5V on every devkit (that’s what USB provides), and some regulators tolerate up to 12V, though that’s manufacturer-dependent and I wouldn’t push past 6V. Never feed 5V into a GPIO — the classic board-killer. One line: 3.3V logic, 5V to VIN, nothing else.
How much RAM and flash does it have?
520KB SRAM and 4MB of flash on the standard WROOM-32; the flash also holds your program and files. WROVER modules and S3 variants add PSRAM (2–8MB) for big buffers like camera frames. At 240MHz dual-core, 520KB is plenty for most IoT work — you’ll feel it only when stacking TLS, a camera, and a web server. Full specs are in the knowledge base.
How many timers does the ESP32 have?
Four 64-bit hardware timers on the classic chip, plus a system timer per core and a low-power RTC timer that keeps counting in deep sleep. For PWM, the LEDC peripheral provides 16 channels, and FreeRTOS layers software timers on top; you’ll run out of peripherals before timers.
What’s the fastest the ESP32 can run?
240MHz on the classic and S3 chips, 160MHz on the C3, and you can clock down to save power — down to 80MHz or even 10MHz on some variants. Overclocking past 240 works on good silicon but generates heat for little real gain. My C3 sits at 160MHz without complaint, though I’ve seen reports of instability on budget boards.
What are the ESP32’s real-world limits?
Flash endurance (about 100,000 erase cycles per sector — log to SD or NVS carefully), Wi-Fi range (tens of meters indoors), and peak current (roughly 300mA while transmitting). None bite typical projects, but all three show up as mysterious failures if unplanned. The power FAQ covers batteries; the Wi-Fi FAQ covers range.
Specs You Can Watch Execute
The numbers in this FAQ have faces: run classic, C3, S3 and each chip signs its own Serial banner. Dual core, RISC-V, LX7 — the taxonomy becomes three tabs you have open simultaneously, not a table you memorized.