STM32 Black Pill as drawn on the Velxio canvas

STM32 Black Pill Simulator
Cortex-M4 with FPU, the usual step up from a Blue Pill

Simulate the STM32 Black Pill (STM32F411CE, Cortex-M4 with FPU) in your browser: Arduino C++ through the STM32duino core on QEMU, GPIO, I2C, SPI and UART on a live canvas, OLED and sensor examples included.

Run a STM32 Black Pill example →Pin map and docs

Three free 15-minute trial sessions · Then Maker and Pro plans · Runs in your browser

STM32 Black Pill at a glance

The Black Pill is an STM32F411CE: a Cortex-M4 with a floating-point unit at 100 MHz, 128 KB of RAM and 512 KB of flash, noticeably more headroom than a Blue Pill and the usual next step up. Velxio emulates it under QEMU with the real STM32duino core, so the same sketch that runs on your desk runs here, OLED over I2C included.

Processor: STM32F411CE, Arm Cortex-M4F at 100 MHz
Memory: 128 KB SRAM · 512 KB flash
Emulation: QEMU (libqemu-arm) on Velxio's servers
Languages: Arduino C++ (STM32duino core)
Made by: STMicroelectronics (STM32F411CE)
Plan: Trial, then Maker or Pro

What you can do with the STM32 Black Pill simulator

The board on the canvas is the real thing as far as your code is concerned: the same pins, the same buses, the same peripherals, wired to the same 100+ sensors, displays and actuators every other Velxio board talks to.

Arduino C++ sketches

Write a sketch in the Monaco editor with library completion, compile it against the board's own Arduino core and run the real firmware binary. The Serial Monitor is the USB port.

GPIO, PWM and ADC

Drive LEDs, relays and servos, read buttons and potentiometers, dim with PWM. Every pin follows the board's real pin map, so what works here works on the hardware.

I2C, SPI and UART

Talk to OLEDs, IMUs, ADCs, RTCs and SD cards over the buses the board really has. Bus traffic runs through emulated peripherals, not through a shortcut.

Serial Monitor

USB CDC serial reaches the Serial Monitor at the sketch's baud rate, with input, timestamps and a plotter.

Multi-board canvas

Mix this board with an Arduino, an ESP32 or a Pico on the same canvas and let them talk over serial or I2C, each running its own firmware.

Try it before you subscribe

A free account gets three 15-minute trial sessions on this board family; every run inside a session is free. Unlimited runs are part of the Maker and Pro plans and of Velxio Desktop.

STM32 Black Pill examples

Ready-to-run projects for this board from the gallery. Open one, read the sketch, press Run.

All 2 examples in the gallery →

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Frequently asked questions

What is the difference between the Black Pill F411 and F401 in the simulator?: Both share the footprint and the API. The F411CE runs at up to 100 MHz with 128 KB of RAM; the F401CE at 84 MHz with 96 KB. Both are modeled, so confirm the marking on your board and pick that page.
Does the FPU work?: Yes. Floating-point code compiles for the Cortex-M4F and runs on the emulated core; there is no software emulation of float math.
What does the STM32 simulator cost?: The editor is free, and any account can place the board and wire a circuit. Running it boots a QEMU guest on Velxio's servers: a free account gets three 15-minute trial sessions on the STM32 family, and unlimited runs are part of the Maker and Pro plans.
Is the STM32 Black Pill simulator free?: Partly. You can build and save a STM32 Black Pill circuit with any account, and a free account gets three 15-minute trial sessions to run it; every run inside a session is free. Unlimited runs boot a Linux guest on our servers, so they are part of the Maker and Pro plans, or of Velxio Desktop with a paid licence.
Which languages can I use on the STM32 Black Pill?: Arduino C++ (STM32duino core). The language is switched from the toolbar; the circuit on the canvas stays the same.

Ready to simulate the STM32 Black Pill?

Open the editor, place the STM32 Black Pill from the picker, wire what you need and press Run.

Launch the STM32 Black Pill simulator →

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