Source: https://mokxi.com/stm32-simulator
Updated: 2026-09-27

Simulator

# STM32 simulator, running in this tab

Mokxi is a free STM32 simulator that runs in your browser, with nothing to install and no account needed. Mokxi models the STM32F411 on the WeAct "Black Pill", on our own Cortex-M4 core at 84 MHz, on the real memory map, so a build that runs here runs on the board on your desk.

Sign up free or see the full STM32 board page

- 192 parts on the bench
- 25 boards running now
- 1.00x real time, on every board

Click to open it in the editor

Real firmware, running right now on our own core. Click it to open the circuit in the editor.

What is modeled

## The numbers, not the marketing

Taken from the board's own contract document and put in plain words.

The core

Cortex-M4 (ARMv7-M), no FPU, at 84 MHz, with the datasheet cycle count of every instruction.

Peripherals

GPIO on ports A to C with the real MODER, OTYPER, PUPDR and BSRR registers, TIM2 to TIM5 with glitch-free PWM, USART1, and SysTick with the real NVIC priority bits.

What is not there yet

The ADC, DMA, I2C, SPI and USB, and the clock tree: SYSCLK is fixed at 84 MHz from power-on rather than brought up from HSI and the PLL.

Go further

## The full board page

Every peripheral area, every example and the wiring notes, in one place.

STM32F411 simulator Blink, a button and the serial monitor, running.

## Questions

Which STM32 does this simulate?

The STM32F411CEU6, on the WeAct "Black Pill" v3.x.

Will my firmware run on a real Black Pill?

Yes, as long as it does not reach for the ADC, DMA, I2C, SPI or USB.

Does it run the STM32Cube HAL?

No. The firmware runtime here is ours, not the vendor HAL, libopencm3 or the STM32duino core.

Is it free?

Yes, with no card and no account needed to try it.

## Try your own firmware on the STM32

What you build here runs on the board on your desk, unchanged. Nothing to install and no account needed.

Start building Open the editor