EoSim — In-Browser Board Simulator

Simulate 83 Boards
Without Hardware

Run real EoS firmware code in your browser. Toggle GPIO pins, watch UART output, and test your programs on STM32, ESP32, Raspberry Pi Pico, and more — no hardware required.

View EoSim on GitHubDocumentation
PCB Signal TracesSTM32F4 Discovery
OscilloscopeLED Blink
Target Board
Program
STM32F4 Discovery
STM32F407VGT6
ARM Cortex-M4
Clock
168 MHz
Flash
1 MB
RAM
192 KB
GPIO Pins
Click OUTPUT pins to toggle
led_blink.c
Toggles an output pin at 1 Hz
// EoS LED Blink — runs on every supported board
#include <eos/gpio.h>
#include <eos/time.h>

int main(void) {
    eos_gpio_set_mode(PIN_0, GPIO_OUTPUT);
    eos_log("EoSim: LED blink started");

    while (1) {
        eos_gpio_write(PIN_0, GPIO_HIGH);
        eos_log("PIN_0 → HIGH");
        eos_delay_ms(500);

        eos_gpio_write(PIN_0, GPIO_LOW);
        eos_log("PIN_0 → LOW");
        eos_delay_ms(500);
    }
}
UART / Serial Output
IDLE
Press Run to start simulation…
83 Supported Boards
STM32, ESP32, Raspberry Pi Pico, RISC-V, nRF52, i.MX RT, and more — all simulated in-browser.
Real EoS API Surface
Programs use the same eos/gpio.h, eos/uart.h, and eos/time.h headers as production firmware.
HIL Bridge Support
Connect EoSim to real hardware via the HIL bridge for hardware-in-the-loop testing workflows.