The STM32F411CEU6 Black Pill is built around STMicroelectronics’ STM32F411CEU6 MCU. It offers significantly more performance than the older STM32F103 “Blue Pill,” while keeping a similar small, breadboard‑friendly form factor. 
Key MCU Specifications
CPU: ARM Cortex‑M4 @ 100 MHz with FPU & DSP instructions  
Flash: 512 KB
SRAM: 128 KB
Voltage: 1.7–3.6 V (board logic 3.3 V)
ADC: 1× 12‑bit ADC (up to 2.4 MSPS)
Timers: Up to 11 (16‑bit & 32‑bit)
Interfaces:
3× I²C
3× USART
Multiple SPI/I²S
SDIO
USB 2.0 FS OTG with on‑chip PHY (supports DFU bootloader) 
The board exposes two 20‑pin headers (≈33 GPIO pins). Common default peripheral mappings (Arduino STM32 core):
I²C: PB6/PB7
SPI: PA5 (SCK), PA6 (MISO), PA7 (MOSI), PA4 (SS)
UART: PA9/PA10
USB: PA11/PA12 (USB FS