This demo board contains a 250 MHz STM32H503RBT6 Arm Cortex-M33 MCU with 128KB Flash and 32KB RAM.
PB14 USART1 TX ARDUINO D1 TX PB15 USART1 RX ARDUINO D0 RX PA3 USART3 RX VCP RX PA4 USART3 TX VCP TX
PC13 BUTTON PA5 LED GREEEN
LSE X2 32.768 KHz HSE X3 NX2016SA 24 MHz