All the USART, SPI and I2C pins are rearranged for easy usage. This board has got the standard FTDI board connector so that a FTDI basic board or a FTDI USB to Serial converter can be directly connected to for easy programming. The analog pins (ADC) and the PWM pins as well as the 5 volt tolerant pins of the Blue Pill board has been also marked.
The DC jack can be used to connect power from a battery or an adapter to this board. The on board voltage regulator converts the input voltage to 3.3 volt that is needed to run the BluePill board.