2,Support ISP and JTAG.
3,All the IO port are leaded out, including the PA, PB, PC, PD ports.
4,On-board an programmable indicator.
5,On-board AMS1117-3.3 power chip, provides 800mA maximum current.
6,On-board Mini USB interface, 5V power supply, capacitor filter, chip operating voltage can choose to work at 3.3V or 5V.