usb-serial | keyboard IO number | keyboard IO register -- | -- | -- 3v3 | 3 | 3v3 TXD | 16 | PA10 RXD | 15 | PA9 GND | 1 | GND USB | keyboard IO number | keyboard IO register -- | -- | -- 5v power | 5 | 5v GND | 22 | GND data + | 18 | PA12(USB_DP) data - | 17 | PA11(USB_DM) can not have USB and usb-serial both ON sudo stm32flash -r devterm.kbd.0.3_48mhz.bin -S 0x08000000:65536 /dev/ttyUSB0 srec_cat devterm.kbd.0.3_48mhz.bin -Binary -offset 0x08000000 -output devterm.kbd.0.3_48mhz.hex -Intel stm32flash -w devterm_kbd.bin -v -S 0x08000000 /dev/ttyUSB0 ![WechatIMG50](https://user-images.githubusercontent.com/523580/186061860-02efc332-eae9-4200-ae37-c312af5d0f96.jpeg)