If your board doesn't have a USB connector connected to the USB-OTG dedicated GPIOs, you may have to DIY a cable and connect **D+** and **D-** to the pins listed below.
```
ESP BOARD USB CONNECTOR (type A)
--
| || VCC
[USBPHY_DM_NUM] ------> | || D-
[USBPHY_DP_NUM] ------> | || D+
| || GND
--
```
Refer to `soc/usb_pins.h` to find the real GPIO number of **USBPHY_DP_NUM** and **USBPHY_DM_NUM**.