#Add up to three USB 2.0 host ports

The signals of three USB 2.0 host ports are wired on J4 pads but some
of them are already used so it is possible to use them only 
in specific situations. 
The signals of the __USB port A__ are wired to the microUSB connector 
so it is possible to use them only when the microUSB port is not used 
or not plugged on a PC. 
The signals of the __USB port B__ are wired to the WiFi port so it is
possible to use them only when the WiFi adapter is not 
plugged on Arietta. 

<img src="./arietta_usb.jpg"/>

<center markdown="1">

| Line  | Signal   | Speed | Notes                                         |
|-------|----------|-------|-----------------------------------------------|
| J4.4  | USB A D- | High  | Don't use if the microUSB data lines are used |
| J4.6  | USB A D+ | High  | Don't use if the microUSB data lines are used |
| J4.16 | USB B D+ | High  | Don't use if the WiFi module is mounted       |
| J4.18 | USB B D- | High  | Don't use if the WiFi module is mounted       |
| J4.20 | USB C D- | Full  |                                               |
| J4.22 | USB C D+ | Full  |                                               |

</center>

@shop='USBCON-1'
@shop='USBCON-2'
@shop='USBCON-3'