CCpilot VA
1.2
Technical Manual
2017-03-13
www.maximatecc.com
22
5.7.
USB
CCpilot VA
has two USB ports. One port is located in the multipin connector J1 and function as a USB
host-port only. It can be used for connecting USB storage devices or other peripherals such as mouse,
keyboard or various wireless interfaces.
The second USB port support USB OTG, i.e. acting as either host or device port, and is primarily
intended for development use. It has a USB Mini-B port connector located under a sealed cover on the
back of the device, see figure below.
In USB
host-mode
(default mode), this port supports
the same functionality as the first USB host port.
USB
device-mode
is normally only used for loading
the operating system image during production or
recovery in case the internal flash storage is corrupted
to a point where self-recovery is no longer possible. It
is also possible to implement other USB device
functionality, such as
USB mass-storage
or emulating
a
USB Ethernet interface
. However, there is no build-
in software support for such USB device
implementations.
Note that the sealing property (IP classification) of the device is not retained when removing the hatch
for accessing the second USB port.
Each USB ports can supply up to 500 mA, according to the USB 2.0 specification. The USB ports are
internally over-current and short-circuit protected. Shielded cables shall be used to ensure reliable
communication and electromagnetic compliance.
Refer to
chapter 3.4.1
for recommendations about connecting shield cables.
Due to limitation in the multipin connector specification, USB data signal integrity cannot be
guaranteed at higher speeds than full-speed USB (12 Mbps). Nevertheless, hi-speed (480 Mbit/s)
operation is supported by the USB host controller and has demonstrated good stability for most
applications. Using high-quality, shielded USB cables with minimum cable length improves noise
immunity and USB stability.
