User manual

GHI Electronics,LLC Embedded Master User Manual
Hardware and Software Library
inserted and detected on your .Net Micro Framework device. Refer to USB Host section.
Similar to SD cards, the user would be interest in mounting / unmounting the file system on
the USB drive automatically when a USB drive is inserted or ejected. To do this, you can
get events from Embedded Master about connection / disconnection of USB devices and
call mount, unmount appropriately.
For reference documentation on how to use the storage devices with the file system,
please refer to examples in the SDK and the library documentation for:
GHIElectronics.System.IO.PersistentStorage
11.14. USB Hosting and Peripherals
Note: USB Device and USB Host are completely different tasks. A USB device is simpler,
for example, Embedded Master can simulate a USB Mouse or Storage Device when
plugged to a PC. On the other hand, USB Hosting is much more complicated. This is
where Embedded Master plays the PC role and you can connect USB mice, thumb drives
and other devices to Embedded Master.
GHI Electronics is a world leader in using USB hosting on little embedded systems. Many
“smart” chipsets and modules have been available for years that allow users to access
USB devices.
Many designers confuse USB when it comes to host and device. USB Host is the master
of the bus where all the work is done. USB devices are very simple compared to host and
they can only connect/communicate with a host and not another devices.
Usually, the host is a PC running a complex operating system (Windows, Linux, Mac...etc.)
and that system takes care of all the Host work. Embedded Master contains a full USB
host stack. With simple managed calls to the GHI library, users can communicate with
many USB devices. Some devices are even handled on a higher level where all the work
is done internally such as USB Memory Storage devices. When a memory device is
plugged in, users can write/read files without knowing anything about USB, similar to how
it works on PCs. This is all done with the built in FAT File System.
PIN# TFT# Name Description
29 29 USB_HOST_DP USB Host Data Plus
15 15 USB_HOST_DM USB Host Data Minus
19 19 USB_PWR_EN USB Power enable. To enable 5V power
for USB devices. (Currently not
supported)
20 20 USB_POWR_RD USB Power read. Connect to 5V of USB
device power. Used to detect 5V
availability.
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