updated README.md

drivers/usermode-sdk/README.md

-Introduction
-============
+# Introduction
 
-RoboPeak Mini USB Display is a low cost display module with USB connectivity for data
-transmission and designed by RoboPeak Team. It can be convenient used as a Human
-Interactive Interface device for various embedded devices and platforms.
+RoboPeak Mini USB Display is a low cost display module with USB connectivity for
+data transmission and designed by RoboPeak Team. It can be convenient used as a
+Human Interactive Interface device for various embedded devices and platforms.
 
-Resources
-=========
+# Resources
+We provides documents, precompiled ROMs and any related materials at the product
+page of our document wiki:
+http://www.robopeak.com/docs/doku.php?id=product-rpusbdisp
 
-We provided
\ No newline at end of file
+# User Mode SDK
+User mode sdk is a set of libraries and APIs used to enable RoboPeak Mini USB
+Display without flashing the firmware of your device or installing driver (Driver
+is still needed by Windows platform).
+
+If you are using display with Windows, OS X, please use this SDK.
+
+If you don't or not be allowed to recompile the kernel or install kernel module, please use this SDK.
+
+If you want more control over the display, please use this SDK.
+
+# Build
+We provided makefiles as well as IDE project files to easily build the SDK.
+
+## Windows
+Please ensure you have Visual Studio 2013 (or Express) installed. Just open
+the project file located at workspaces/vs2013, and build like any other visual
+studio projects.
+
+## OS X (Mac OS X)
+Just open the xcode project in workspaces/xcode with latest Xcode and build.
+
+## Linux
+Just run make in this directory, to build the SDK. We use some C++ 11 features
+(mutex, thread, functional, memory, and etc.), so you may need GCC 4.8 to build
+this SDK.
+
+# APIs
+Both C++ and C APIs are provided. You may choose to your own flavour. They provide
+the same features.
+
+## C++ APIs
+### Headers
+```c++
+#include <rp/infra_config.h> // The configuration of infra
+#include <rp/drivers/display/rpusbdisp/rpusbdisp.h> // The RoboPeak USB Display
+
+// In order to simplify the sample, we use the following namesapces
+using namespace std;
+using namespace rp::deps::libusbx_wrap;
+using namespace rp::drivers::display;
+```
+
+### Open Device
+Devices need to be open before use.
+
+#### Easy Way
+You can just use a shortcut to open the first
+available device connected to your computer (this is very useful if you only want
+to use one display):
+```c++
+shared_ptr<RoboPeakUsbDisplayDevice> device = RoboPeakUsbDisplayDevice::openFirstDevice();
+```
+
+#### More Flexible Way
+You can also enumerate devices and open device by yourself
+```c++
+// Enumerate devices
+vector<shared_ptr<Device>> usbDevices = RoboPeakUsbDisplayDevice::enumDevices();
+
+shared_ptr<Device> usbDevice = pick_device(usbDevices);
+
+shared_ptr<RoboPeakUsbDisplayDevice> device = make_shared<RoboPeakUsbDisplayDevice>(usbDevice->openDevice());
+```
+
+### Device Operation APIs
+Please refer to the rpusbdisp-drv/include/rp/drivers/display/rpusbdisp/rpusbdisp.h for all paint APIs provided by the SDK
+
+## C APIs
+### Headers
+```c
+#include <rp/infra_config.h>
+#include <rp/drivers/display/rpusbdisp/c_interfaces.h>
+```
+
+The usage of C APIs is similar to the C++ API, please refer to the rpusbdisp-drv/include/rp/drivers/display/rpusbdisp/c_intefaces.h for detailed information
+
+# Demo
+A demo is included in this SDK to demonstrate the usage of the SDK which is organised in the demo directory