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diff --git a/examples/Readme.txt b/examples/Readme.txt new file mode 100644 index 0000000..25f8c55 --- /dev/null +++ b/examples/Readme.txt @@ -0,0 +1,101 @@ +This is the Readme file for the directory "examples" of AVR-USB, a firmware- +only USB driver for AVR microcontrollers. + +WHAT IS IN THIS DIRECTORY? +========================== +This directory contains examples which are mostly for educational purposes. +Examples can be device firmware only, host software only or both. Here is +a summary: + +custom-class + A custom class device with host software based on libusb. It demonstrates + the straight forward way of sending small amounts of data to a device and + receiving data from the device. It does NOT demonstrate how to send large + amounts of data to the device or how to receive data generated on the fly + by the device (how to use usbFunctionWrite() and usbFunctionRead()). See + the hid-data example for how usbFunctionWrite() and usbFunctionRead() are + used. + +hid-custom-rq + This example implements the same functionality as the custom-class example + above, but declares the device as HID. This prevents the "give me a driver + CD" dialog on Windows. The device can still be controlled with libusb as in + the previous example (on Windows, the filter version of libusb-win32 must + be installed). In addition to the features presented in custom-class, this + example demonstrates how a HID class device is defined. + +hid-mouse + This example implements a mouse device. No host driver is required since + today's operating systems have drivers for USB mice built-in. It + demonstrates how a real-world HID class device is implemented and how + interrupt-in endpoints are used. + +hid-data + This example demonstrates how the HID class can be misused to transfer + arbitrary data over HID feature reports. This technique is of great value + on Windows because no driver DLLs are needed (the hid-custom-rq example + still requires the libusb-win32 DLL, although it may be in the program's + directory). The host side application requires no installation, it can + even be started directly from a CD. This example also demonstrates how + to transfer data using usbFunctionWrite() and usbFunctionRead(). + +usbtool + This is a general purpose development and debugging tool for USB devices. + You can use it during development of your device to test various requests + without special test programs. But it is also an example how all the + libusb API functions are used. + +More information about each example can be found in the Readme file in the +respective directory. + +Hardware dependencies of AVR code has been kept at a minimum. All examples +should work on any AVR chip which has enough resources to run the driver. +Makefile and usbconfig.h have been configured for the metaboard hardware (see +http://metalab.at/wiki/Metaboard for details). Edit the target device, fuse +values, clock rate and programmer in Makefile and the I/O pins dedicated to +USB in usbconfig.h. + + +WHAT IS NOT DEMONSTRATED IN THESE EXAMPLES? +=========================================== +These examples show only the most basic functionality. More elaborate +examples and real world applications showing more features of the driver are +available at http://www.obdev.at/avrusb/projects.html. Most of these +features are described in the Documentation Wiki linked from this page. + +To mention just a few: + +Using RC oscillator for system clock + The 16.5 MHz module of AVR-USB has been designed to cope with clock rate + deviations up to 1%. This allows an RC oscillator to be used. Since the + AVR's RC oscillator has a factory precision of only 10%, it must be + calibrated to an external reference. The EasyLogger example shows how this + is done. + +Dynamically generated descriptors + Sometimes you want to implement different typtes of USB device depending + on a jumper or other condition. AVR-USB has a very flexible interface for + providing USB descriptors. See AVR-Doper for how to provide descriptors + at runtime. + +Virtual COM port + Some people prefer a virtual serial interface to communicate with their + device. We strongly discourage this method because it does things + forbidden by the USB specification. If you still want to go this route, + see AVR-CDC. + +Implementing suspend mode + AVR-USB does not implement suspend mode. This means that the device does + not reduce power consumption when the host goes into sleep mode. Device + firmware is free to implement suspend mode, though. See USB2LPT for an + example. + +The projects mentioned above can best be found on + + http://www.obdev.at/avrusb/prjall.html + +where all projects are listed. + +---------------------------------------------------------------------------- +(c) 2008 by OBJECTIVE DEVELOPMENT Software GmbH. +http://www.obdev.at/ |