This file documents changes in the firmware-only USB driver for atmel's AVR
microcontrollers. New entries are always appended to the end of the file.
Scroll down to the bottom to see the most recent changes.

2005-04-01:
  - Implemented endpoint 1 as interrupt-in endpoint.
  - Moved all configuration options to usbconfig.h which is not part of the
    driver.
  - Changed interface for usbVendorSetup().
  - Fixed compatibility with ATMega8 device.
  - Various minor optimizations.

2005-04-11:
  - Changed interface to application: Use usbFunctionSetup(), usbFunctionRead()
    and usbFunctionWrite() now. Added configuration options to choose which
    of these functions to compile in.
  - Assembler module delivers receive data non-inverted now.
  - Made register and bit names compatible with more AVR devices.

2005-05-03:
  - Allow address of usbRxBuf on any memory page as long as the buffer does
    not cross 256 byte page boundaries.
  - Better device compatibility: works with Mega88 now.
  - Code optimization in debugging module.
  - Documentation updates.

2006-01-02:
  - Added (free) default Vendor- and Product-IDs bought from voti.nl.
  - Added USBID-License.txt file which defines the rules for using the free
    shared VID/PID pair.
  - Added Readme.txt to the usbdrv directory which clarifies administrative
    issues.

2006-01-25:
  - Added "configured state" to become more standards compliant.
  - Added "HALT" state for interrupt endpoint.
  - Driver passes the "USB Command Verifier" test from usb.org now.
  - Made "serial number" a configuration option.
  - Minor optimizations, we now recommend compiler option "-Os" for best
    results.
  - Added a version number to usbdrv.h

2006-02-03:
  - New configuration variable USB_BUFFER_SECTION for the memory section where
    the USB rx buffer will go. This defaults to ".bss" if not defined. Since
    this buffer MUST NOT cross 256 byte pages (not even touch a page at the
    end), the user may want to pass a linker option similar to
    "-Wl,--section-start=.mybuffer=0x800060".
  - Provide structure for usbRequest_t.
  - New defines for USB constants.
  - Prepared for HID implementations.
  - Increased data size limit for interrupt transfers to 8 bytes.
  - New macro usbInterruptIsReady() to query interrupt buffer state.
