Release Notes for USB Firmware Reference Projects,
Microchip Technology Inc.

19 November 2004

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1. Reference Projects are setup to be used with a bootloader
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When opening an example, always open the workspace file (*.mcw)

All examples in this directory except 'Boot' have been setup to
work with a bootloader.

Basic Assumptions:

* The bootloader has remapped the reset and interrupt vectors to
  address 0x0800,0x0808, and 0x0818.

* A modified linker script file with a boot section is used.
  The file is rm18f4550.lkr, and is located in each example's directory.

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If you have an ICD2 and are not planning to use the bootloader, you
must do the following modifications to each project:

1. In the MPLAB project, change the rm18f4550.lkr to a standard
   18f4550.lkr, which can be found in the default C18 lkr directory.

2. Update the default linker path in MPLAB by clicking on
   Project\Build Options...\Project, click on the 'General' tab
   and update the linker path to use the C18 default linker directory.

3. Remove the following code from the Vector Remapping Section:

   extern void _startup (void); // See c018i.c in your C18 compiler dir
   #pragma code _RESET_INTERRUPT_VECTOR = 0x000800
   void _reset (void)
   {
       _asm goto _startup _endasm
   }
   #pragma code

   The Vector Remapping section is typically found in main.c.

4. This step is optional. Disable the Table Write Protect Boot.
   In MPLAB, click Configure\Configuration Bits...
   Under address 0x30000B, disable Table Write Protect Boot.

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2. Programming a different hex file using the bootloader
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Each project's hex file can be found in the '_output' directory,
i.e. CDC\_output, Demo\_output.

* Launch PDFSUSB.exe
* Hold down push button S2 and connect the demo board to a PC to
  enter Bootload mode
* Click 'Load HEX File' to select a hex file from an '_output' directory
* Click 'Program Device'
* Reset the demo board to run the new program

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