LUFA/ManPages/ConfiguringApps.txt

   1 /** \file
   2  *
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   6
   7 /** \page Page_ConfiguringApps Configuring the Demos, Bootloaders and Projects
   8  *
   9  *  If the target AVR model, clock speed, board or other settings are different to the current settings, they must be changed
  10  *  and the project recompiled from the source code before being programmed into the AVR microcontroller. Most project
  11  *  configuration options are located in the "makefile" build script inside each LUFA application's folder, however some
  12  *  demo or application-specific configuration settings (such as the output format in the AudioOut demo) are located in the
  13  *  main .c source file of the project. See each project's individual documentation for application-specific configuration
  14  *  values.
  15  *
  16  *  Each project "makefile" contains all the script and configuration data required to compile each project. When opened with
  17  *  any regular basic text editor such as Notepad or WordPad (ensure that the save format is a pure ASCII text format) the
  18  *  build configuration settings may be altered.
  19  *
  20  *  Inside each makefile, a number of configuration variables are located, with the format "<VARIABLE NAME> = <VALUE>". For
  21  *  each application, the important variables which should be altered are:
  22  *
  23  *    - <b>MCU</b>, the target AVR processor.
  24  *    - <b>BOARD</b>, the target board hardware
  25  *    - <b>F_CLOCK</b>, the target raw master clock frequency, before any prescaling is performed
  26  *    - <b>F_CPU</b>, the target AVR CPU master clock frequency, after any prescaling
  27  *    - <b>CDEFS</b>, the C preprocessor defines which configure the source code
  28  *
  29  *  These values should be changed to reflect the build hardware.
  30  *
  31  *  \section Sec_MCU The MCU Parameter
  32  *  This parameter indicates the target AVR model for the compiled application. This should be set to the model of the target AVR
  33  *  (such as the AT90USB1287, or the ATMEGA32U4), in all lower-case (e.g. "at90usb1287"). Note that not all demos support all the
  34  *  USB AVR models, as they may make use of peripherals or modes only present in some devices.
  35  *
  36  *  For supported library AVR models, see main documentation page.
  37  *
  38  *  \section Sec_BOARD The BOARD Parameter
  39  *  This parameter indicates the target AVR board hardware for the compiled application. Some LUFA library drivers are board-specific,
  40  *  such as the LED driver, and the library needs to know the layout of the target board. If you are using one of the board models listed
  41  *  on the main library page, change this parameter to the board name in all UPPER-case.
  42  *
  43  *  If you are not using any board-specific drivers in the LUFA library, or you are using a custom board layout, change this to read
  44  *  "USER" (no quotes) instead of a standard board name. If the USER board type is selected and the application makes use of one or more
  45  *  board-specific hardware drivers inside the LUFA library, then the appropriate stub drives files should be copied from the /BoardStubs/
  46  *  directory into a /Board/ folder inside the application directory, and the stub driver completed with the appropriate code to drive the
  47  *  custom board's hardware.
  48  *
  49  *  \section Sec_F_CLOCK The F_CLOCK Parameter
  50  *  This parameter indicates the target AVR's input clock frequency, in Hz. This is the actual clock input, before any prescaling is performed. In the
  51  *  USB AVR architecture, the input clock before any prescaling is fed directly to the PLL subsystem, and thus the PLL is derived directly from the
  52  *  clock input. The PLL then feeds the USB and other sections of the AVR with the correct upscaled frequencies required for those sections to function.
  53  *
  54  *  <b>Note that this value does not actually *alter* the AVR's input clock frequency</b>, it is just a way to indicate to the library the clock frequency
  55  *  of the AVR as set by the AVR's fuses. If this value does not reflect the actual running frequency of the AVR, incorrect operation of one of more
  56  *  library components will occur.
  57  *
  58  *  \section Sec_F_CPU The F_CPU Parameter
  59  *  This parameter indicates the target AVR's master CPU clock frequency, in Hz.
  60  *
  61  *  <b>Note that this value does not actually *alter* the AVR's CPU clock frequency</b>, it is just a way to indicate to the library the clock frequency
  62  *  of the AVR core as set by the AVR's fuses. If this value does not reflect the actual running frequency of the AVR, incorrect operation of one of more
  63  *  library components will occur.
  64  *
  65  *  \section Sec_CDEFS The CDEFS Parameter
  66  *  Most applications will actually have multiple CDEF lines, which are concatenated together with the "+=" operator. This ensures that large
  67  *  numbers of configuration options remain readable by splitting up groups of options into separate lines.
  68  *
  69  *  Normally, these options do not need to be altered to allow an application to compile and run correctly on a different board or AVR to the
  70  *  current configuration - if the options are incorrect, then the demo is most likely incompatible with the chosen USB AVR model and cannot be
  71  *  made to function through the altering of the makefile settings alone (or at all). Settings such as the USB mode (device, host or both), the USB
  72  *  interface speed (Low or Full speed) and other LUFA configuration options can be set here - refer to the library documentation for details on the
  73  *  configuration parameters.
  74  */