Makefiles and library modified to add a new F_CLOCK constant to give the unprescaled...

[pub/lufa.git] / LUFA / GettingStarted.txt

diff --git a/LUFA/GettingStarted.txt b/LUFA/GettingStarted.txt
index 0fe3f50..a88a825 100644 (file)
--- a/LUFA/GettingStarted.txt
+++ b/LUFA/GettingStarted.txt
@@ -57,14 +57,22 @@
  *  directory into a /Board/ folder inside the application directory, and the stub driver completed with the appropriate code to drive the\r
  *  custom board's hardware.\r
  *\r
- *  \subsection SSec_F_CPU The F_CPU Parameter\r
- *  This parameter indicates the target AVR's master clock frequency, in Hz. Consult your AVR model's datasheet for allowable clock frequencies\r
- *  if the USB interface is to be operational.\r
+ *  \subsection SSec_F_CLOCK The F_CLOCK Parameter\r
+ *  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\r
+ *  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\r
+ *  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.\r
  *\r
- *  <b>Note that this value does not actually *alter* the AVR's clock frequency</b>, it is just a way to indicate to the library the clock frequency\r
+ *  <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\r
  *  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\r
  *  library components will ocurr.\r
  *\r
+ *  \subsection SSec_F_CPU The F_CPU Parameter\r
+ *  This parameter indicates the target AVR's master CPU clock frequency, in Hz.\r
+ *\r
+ *  <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\r
+ *  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\r
+ *  library components will ocurr.\r
+ *\r
  *  \subsection SSec_CDEFS The CDEFS Parameter\r
  *  Most applications will actually have multiple CDEF lines, which are concatenated together with the "+=" operator. This ensures that large\r
  *  numbers of configuration options remain readable by splitting up groups of options into seperate lines.\r