122-32000 Parallax Inc, 122-32000 Datasheet - Page 337

• Manufacturer Part Number: 122-32000
• Description: MANUAL PROPELLER
• Manufacturer: Parallax Inc

Specifications of 122-32000

• Accessory Type: Manual
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

_XINFREQ
Pre-defined, one-time settable constant for specifying the external crystal frequency.
CON
Explanation
_XINFREQ
determine the System Clock frequency at start-up. It is a pre-defined constant symbol whose
value is determined by the top object file of an application.
the application itself, or is set indirectly as the result of the
The top object file in an application (the one where compilation starts from) can specify a
setting for
that the System Clock will switch to as soon as the application is booted up and execution
begins.
The application can specify either
exclusive and the non-specified one is automatically calculated and set as a result of
specifying the other.
The following examples assume that they are contained within the top object file. Any
_XINFREQ
For example:
The first declaration in the above
crystal and a Clock PLL multiplier of 8. The second declaration indicates the external crystal
frequency is 4 MHz, which means the System Clock’s frequency will be 32 MHz because 4
MHz * 8 = 32 MHz. The
declarations.
_XINFREQ = Expression
•
Expression
frequency on the XI pin. This value is used for application start-up.
CON
specifies the external crystal frequency, which is used along with the clock mode to
settings in child objects are simply ignored by the compiler.
_CLKMODE = XTAL1 + PLL8X
_XINFREQ = 4_000_000
_XINFREQ
is an integer expression that indicates the external crystal frequency; the
in its
CON
_CLKFREQ
block. This, along with the clock mode, defines the frequency
_XINFREQ
CON
4: Spin Language Reference –
value is automatically set to 32 MHz because of these
block sets the clock mode for an external low-speed
or
_CLKFREQ
in the
_CLKMODE
_XINFREQ
Propeller Manual v1.0 · Page 337
CON
and
block; they are mutually
is either set directly by
_CLKFREQ
settings.