122-32000 Parallax Inc, 122-32000 Datasheet - Page 137

• 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

In
cycles” to “delay in milliseconds.” Compile and download the Blinker2 object now. Notice
that the rate at which each LED blinks is the same as it was when we used the internal fast
clock. Try increasing the clock speed by changing
PLL16X
clock frequency by four!
Keep in mind that the accuracy of the internal clock on your particular Propeller chip can
play a big role in the way this example looks, especially when using the
There are two techniques for using the
them. For further tips regarding timing, see the
Quick Review: Ex 9 & 10
Main
•
•
. You should not see any change in the blink rates even though we just multiplied the
, we adjusted the second parameter of the all the calls to
Clock:
Timing:
o The internal clock has two speeds, slow (≈ 20 KHz) and fast (≈ 12 MHz).
o To specify clock settings for an application, the top object file sets values for
o Whenever external crystals or clocks are used, either
o
o
o
o Use the internal clock for convenience where accuracy doesn’t matter. Use
o Subordinate objects can’t rely on a specific, hard-coded time-base since
o Use the
one or more special constants:
must be specified in addition to
_CLKMODE
settings, etc. See
_XINFREQ
See
_CLKFREQ
an external clock for accuracy or when the phase-locked loop (PLL) is
needed.
applications which use them may change the clock frequency.
Hertz for timing calculations. See
_XINFREQ
CLKFREQ
specifies the System Clock frequency. See
specifies the frequency coming into the XI pin (Crystal Input pin).
specifies the clock mode: internal/external, oscillator gain, PLL
, page 337.
_CLKMODE
command to get the current System Clock frequency in
WAITCNT
, page 180.
_CLKMODE
WAITCNT
_CLKMODE
command but we only demonstrated one of
CLKFREQ
_CLKMODE
,
command on page 322.
_CLKFREQ
.
, page 175.
from
Propeller Manual v1.0 · Page 137
Start
and
XTAL1 + PLL4X
_CLKFREQ
_XINFREQ
_XINFREQ
RCSLOW
from “delay in clock
, page 177.
mode.
.
or
to
_CLKFREQ
XTAL1 +