101-0394 Rabbit Semiconductor, 101-0394 Datasheet - Page 41

• Manufacturer Part Number: 101-0394
• Description: CARD D/A +/-10V SR9410 SMARTSTAR
• Manufacturer: Rabbit Semiconductor

Specifications of 101-0394

• Accessory Type: Smart Star D/A Card
• For Use With/related Products: SR9410
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

3.4 Other Hardware
3.4.1 Clock Doubler
The Smart Star CPU cards take advantage of the Rabbit 2000 microprocessor’s internal
clock doubler. A built-in clock doubler allows half-frequency crystals to be used to reduce
radiated emissions. The 22.1 MHz frequency is generated using an 11.0592 MHz crystal.
The clock doubler is disabled automatically in the BIOS for crystals with a frequency
above 12.9 MHz.
The clock doubler may be disabled if 22.1 MHz clock speeds are not required. Disabling
the Rabbit 2000 microprocessor’s internal clock doubler will reduce power consumption
and further reduce radiated emissions. The clock doubler is disabled with a simple config-
uration macro as shown below.
3.4.2 Spectrum Spreader
Smart Star CPU cards that carry the CE mark have a Rabbit 2000 microprocessor that fea-
tures a spectrum spreader, which helps to mitigate EMI problems. By default, the spectrum
spreader is on automatically for CPU cards that carry the CE mark when used with Dynamic C
7.32 or later versions, but the spectrum spreader may also be turned off or set to a stronger
setting. The means for doing so is through a simple configuration macro as shown below.
.
There is no spectrum spreader functionality for Smart Star CPU cards that do not carry the
CE mark or when using any CPU card with a version of Dynamic C prior to 7.30.
User’s Manual
1.
2. Add the line
3. Click
1. Select the “Defines” tab from the Dynamic C Options > Project Options menu.
2. Normal spreading is the default, and usually no entry is needed. If you need to specify normal
3. Click OK to save the macro. The spectrum spreader will now remain off whenever you are in
Select the “Defines” tab from the Dynamic C Options > Project Options
The clock doubler is enabled by default, and usually no entry is needed. If you need to specify
that the clock doubler is always enabled, add the line CLOCK_DOUBLED=1
the clock doubler. The clock speed will be doubled as long as the crystal frequency is
less than or equal to 26.7264 MHz.
project file where you defined the macro.
spreading, add the line
For strong spreading, add the line
To disable the spectrum spreader, add the line
the project file where you defined the macro.
ENABLE_SPREADER=1
ENABLE_SPREADER=2
ENABLE_SPREADER=0
NOTE: The strong spectrum-spreading setting is unnecessary for the Smart Star.
OK to save the macro. The clock doubler will now remain off whenever you are in the
CLOCK_DOUBLED=0 to always disable the clock doubler.
to always enable
menu.
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