101-0566 Rabbit Semiconductor, 101-0566 Datasheet - Page 40

• Manufacturer Part Number: 101-0566
• Description: COMPUTER SNGLBD BL2100 FRCTNLOCK
• Manufacturer: Rabbit Semiconductor

Specifications of 101-0566

• Module/board Type: Single Board Computer Module
• For Use With/related Products: BL2100
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

3.9.2 Clock Doubler
The BL2100 takes 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 emis-
sions. 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.
3.9.3 Spectrum Spreader
BL2100 boards that carry the CE mark on their RabbitCore module have a Rabbit 2000
microprocessor that features a spectrum spreader, which helps to mitigate EMI problems.
By default, the spectrum spreader is on automatically for BL2100 boards that carry the CE
mark when used with Dynamic C 7.30 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 BL2100 boards that do not carry the CE
mark on their RabbitCore module or when using any BL2100 with a version of Dynamic C
prior to 7.30.
34
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 be set to the state specified by
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 macro value whenever you are in 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 BL2000.
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
Smartcat (BL2100)
menu.