101-1279 Rabbit Semiconductor, 101-1279 Datasheet - Page 33

• Manufacturer Part Number: 101-1279
• Description: PLASTIC ENCLOSURE FOR BL4S100
• Manufacturer: Rabbit Semiconductor

Specifications of 101-1279

• Accessory Type: Enclosure
• Product: Prototyping Accessories
• Processor Type: BL4S100
• Board Size: 146 mm x 96 mm x 16 mm
• Interface Type: Ethernet
• For Use With/related Products: BL4S100
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 316-1159

3.6 Other Hardware
3.6.1 Clock Doubler
The BL4S100 takes advantage of the Rabbit microprocessor’s internal clock doubler. A
built-in clock doubler allows half-frequency crystals to be used to reduce radiated emissions.
The clock doubler may be disabled if the higher clock speeds are not required. Disabling
the clock doubler will reduce power consumption and further reduce radiated emissions.
The clock doubler is disabled with a simple configuration macro as shown below.
3.6.2 Spectrum Spreader
The Rabbit microprocessors features a spectrum spreader, which help to mitigate EMI
problems. By default, the spectrum spreader is on automatically, but it 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.
BL4S100 User’s Manual
1. Select the “Defines” tab from the Dynamic C
2. Add the line
3. Click
1. Select the “Defines” tab from the Dynamic C
2. Normal spreading is the default, and usually no entry is needed. If you need to specify nor-
3. Click
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
always enable the clock doubler.
your setting whenever you are using the project file where you defined the macro.
mal spreading, add the line
For strong spreading, add the line
To disable the spectrum spreader, add the line
value whenever a program is compiled using this project file.
ENABLE_SPREADER=1
ENABLE_SPREADER=2
ENABLE_SPREADER=0
NOTE: Refer to the Rabbit 4000 Microprocessor User’s Manual for more information
NOTE: The strong spectrum-spreading setting is not recommended since it may limit
OK to save
OK
on the spectrum-spreading settings and the maximum clock speed.
the maximum clock speed or the maximum baud rate. It is unlikely that the strong set-
ting will be used in a real application.
to save the macro. The clock doubler will now remain off or on according to
CLOCK_DOUBLED=0
the macro. The spectrum spreader will be set according to the macro
to always disable the clock doubler.
Options > Project Options menu.
Options > Project Options
CLOCK_DOUBLED=1
menu.
to
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