20-101-1217 Rabbit Semiconductor, 20-101-1217 Datasheet - Page 41

• Manufacturer Part Number: 20-101-1217
• Description: MODULE RABBITCORE RCM3229
• Manufacturer: Rabbit Semiconductor

Specifications of 20-101-1217

• Module/board Type: MPU Core Module
• For Use With/related Products: RCM3229
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 316-1146

4.4 Other Hardware
4.4.1 Clock Doubler
The RCM3200 takes advantage of the Rabbit 3000 microprocessor’s internal clock doubler.
A built-in clock doubler allows half-frequency crystals to be used to reduce radiated emis-
sions. The 44.2 MHz frequency specified for the RCM3200 and the RCM3220 is gener-
ated using a 22.12 MHz resonator.
The clock doubler may be disabled if 44.2 MHz clock speeds are not required. Disabling
the Rabbit 3000 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.
4.4.2 Spectrum Spreader
The Rabbit 3000 features a spectrum spreader, which helps 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.
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
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.
in the project file where you defined the macro.
normal spreading, add the line
For strong spreading, add the line
To disable the spectrum spreader, add the line
by 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: Refer to the Rabbit 3000 Microprocessor User’s Manual for more information
NOTE: The strong spectrum-spreading setting is unnecessary for the RCM3200.
OK
OK
on the spectrum-spreading setting and the maximum clock speed.
to save the macro. The spectrum spreader will now be set to the state specified
to save the macro. The clock doubler will now remain off whenever you are
CLOCK_DOUBLED=0
to always disable the clock doubler.
Options > Project Options
Options > Project Options
CLOCK_DOUBLED=1
menu.
menu.
to
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