101-0523 Rabbit Semiconductor, 101-0523 Datasheet - Page 34

• Manufacturer Part Number: 101-0523
• Description: KIT DEV RABBIT3000/RCM3000
• Manufacturer: Rabbit Semiconductor
• Series: RabbitCore 3000r
• Type: MPU Moduler

Specifications of 101-0523

• Rohs Status: RoHS non-compliant
• Contents: RabbitCore Module, Dev. Board, AC Adapter, Cable and Dynamic C® CD-Rom
• Processor To Be Evaluated: RCM3000
• Interface Type: RS-232, Ethernet
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: - 40 C
• Operating Supply Voltage: 3.15 V to 3.45 V
• For Use With/related Products: RCM3000
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 316-1017

4.4 Other Hardware
4.4.1 Clock Doubler
The RCM3000 takes advantage of the Rabbit 3000 microprocessor’s internal clock dou-
bler. A built-in clock doubler allows half-frequency crystals to be used to reduce radiated
emissions. The 29.4 MHz frequency specified for the RCM3000 is generated using a
14.7456 MHz crystal. The clock doubler will not work for crystals with a frequency
above 26.7264 MHz.
The clock doubler may be disabled if 29.4 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.
26
1. Select the “Defines” tab from the Dynamic C
2. Add the line
3. Click
1.
2. Normal spreading is the default, and usually no entry is needed. If you need to specify nor-
3.
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.
Select the “Defines” tab from the Dynamic C Options > Project Options menu.
mal spreading, add the line
For strong spreading, add the line
To disable the spectrum spreader, add the line
Click OK to save the macro. The spectrum spreader will now remain off 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 not recommended since it may limit
OK
on the spectrum-spreading setting 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 whenever you are
CLOCK_DOUBLED=0
to always disable the clock doubler.
Options > Project Options
CLOCK_DOUBLED=1
RabbitCore RCM3000
menu.
to