20-101-0522 Rabbit Semiconductor, 20-101-0522 Datasheet - Page 19

• Manufacturer Part Number: 20-101-0522
• Description: MODULE RABBITCORE RCM3220
• Manufacturer: Rabbit Semiconductor

Specifications of 20-101-0522

• Module/board Type: MPU Core Module
• Product: Microcontroller Modules
• Core Processor: Rabbit 3000
• Clock Speed: 44.2 MHz
• Interface Type: Ethernet, Serial
• Flash: 512 KB
• Timers: 10 x 8 bit, 1 x 10 bit
• Operating Supply Voltage: 3.15 V to 3.45 V
• Board Size: 69 mm x 47 mm x 22 mm
• Core: RCM3220
• Processor Series: RCM3200
• For Use With/related Products: RCM3220
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 316-1098

2.4 Other Hardware
2.4.1 Clock Doubler
The RCM3200 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 44.2 MHz frequency specified for the RCM3200 is generated 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 change
to the BIOS as described below.
2.4.2 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 change to the following BIOS
line in a way that is similar to the clock doubler described above.
User’s Manual
1. Open the BIOS source code file,
2. Change the line
3. Save the change using
to read as follows.
#define ENABLE_SPREADER 1
#define SPREADER_SETTING 0 // 0 = normal spreading, 1 = strong spreading
#define CLOCK_DOUBLED 1 // set to 1 to double clock if
#define CLOCK_DOUBLED 0
NOTE: Refer to the Rabbit 3000 Microprocessor User’s Manual for more information
on the spectrum-spreading setting and the maximum clock speed.
File > Save
// Rabbit 2000: crystal <= 12.9024 MHz,
// Rabbit 3000: crystal <= 26.7264 MHz,
// or to 0 to always disable clock doubler
RABBITBIOS.C
// Set to 0 to disable spectrum spreader.
.
in the
BIOS
directory.
15