20-101-1202 Rabbit Semiconductor, 20-101-1202 Datasheet - Page 49

• Manufacturer Part Number: 20-101-1202
• Description: RCM4400W (FCC CERTIFIED)
• Manufacturer: Rabbit Semiconductor
• Type: Wi-Fi / 802.11.br

Specifications of 20-101-1202

• Frequency: 2.4GHz
• Wireless Frequency: 58.98 MHz
• Supported Devices: RAM4400W
• Tool / Board Applications: Wireless Connectivity-ZigBee, RF, Infrared, USB
• Development Tool Type: Hardware / Software - Dev Kit (Dev Tool)
• Rohs Compliant: Yes
• For Use With/related Products: RCM4400W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 316-1143

4.4 Other Hardware
4.4.1 Clock Doubler
The RCM4400W takes advantage of the Rabbit 4000 microprocessor’s internal clock
doubler. A built-in clock doubler allows half-frequency crystals to be used to reduce
radiated emissions. The 58.98 MHz frequency specified for the RCM4400W is generated
using a 29.49 MHz crystal.
The clock doubler should not be disabled since Wi-Fi operations depend highly on CPU
resources.
4.4.2 Spectrum Spreader
The Rabbit 4000 features a spectrum spreader, which helps to mitigate EMI problems. The
spectrum spreader is on by default, but it may also be turned off or set to a stronger setting.
The spectrum spreader settings may be changed through a simple configuration macro as
shown below.
OEM User’s Manual
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
normal spreading, add the line
For strong spreading, add the line
To disable the spectrum spreader, add the line
are in the project file where you defined the macro.
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
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
setting will be needed in a real application.
to save the macro. The spectrum spreader will now remain off whenever you
Options > Project Options
menu.
43