BL4S200 User’s Manual
47
3.8 Other Hardware
3.8.1 Clock Doubler
The BL4S200 Ethernet models and the Wi-Fi model (BL4S200, BL4S210, and BL5S220)
take 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 on the BL4S230 is disabled by default.
The clock doubler may be disabled on the BL4S200 Ethernet models (BL4S200 and
BL4S210)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.
NOTE:
Do not disable the clock doubler on the Wi-Fi model (BL5S220) since Wi-Fi
operations depend highly on the CPU resources.
1. Select the “Defines” tab from the Dynamic C
Options > Project Options
menu.
2. Add the line
CLOCK_DOUBLED=0
to always disable the clock doubler.
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
CLOCK_DOUBLED=1
to
always enable the clock doubler.
3. Click
OK
to save the macro. The clock doubler will now remain off whenever you are
in the project file where you defined the macro.
electronic components distributor
