Freescale Freedom Development Board FRDM-CR20A User’s Guide, Rev. 0, 04/2015
12
Freescale Semiconductor, Inc.
FRDM-CR20A development board
4.2.4
FRDM-CR20A peripheral functions
The FRDM-CR20A development board includes the Freescale Freedom board headers enabling interface
to general purpose functions to assist with to assist with application implementations. The FRDM-CR20A
board also has alternate port functions routed to those interface headers where off-board Freescale
Freedom development platform peripherals can be used if desired.
4.2.4.1
RGB LED
The LED feature includes an RGB (Red, Green, Blue) LED. The RGB LED is driven by the MCU on
another board and not the transceiver, and therefore can be used with any application.
Figure 9
shows the
RGB circuit, The RGB LED circuity offers the following features:
•
RGB power supply is P3V3_BRD
•
GPIO driven, externally by J4 Header, J4-4 Blue, J4-5 Green, J4-6 Red
•
Optionally a 0 ohm resistor can be populated (R22-R24) and be driven by GPIO6 - 8 of the
transceiver
Figure 9. RGB LED feature
4.2.4.2
Push buttons
Push buttons can be used by the application to trigger events and are normally driven by an external MCU
or transceiver IC.
Figure 10
shows the push buttons circuit implementation.
•
No power supply is required, however a pull-up circuit is feasible.
•
Connected to the D4 and D3 signals of connector J1 for interface to off-board circuitry.
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