Freescale Freedom Development Board FRDM-CR20A User’s Guide, Rev. 0, 04/2015
Freescale Semiconductor, Inc.
13
FRDM-CR20A development board
Figure 10. Push buttons
4.2.4.3
Level translator
The on-board level translator, U2, is used as a level shifter is useful when use with the Arduino system. It
provides the voltage translation from the Arduino 5V system to the Freescale MCU plus transceiver 3.3V
system. The level translator is supplied by the VCC_3V3 source.
Figure 11
shows the translator circuit.
Figure 11. TXB0108 level translators
4.2.4.4
Interface connectors J1, J2, J3 and J4
The four connectors J1, J2, J3 and J4 are 100 mil pin headers mounted on the top (component side)
supporting the FDRM standard connector.
•
Voltage rails VCC_3V3, VCC_5V and V_IN(5-9V) are routed via header J3
— To avoid damage, the exact same voltage should supply peripherals on the FRDM-CR20A that
interface to the Freescale Freedom board supply, except where the level translator (U2) is used.
The pin definitions for the headers are shown in
Table 3
and
Table 4
respectively.
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