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Pin 3 has chip select (CS) function for R-IN32M3-EC Clocked Serial Interface H (CSIH) which works in Slave Mode at CSIH channel 0. The used chip select sink for this R-IN32M3-EC based module is Port P70, Port P71 drives permanently to GND level.
Pin 4 connect the RESETZ ball of R-IN32M3-EC. So an external reset signal can initialize the CPU core and the internal peripheral modules.
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