Figure 8 display the highlighted 9 pin connector J304 on bottom side of SoM_IoT_1V2 printed circuit board. This connector allocate the large-scale integrated circuit R-IN32M3-EC with external SPI and additional SYNC signals. Furthermore the power supply pins VCC33 and GROUND are connected on J202.
Pin 1 (VCC33) and pin 2 (GND) should be connect with external DC voltage source. The SoM_iRJ45 is specified for an input voltage range of 3,0V DC to 3,6V DC.
Note: Higher voltage (above 3.6V DC) at power supply pins may cause damage this module!
Pin 3 
Pin 19 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 420 connect the RESETZ ball of R-IN32M3-EC. So an external reset signal can initialize the CPU core and the internal peripheral modules.
Pin 521 complies the MISO function for SPI connection. This pin connect the R-IN32M3-EC CSIH serial data output signal at Port P47 (CSISO0).
Pin 622 complies the MOSI function for SPI connection. This pin connect the R-IN32M3-EC CSIH serial data input signal at Port P46 (CSISI0).
Pin 723 complies the SCK function for SPI connection. This channel 0 CSIH signal connect the serial clock of R-IN32M3-EC at Port P45.
Pin 824 (CATSYNC0) connect Port P11 of R-IN32M3-EC and is able to use as GPIO or EtherCAT Sync0 signal connection.Pin 9
Pin 25 (CATSYNC1) connect Port P10 of R-IN32M3-EC and is able to use as GPIO or EtherCAT Sync1 signal connection.
Pin 26 (CATSYNC1) connect Port P10 of R-IN32M3-EC and is able to use as GPIO or EtherCAT Sync1 signal connection.
Pin 27 (CATSYNC1) connect Port P10 of R-IN32M3-EC and is able to use as GPIO or EtherCAT Sync1 signal connection.