Figure 9 display the highlighted 9 pin connector J303 on bottom side of SoM_IoT_2V0 printed circuit board. This connector allocate the large-scale integrated circuit R-IN32M3-EC with external I2C and two additional UART signals.
Pin 28 (I2C_SDA1) This pin is used for serial data input and output. This pin is an N-ch open-drain output for both master and slave devices on real time port RP01 of R-IN32M3-EC realized. For Functional Overview see also User’s Manual R18UZ0007EJ1100 chapter 18 I2C BUS (IICB)
Note: Because the outputs of the serial clock line and serial data bus line are N-ch open-drain outputs, an external pull-up resistor must be connected to these lines
Pin 29 (I2C_SCL1) This pin is used for serial clock input and output. This pin is an N-ch open-drain output for both master and slave devices on real time port RP00 of R-IN32M3-EC realized.
Pin 30 (UART_RXD0) Receive data input on port P20 of R-IN32M3-EC (URTJ0TRXD). For Interrupts and peripheral modules see also User’s Manual R18UZ0007EJ1100 chapter 16 Asynchronous Serial Interface J (UARTJ)
Pin 31 (UART_TXD0) Transmit data output on port P21 of R-IN32M3-EC (URTJ0TTXD).
Pin 32 (UART_RTS0) P43
Pin 33 (GND) optional Ground
Pin 34 (UART_RXD1) Receive data input on port P30 of R-IN32M3-EC (URTJ1TRXD).
Pin 35 (UART_TXD1) Transmit data output on port P31 of R-IN32M3-EC (URTJ1TTXD).
Pin 36 (UART_RTS1) P74