Figure 10 display the highlighted 9 pin connector J301 on bottom side of SoM_IoT_1V2 2V0 printed circuit board. This connector allocate the large-scale integrated circuit With connector J301 are two 10BASE-T, 100BASE-TX/FX ethernet ports realized. The SoM-iRJ45 module includes the 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 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.
Pin 5 complies the MISO function for SPI connection. This pin connect the R-IN32M3-EC CSIH serial data output signal at Port P47 (CSISO0).
Pin 6 complies the MOSI function for SPI connection. This pin connect the R-IN32M3-EC CSIH serial data input signal at Port P46 (CSISI0).
Pin 7 complies the SCK function for SPI connection. This channel 0 CSIH signal connect the serial clock of R-IN32M3-EC at Port P45.
Pin 8 (CATSYNC0) connect Port P11 of R-IN32M3-EC and is able to use as GPIO or EtherCAT Sync0 signal connection.
Pin 9 (CATSYNC1) connect Port P10 of R-IN32M3-EC and is able to use as GPIO or EtherCAT Sync1 signal connection.Ethernet Switch with additional TVS array connection for ESD and transient protection. Furthermore, the magnetic components for galvanic decoupling and signal integrity are offered too. See description below on this page.
Pin 37 (RX0_N) connect the differential receiver_N signal of ethernet port 0 and transfer this signal to target device.
Pin 38 (RX0_P) connect the differential receiver_P signal of ethernet port 0 and transfer this signal to target device.
Pin 39 (TX0_N) connect the differential transceiver_N signal of ethernet port 0 and transfer this signal to target device.
Pin 40 (TX0_P) connect the differential transceiver_P signal of ethernet port 0 and transfer this signal to target device.
Pin 41 (SHIELD) connect the external Ethernet-Shield for both ethernet ports.
Pin 42 (RX1_N) connect the differential receiver_N signal of ethernet port 1 and transfer this signal to target device.
Pin 43 (RX1_P) connect the differential receiver_P signal of ethernet port 1 and transfer this signal to target device.
Pin 44 (TX1_N) connect the differential transceiver_N signal of ethernet port 1 and transfer this signal to target device.
Pin 45 (TX1_P) connect the differential transceiver_P signal of ethernet port 1 and transfer this signal to target device.
Exemplary magnetic topology
Following Schematic 4 show the wiring concept of ethernet port 0 between MCU (R-IN32M3-EC) and Ethernet jack connection contacts. A consistent differential signal cabling is recommended. For deeper information about used HX1188 magnetic circuit topology see the J301 SoM_IoT_1V2 description.
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All components on left side of blue marked J301 connector are equipped on SoM_iRJ45 module. The schematically pictured RJ45 connector has to be placed on target device and is not part of SoM module.
Note: It is recommended the open pins of the external Ethernet connectors on carrier board, for RJ45 Jacks the pin 4/5 and 7/8, to decouple with 75Ω resistors and 1MΩ resistor to shield potential.
Ethernet Shield Connection
The Ethernet shielding connection for the external cabling shield has to be connected at J301 pin 41. Which is pictured in Schematic 3. This potential (J301_Pin41) is recommended to connect with functional earth in the local operating environment. This ensures an interference deflection and protect the module method of operating.
Note: Do not connect J301 pin 41 with GND, otherwise all cable interspersed disturbances will have negative influence to module circuit. This SHIELD is internal decoupled with resistor/capacitor network to system GND!