STMicroelectronics AEK-COM-10BASET Evaluation Board

The 10BASE-T1S automotive Ethernet enhances in-vehicle network (IVN) architectures by connecting sensors, car bodies, and infotainment engine control units (ECUs). This protocol supports half-duplex and full-duplex communication, allowing a point-to-point direct connection between two nodes or a multidrop topology with up to eight nodes connected on a single 25m bus segment. The 10BASE-T1S reduces total system cost using a single pair of wires and a multidrop bus architecture. The 10BASE-T1S also increases system scalability since several nodes can operate on the same bus line with high data throughput. Thanks to the multidrop topology, multiple applications can be implemented on a single cable in zonal architectures, for example, in the door zone, the window lifter, mirror control, speakers, lock, ultrasonic, ambient light, and indicator light.

The STMicroelectronics AEK-COM-10BASET acts as a gateway to interconnect incompatible communication systems, allowing a vehicle zone sensor/actuator to receive messages in the 10BASE-T1S protocol format even if the zone components are not able to communicate via Ethernet. The board features a PHY-MAC transceiver, which communicates with the MCU via SPI, and a PHY-only transceiver requiring an Ethernet MAC to run in the MCU. The transceivers support only half-duplex communication. Both are connected to the MCU, one using the MII port while the other uses an SPI channel. The embedded firmware manages a software-implemented Ethernet MAC and runs under the FreeRTOS™ operating system.

The AEK-COM-10BASET is very flexible, allowing several gateway packet conversions to and from 10BASE-T1S, CAN-FD, and SPI. The function can be limited to gateway purposes or extended to decode actuation commands and forward them to several daughter boards via the available ports. For example, a Power Distribution Unit (PDU) daughter board containing E-fuses can be controlled via CAN or SPI by decoding the 10BASE-T1S frames. The AEK-COM-10BASET hosts an OpenOCD debugger/programmer, MCU peripheral connectors, wake-up, reset buttons, and a reverse battery protection circuit for higher safety.

The board features a preloaded demo example that involves a loopback test among the two 10BASET1S channels and two CAN channels. The message is sent via CAN sender port, packed in 10BASET1S, sent to the other 10BASET1S channel, and finally unpacked for a CAN receiving port. A stable linear voltage regulator (LDO) embedded in the L5963 IC provides the MCU ADC reference voltage.