A circuit board that ties together three Arduino Dues.
The Elcano Simulator Bridge printed circuit board (pcb) was designed in 2020. It ties together three Arduino Dues to perform a single task. Documentation is on https://github.com/elcano/Bridge. The board can be used to run three Arduino Dues together, partitioning tasks to different boards. The interconnections are given in Due CARLA_Bridge_Pin_Mappings.xlsx. The three Arduino Dues are labeled
- LL (Low Level) or DBW (Drive by wire)
- HL (High Level) or SH (Sensor Hub)
- Router
Each board takes the CAN RX and TX signals to a 2561 chip that converts them to CAN HI and Lo. The HL is connected to an SD card through SPI (MOSI, MISO, SCK and CS). If jumpers are inserted in JP2, the SPI pins are also connected to the Router. This lets the router control the SD card when the HL does not use it. To let the Router use the SD card, the CS from HL needs to be routed to a digital pin on the router. The schematic shows this as TP15, but the test points on the schematic do not match those on the boards. The CS is pin D35 of the HL, which can be wired to any available pin on the router. Alternatively, any connected path trace between the router and HL can be repurposed.
The board can take external DC power and converts it to the 3.3 V and 5V supplies used by the components. The file BridgeSchematic.png gives a schematic. BOM_V4_CARLA_Bridge.xlsx is the bill of materials for the components on the bridge board.
The two ananlog output signals from the router are controlled by JP1 and JP2. DAC0 from the router goes to LSENSE (A10 on DBW) if pin 2 and 3 of JP1 are connected or to IN2 (A3 on DBW) by connecting pins 1 and 2. DAC1 from the router goes to RSENSE (A11 on DBW) if pin 2 and 3 of JP2 are connected or to IN3 (A2 on DBW) by connecting pins 1 and 2.
In its original function, DBW controlled the throttle, brakes and steering for an autonomous vehicle. SH provided GPS, Magnetometer (digital compass), Sonar readings (C5_Rear and C5_Front), Speedometer (Wheel_Rotation), Optical 2D speedometer (Mouse) and Gyroscope. Additional sensor information would be available over the CAN bus. The Router board connected DBW and SH to a PC running a simulator. The output from DBW went to the simulated vehicle and the simulated state of the vehicle was the input to the sensors on SH. The simulator bridge allowed one to test the hardware and software controlling a vehicle on a simulator.