Rather an example of how NOT to do it.
We received a home-assembled ECU with a BT-serial (not RS232 but logiclevel serial "fbus") module inside ECU: an unsupported setup (connected wrong so it did not work and prevented VT communications; Disconnecting BT-RS232 => VT communication started to work immediately).
- Bluetooth inside a metal case will not work. (see "Faraday cage")
- First serial port: when VT is connected PC TX => ECU RX cannot be driven by the BT module at the same time, so BT module must be disconnected (this happens when DSUB9 connector is disconnected)
- but the module was connected inside the case to the ISP header, preventing the ST232 chip to drive main processor RX properly (preventing VT communications)
See BroadcastDatastreamAim for AIM only (not triggerframe), this way ECU => BT module one-way communication should work.
Second RS232 is preferred
- 2nd serial can also send AIM stream if configured so, and no VT problem. See BroadcastDatastreamAimSecondSerial
Possible Solutions:
- Should we provide a BT-RS232 module so that it can transmit from outside the metal case ? We also make a 2nd RS232 DSUB9/pin9=5V
- or... Should we connect 2nd serial TX => BT Module (inside the ECU) for AIM comm ?
- might work with ECU endplate removed