Loopbacking the controller's RS232 (serial port)
In special, rare cases, eg. when firmware upload is interrupted or unable to communicate with firmware for some other reason, use RS232 loopback to force ECU stay in bootloader mode after bootup:
- power down the controller (GenBoard ECU or round)
- remove fuelpump, injector and ignition fuses (or relay), and remove injector connectors.
- disconnect any device (usually PC) from the controller (GenBoard or round)
- connect the ECU RS232 (serial port) DSUB9 pin2 to pin3, with a wire, a conducting paperclip, or a dedicated loopback connector
- power up GenBoard
- remove the loopback
- connect PC to GenBoard RS232 (serial port)
- as a test, you can try to talk to GenBoard bootloader via TerminalProgram in 19200,8n1 say S (uppercase!),p,v and get AVREFI1, 20, 20 or alike.
- normally not needed, but do it if you have problem with the steps.
- Disconnect from TerminalProgram (or exit) to free up the serial port.
- run the PC side firmware upload application
- VemsTune bootloader mode detected => Stay ; Tools / Firmware / Firmware upload (VT might recommend the multifunction "upgrade wizard", but the old upload is best in this case: saving old vemscfg would likely not succeed anyway if you're doing this)
- OBSOLETE: or edit upload_firmware.bat to set COM port. (This runs megaloader. Found in MegaTune distribution)
- you might need to reboot (turn +12V supply OFF and ON)
- get (or prepare) the new configuration that matches your setup (firmware, wiring and other)
- IMPORTANT: if you are upgrading from a working different firmware, read GenBoard/UnderDevelopment/FirmwareChanges and update configuration to match the new firmware.
- upload configuration and tables
Loopbacking the PC RS232 (serial port) - to test the PC RS232 port
- important: disconnect any active device (usually a controller) from the PC
- connect the PC RS232 (serial output) DSUB9 pin2 to pin3, with a wire, a conducting paperclip, or a dedicated loopback connector
- start a TerminalProgram (such as bray terminal or hyperterm). Type TESTTEXT. If the terminal keeps echoing what you type (TESTTEXT in this case), than the selected serial port (often USB-RS232 adapter or bluetooth-RS232 adapter and the installed driver) works.
- note that this works in any baudrate setting (9600 / 19200 / other...)
- BEWARE THAT PLUGGING THE USB-RS232 adapter in another USB slot usually results in changed comm-port. Eg. changes from COM5 to COM4