See BroadcastDatastreamAim for generic information on AIM-stream, and configuration of VEMS ECU => 1st serial
- if setting up an unknown non-VEMS receiver, set up 1st serial to send AIM data as a test first; include results of those tests in any report if you have any problem
- Note that v3 wheelspeed has a configurable *10 multipler to be compatible also with some non-compliant receiver devices.
Configure 2nd UART to send "5 byte stream" with datacontent matching the AIM (but currently no wasted gaps)
Requirements
- >= 1.2.35 firmware (compile time after 2016-07-14)
Configuration (VemsTune checklist)
- VT -> Ecu Calibration:
- iButton anti theft: disabled
- prohibit/iButton2 high byte: 8
- prohibit/iButton2 low byte: 1
- VT ->Ecu Logger -> Ecu Log Settings:
- GPS Log Baud rate: 19200 (actually 2nd serial port baudrate; in old VT if this entry is greyed out => temporarily enable bytestuffing)
- Ecu log use byte stuffed format: disabled
- Automatic GPS Log to SD card on main serial port : disabled
- SD Card Trigger Log: disabled
- VT->Outputs->Display Settings:
- AIM disable => send via 2nd serial if 2nd serial is free (renamed accordingly in VT 2016-07-..)
- AIM enabled => send via 1st serial (as traditionally), respecting the "teletype restriction" (even those receivers should pick it up that do not understand the bytesequence without the wasted gaps)
- but only when VT -> Ecu Calibration:
- prohibit/iButton2 high byte: NOT 8 ; make sure this value is NOT 8 (eg. 255 is fine) before enabling AIM
2nd COM wiring
2nd COM port for live data (FW 1.2.35 and newer), 2nd RS232 3 pin (unpopulated header) towards the main processor:
- GND (easy to locate)
- TX (measures appr -7V when idle)
- RX (input, as an experiment pull to +5V with 1k resistor and it will follow to 3..4V perhaps).
Located above the MAX232D (SOIC16) chip, different header, otherwise the same pinout as the 1st RS232 (which is towards the L293D stepper driver IC). See GenBoard/VerThree/Schematic
Useful for:
- AimToCanBusPinout => most often for CAN dash
- [Android VEMS-display]
- can be connected via [BT-RS232] bluetooth (most common)
- or wired: serial port (RS232 or TTL serial port, or USB-adapter, if available and configured in Android).
- [VEMS round] (displayonly or full featured round).
- [Vt(VemsTune) can receive AIM data on a secondary serial cable from the ECU]
- since VT is capable of superior data connection to VEMS ECU (with much greater baudrate, speeds and especially data content), this is mostly used for testing AIM stream or data-compatibility, or perhaps just "tapping/sniffing" when already broadcasting some AIM-stream to one or multiple AIM receiver devices that VEMS ECU sends out (even VEMS ECU RX is not used, so absolutely HARD-safe against any accidental or adverse tamper, may that be a concern).
- NOTE that the AIM stream can be sent to one or multiple devices...
- 1 TX can be connected to upto 8 RX (yes, 8 devices), depending on baud rate (19200,8n1 is common for AIM stream), cabling, receiver load and transmitter strength
- GND (of all devices) must be connected properly: strong, and (no "ground loops").