The trigger hardware is not particularly complex, but there are some options and things that shouldn't be missed
The trigger signals are sensitive. Especially the VR signal at low-RPM.
The following precautions must be applied:
- use shielded cable. The cable must have at least 2 wires besides the shield: the GND and the signal itself (VR- and VR+)
- The shielding must be connected on the ECU side only, so the shielding is NOT actually used for the GND signal
- use GND and not GND5. The GND5 signal would make the signal noisy (when FETs and IGBTs switch).
- connect sensor GND only near the EC36 connector (not at battery and not at other places). Search the web for "ground loop" if you want to understand in more depth.
Primary trigger (trigg1)
For Hall setup:
- R30=10k (pullup resistor)
- C88 = does not matter
- short SJ1
- R55=10k
- short SJ2
- do NOT short SJ6
- The other parts near the LM1815 do not matter
Adaptive hysteresis: for use with VR sensor (LM1815 involved)
- R30= NOT soldered (unsolder it if there)
- C88 = does not matter
- R55=10K
- short SJ1
- do NOT short SJ2
- short SJ6
- D14 is optional (3.9..5.1V zener diode)
- U11 (LM8515)
- R56 (10K) resistor of input RC lowpass
- C30 capacitor of input RC lowpass (1..3.3nF for multitooth, upto 100nF for coiltype-only-for-sure setup)
- R57 (75K)
- R87 (1 .. 1.6M) resistor of peak-detector
- C38 (0.22uF) capacitor of peak-detector
- R88 (10K) output pullup resistor
- C31 (1nF)
- C39 (0.22uF)
- measure with DVM 200kOhm range between primary trigger (trigger1_conn) signal and LM1815 pin3. If >21kOhm than you don't have VR input selected. Check around SJ1
- follow the path on the GenBoard/VerThree/Schematic, from the inputtrigger to the LM1815 input pin: Identify the components that are in the path
- measure with DVM 2kOhm range between LM1815 pin12 to AVR's pin29 (IC1). If > 10 Ohm, than SJ6 is not shorted
- apply self stim, it only requires a 1..10uF capacitor and a few simple menu-commands (see OutputTrigger) and it can save you hours. Don't skip this unless the trigger setup works immediately.
setting up VR on v3.2 - most parts are soldered. Still check at least the SJ6 and R30.
The reason for the 2 missing bits: other option would be HALL type: therefore this is only done before shipping when the user declares (eg. on project wiki page, or order note, preferrably both) that he needs VR type.
- short SJ6 (right below LM1815) by soldering a very short wire
- connect primary trigger input to the internal signal directly (no capacitor needed, just a very short wire). Either
- put a jumper: connect the upper-middle pin to the upper-right pin of 3x2 pinheader (viewing from the "Top" side)
- or rather solder on bottom of the board to short JP2 and JP7 : connect upper-middle to upper-left pin (viewing from the "Bottom" side)
The 3x2 pinheader is between the EC36 and the LM1815.
Make sure you view the board in a good orientation, so econoseal points down and "Top" or "Bottom" text is readable.
setting up HALL on v3.2
trigger #1:
- connect JP2 & JP7 (jumper top right of the 2x3)
- short SJ2 (solder blob)
trigger #2:
- connect JP5 & JP13 (jumper bottom right of the 2x3)
- short SJ5 (solder blob)
[Picture of 2x3 header, SJ6, SJ2 on Genboard v3.2]
![[Picture of 2x3 header, SJ6, SJ2 on Genboard v3.2]](http://www.vems.hu/files/genboardv3/images/v3.2/v3.2_trigger_top.jpg){kind=link}
Special setup: when input does not go below 0V
You only need a C88=10uF (1210, 35V) when the signal otherwise does not go below zero. SJ1 must not be shorted in this case.
Useful, for example when stealing the 0.65V based VR signal of an alien ECM (as on MembersPage/Gabor).
Note that R30 pullup resistor is not recommended for VR sensor. If you already have an R30 pullup, that produces an offset (as a voltage divider with the VR sensor's internal resistance) and make the input NOT go below 0V at low RPM (cranking): fix it by removing R30 or following this section ( apply C88=10uF and not short SJ1).
Secondary trigger (Trigg2):
- For Hall setup: R91 10k, SJ5, (SJ10 or C89)
- For use with LM1815: U12, R58, R59, R89, R90, R91, C32, C33, C34, C40, D24, D27, SJ7 & SJ10 (shorted)
See also
- GenBoard/Manual
- GenBoard/VerThree/Schematic
- [very good introduction] to VR and HALL sensors