Versatile Engine Management Systems - VEMS wiki

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 ( <300RPM, thus cranking). VR is not really sensitive from noise via capacitive coupling (although long wires that drive ignition coils arranged parallel might inject noise) but rather to noise injected through ground loop (switched power-currents that partially sneak through GND instead of GND5) if not installed properly.

• If GND5 is not connected, you get smoke from the ECM.
• If only 1..2 GND5 wire connected instead of 4..5 you get more ground-noise.
• If GND-GND5 bridge (a soldered "arch" left to the 4 FETdrivers, 30mm under VEMS logo on top side) is still soldered (and not cut), you get the ground-loop that injects noise into VR and might make startup problematic

The following precautions highly recommended:

• 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 connecting the GND signal to both ends
• use GND (for VR-) 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.

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v3.6

Some nice pics on MembersPage/Larsa/VEMSpictures

Primary trigger is same as v3.3 - see v3.3 primary trigger=...

• for secondary trigger HALL (or sectrig unused), a small blob short is needed between the SOT23 NPN base to collector (transistor not populated, just a small short to route the signal) as shown with red on the image
  • Verify this: that HALL-input pullup towards +5V is appr 2k7..4k7. The signal should be min 3.3V when input is open. If you pull down the signal with a 1kOhm resistance, than measured DC voltage should be minimum 870 mV (voltage divider equation: U=5V * R/(R + Rpullup))

• if you had sectrig=VR or sectrig=auditrigger (and converting to secrig=HALL), than also
  • open SJ7 solder-blob on the bottom, so LM1815pin12 output is DISconnected from the microcontroller input pin. This blob is on the bottom, close, to the line of FETs.
  • actually this is the only step required if converting from sectrig=auditrigger (because that already has the HALL part of the circuit set up from EC36/13)

Secondary trigger setup is also similar to v3.3 but more versatile, allowing

• for secondary trigger=auditrigger (combined setup of crankhome VR and camHALL masking, possibly with onboard cam-HALL inverter)
  • there is onboard provision for AudiTrigger/CamHALLInverter. A SOT23 NPN (like BC817 but almost any NPN transistor would work) in place of the red mark on the pic above, and a 2k7 pullup resistor (a bit to the right)
  • The second LM1815 and the related blob at the PCB bottom under the FETs is needed. (same as with v3.3 sectrig VR setup)

• for secondary trigger=VR (when not using the 3-sensor auditrigger), we recommend that EC36/13 is used as sectrig VR input. This way EC18/12 can be used for analog input (0-5V, sensitive mcp3208 input).
  • The second LM1815 and the related blob at the bottom side under the FETs is needed.
• wether you order assembled or assemble yourself, read the recommended econoseal pins at [webshop page]

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v3.1 (trigg1) primary trigger=HALL

For Hall setup:

• R30=2k7 (pullup resistor. 10k is a bit too high)
• C88 = does not matter
• short SJ1
• R55=10k
• do NOT short SJ2
  • remove R56(=10k, next to SJ2)
  • and solder SJ2=150k (or at min 47k resistor; this makes RC filter with the IC1 line's appr. 10..20pF - which comes from AVR input capacitance + trace capacitance)
• do NOT short SJ6
• The other parts near the LM1815 do not matter

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v3.1 (trigg1) primary trigger=VR

• R30 pullup resistor NOT soldered (unsolder it if there). A few mm left from the 2x3 trigger pinheader. R30 is the horizontal, 0805 package; further away from the EC36
• 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.

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v3.2 / v3.3 (trig1) primary trigger=VR - most parts are soldered. Still check at least the SJ6 and R30.

THIS IS THE MOST COMMON SETUP - therefore it is described with picture on the trigger main page: GenBoard/Manual/InputTrigger

• on v3.2, check that R30 pullup resistor NOT soldered (unsolder it if there). A few mm left from the 2x3 trigger pinheader. R30 is the horizontal, 0805 package; further away from the EC36. On v3.3 this is not soldered in factory
• 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, but

• on v3.2 it has an additional GND pad besides the 3x2 pins.
• on v3.3 it lacks a pin (so only 5 pin instead of 6) because trig2 is connected with PCB trace

Make sure you view the board in a good orientation, so econoseal points down and "Top" or "Bottom" text is readable.

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v3.2 (trig1) primary trigger=HALL

• solder JP2 & JP7: this is the top right of the 2x3 header; red on the [image]
• short SJ2
• do NOT short SJ6 (remove the blob if there)
• R30=2k7 pullup resistor (2k .. 4.7k). Note that 10k is a bit too high
• remove R56(=10k, next to SJ2). This is not strictly necessary if R30 is 4k7 or lower.
• measure DC voltage between SJ2 and GND (with board powered, but HALL sensor not connected or inactive): must be higher than 3V

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v3.3 (trig1) primary trigger=HALL

• solder JP2 & JP7: this is the top right of the 2x3 header; red on the [image]. The same area of v3.3 looks slightly different (no bottom-right pad, where the blue jumper sits on the image), but never mind. The primary trigger is the same, the changes are at the secondary trigger, eg. 1 throughole pin dropped, and R48 moved to bottom.
• short SJ2
• do NOT short SJ6 (remove the blob if there)
• R30=2k7 pullup resistor (2k .. 4.7k). Note that 10k is a bit too high
• remove R56(=18k, next to SJ2). This is not necessary if R30 is 4k7 or lower.
• measure DC voltage between SJ2 and GND (with board powered, but HALL sensor not connected or inactive): must be higher than 3V

[ Converting from VR to HALL (Swedish)]

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v3.2 (trig2) secondary trigger=HALL

[Picture of 2x3 header, SJ6, SJ2 on Genboard v3.2] R56 and C30 are right after SJ2 (LM1815 pin3).

• connect JP5 & JP13 (jumper bottom right of the 2x3) as on the above pic
• R91=10k
• short SJ10 (or short C89)

SJ5

There are 2 schools, one says to short SJ5 (this should work well, with no difference for a good signal). The other likes a bit extra filtering and says:

NOT short SJ5

• recommended SJ5=150k (resistor; this makes RC filter with the IC3 line's appr. 10..20pF - which comes from AVR input capacitance + trace capacitance)

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v3.2 Primary and Secondary setup for Hall - similar instructions as above

• Bottom view [Picture of trigger area]
• Top view 1 [Picture near jumpers]

Notes - apply both for primary an secondary trigger

• The jumpers are in place for the trigger signals, should be soldered on the bottom of the board for better vibration resistance.
• added 1n capacitors between ground and each trigger signal. Actually on the pads of D14 and D17 (originally ment for 5V1 zener diodes), but other places can be OK as well.

Primary trigger related:

• Top view 2 [Picture near LM1815 chip]
• R30=1k strong pullup resistor
• shorted SJ2
• removed R56 (103=10k), the resistor next to SJ2

Secondary trigger related:

• R48=1k strong pullup resistor
• shorted SJ5 (on the bottom)

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v3.0 .. v3.1 secondary trigger (Trigg2) VR setup (with LM1815)

U12, R58, R59, R89, R90, R91, C32, C33, C34, C40, D24, D27, SJ7 & SJ10 (shorted)

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v3.2 secondary trigger (Trigg2) VR setup (with LM1815)

Solder

• LM1815
• SJ7

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v3.3 secondary trigger=VR hardware setup (often called AudiTrigger, but the same applies for traditional secondary_trigger=VR)

• remove C103 or replace with 1nF
  • only necessary if the secondary_trigger HALL signal is actually used (not just the VR). For new installs, best to do it in any case, so this is the standard. Assembled controllers sent out after 2005.12.31 have C103 replaced. If you assembled yourself, or actually use HALL secondary trigger with an assembled controller sent out in 2005, see GenBoard/Manual/InputTriggerHardWare/ReplaceC103
• don't forget to set up primary trigger (usually for VR, see above)
• Check [assembled controller item] to understand it better
• solder the 2nd LM1815 (same orientation as first: pin1 closest to atmega)
• R182=0k resistor/short at LM1815pin7. This is very important for the adaptive hysteresis to work. Has the same function as R181 >= 100k for the first LM1815 (soldered in factory) but 0k (short) is more appropriate here.
  • optionally increasing the neighboring 220nF capacitor by adding an additional (solder piggyback) +1uF or +2.2uF might be a good idea
• wire from EC18pin12 to the 2nd LM1815 input pad (that goes through a 18k resistor to pin3 of the second LM1815)
• SJ7 solder-blob on the bottom, so LM1815pin12 output is connected to the microcontroller input pin. This blob is on the bottom, close, to the line of FETs.

Warning:

EC36pin13 is set up for HALL (nothing to do), but beware, that this setup (with the SJ7 blob shorted) does NOT work for secondary_trigger=HALL only:

• OK: EC18pin12=VR, EC36pin13=HALL (for audi's 3-signal system)

• OK: EC18pin12=VR (EC36pin13 not connected) not for audi, but for a 1-tooth VR-type cam signal (like in Fiat Stilo)

• BEWARE: EC18pin12=not connected, EC36pin13=HALL setup will only work if you remove the SJ7 solder-blob from the bottom (or remove the LM1815, but that's harder :-)

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v3.3 Secondary trigger (Trigg2) Hall setup:

• remove C103 or replace with 1nF
  • only necessary if the secondary trigger HALL signal is actually used, but for new installs, best to do it in any case, so this is the standard. Assembled controllers sent out after 2005.12.31 have C103 replaced. If you assembled yourself, or actually use HALL secondary trigger with an assembled controller sent out in 2005, see GenBoard/Manual/InputTriggerHardWare/ReplaceC103

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Special setup: VR, when input does not go below 0V - very rare!!!

You only need a series capacitance (eg. 10uF, 1210 package, 25V or 35V) when the signal otherwise does not go below 0 Volt. The capacitor allows a voltage difference, but still forward the signal.

Useful, for example when stealing the 0.65V based VR signal of an alien ECM (as on MembersPage/Gabor). SJ1 must not be shorted in this case.

• for v3.0 and v3.1: C88=10uF
• v3.2 and v3.3: 10uF, 25V (or bigger) cap must be soldered instead of the input jumper (that is between JP2 and JP7)

The rest of the VR setup is as usual, see in the relevant section (make sure R30 pullup resistor is not soldered!)

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See also

• GenBoard/Manual
• GenBoard/VerThree/Schematic
• [very good introduction] to VR and HALL sensors

Document last modified 2010-07-14 09:52:15

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