A plug'n'play adaptor to let Dave desk-test the MegaTunix code for VEMS.


Dave A needs a working Genboard to test with. This means he needs a way to fake signals and check the values. He has a MS Stimulator, so an adaptor to Genboard is a quick and an easy way to provide this.


DB37M to EC36F cable:




Pins 1 to 19 on the first row of the DB37 connector on the MegaSquirt board are grounds (not important here but pin 19 is supposed to be a special sensor ground but no distinction is made on the v2.2 PCB). On the Stimulator board pins 7 to 11 are used as grounds so these are the ones to tie together with grounds on the Genboard: Power ground pins 5, 21, 32 and "regular ground" pin 26.

Oxygen sensor input

could be connected to one of the analog inputs of the MCP3208 (?). Possible, but non-standard... It's unfortunate that we're using EC18 as well, but std config appears to be through Nernst Channel 2 / EC18-1.

I think it makes more sense to prepare for testing WBO2 channel, since NBO2 is very rare nowadays. (also: WBO2 testing equipment helps to find out if the same channel works for NBO2).

Proposal for (sensorless test-) setup:

If you get the parameters right, this setup can make a stable (wb)o2 signal on LCD and MegaTunix. The necessary condition is that both Ri (AC level on nernst) and nernstdc (appr 4.45V DC on nernst) can be kept on target by the controller.

1 Ground 
2 Ground 
3 Ground 
19 Sensor Ground/Return 
23-O2EC18 Pin 1. See GenBoard/Manual/Config/NBoxygen
2427Coil (Tach)Primary trigger
25 X11 Jumper 
2628Vref+5V (to sensors)
27 X12 Jumper 
2825+12V Power to ECU 
29 X13 Jumper 
303Fast Idle 
31 X14 Jumper 
327Injector Drive #1Injector channel A
337Injector Drive #1(not really required)
3419 Injector Drive #2Injector channel B
3519Injector Drive #2(not really required)
36 N/C 
3715Fuel Pump 

An idea ?

Would it be possible (within a certain time and money frame) to create a GenboardStimulator with the following features:

A couple of uses:

I guess it's not impossible to create; but how much would it cost? Money and time-wise?

Component suggestions:

Spec for the planned smart-stim

Even though work on this is started, i won't drop the idea of a mot-ms stimulator adapter harness..

WBO2 can be tested as documented at top of page by mcell.

The minimalistic VemsFrontier/MiracleBoard would provide more than the stims that are used today - definitely not several dozen inputs and outputs (if that's needed, use a v3 :-)

Today, most people just use ElectronicDesign/TriggerSignalGenerator or OutputTrigger to test board. Very simple and effective.