What?

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

Why?

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.

How?

DB37M to EC36F cable:

30 cm long
Heatshrink cover
Tested

Firmware:

Known good firmware release

Config:

2 injector channels
PWM idle control
Fuel pump output
No ignition channels
12V distributor style trigger
Coolant temperature sensor
Throttle position sensor
Inlet air temp sensor
1 narrow band lambda channel

Pinout

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:

variable resistor (270..470Ohm) between pump+ and nernst
330..470 Ohm 1.5W between heater- and heater+
470..2200 Ohm NTC between nernst and pump- (2x2k2 NTC in parallel is also fine). Make this touch (eg. wrapped together) above heater resistor

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.

DB37	EC36	Function	Comment
1		Ground
2		Ground
3		Ground
19		Sensor Ground/Return
20	2	MAT
21	14	CLT
22	1	TPS
23	-	O2	EC18 Pin 1. See GenBoard/Manual/Config/NBoxygen
24	27	Coil (Tach)	Primary trigger
25		X11 Jumper
26	28	Vref	+5V (to sensors)
27		X12 Jumper
28	25	+12V Power to ECU
29		X13 Jumper
30	3	Fast Idle
31		X14 Jumper
32	7	Injector Drive #1	Injector channel A
33	7	Injector Drive #1	(not really required)
34	19	Injector Drive #2	Injector channel B
35	19	Injector Drive #2	(not really required)
36		N/C
37	15	Fuel Pump

An idea ?

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

Variable frequency output
Variable voltage output
Outputs are controlled via software, not POTs
Ability to read output signals from GenBoard
Various signal/waveform generators

A couple of uses:

System Test. Hook it up and run through the various tests to see that firmware responds in a predictive way.
Hardware Test. Hook it up and take all the soldered hardware for a spin. Perhaps the GenBoard will only short-circuit if certain components are swiched at the same time?
Configuration Test. User has problems with his configuration, load it up and see what happens.
and lots of others.

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

Component suggestions:

http://pdfserv.maxim-ic.com/en/ds/DS1844.pdf digital pot

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..

Trigger outputs
- Primary trigger, representing engine speeds up to 10000 rpm
  - Support for distributor pulse-per-ign signal
  - Support for 24-1, 36-1 and 60-2 wheel signals
- Secondary trigger - synced to primary trigger
  - Support for #1 @ TDC cam trigger
28 digital inputs
- 8x INJFET
- 8x IGN_IGBT
- 4x misc drivers
- Fuel pump
- Fast idle
- 4x stepper outputs (push/pull type)
- 2x misc high current drivers
Analog outputs
- CLT (grounding)
- MAT (grounding)
- TPS (resistive, or maybe 0-5Vout)
- Fuel pressure (Vout or grounding, maybe with jumper to choose)
- Exhaust backpressure (same as for Fuel Pressure)
- Exhaust temperature
- 2 Lambda ouputs. Switchable between 0-1v NB input and WBO2 simulation.
- Knock signal
Digital outputs
- Momentary buttons?
- Toggle switches?
LED's
- 28 LED's for each digital input
- 4 extra, could always be useful
- LED or LCD display for output settings

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.