This page explains how you can emit output trigger pulses (even complex multitooth patterns) with your GenBoard.

Note that your soundcard is more suitable to generate trigger output (variable amplitude, primary+secondary, etc...). See ElectronicDesign/TriggerSignalGenerator

An ECM normally needs an InputTrigger so it can drive the injectors and ignition drivers. GenBoard has a nice installer-friendly feature to emit output pulses like a simple (even-toothed) or a multitooth trigger wheel would.

This is most useful when doing

Note that output-trigger is just an output signal that can be used for anything. Even just for fun to drive LEDs. However, it is most useful for us when it is used as the inputtrigger of GenBoard (either the same board or another, thus first 2 bullets in above list). This outputtrigger => inputtrigger connection must be done in hardware, eg. with a wire or resistor:

Connect the stim-output signal to the InputTrigger with a resistor (1..10k recommended, but possibly a wire - since a wire is the same as a 0k resistor). See below for VR example.

connection example to emulate a 60-2 tooth VR signal

Useful for the

Read a bit further.

Where is the Stim-output signal?

How do I enable?

The stim(output)trigger '''can be enabled from GenBoard/MenuSystem by msp.. , msq.. and mst.. commands.

This can emit


So mst62msp2a outputs a 36-1 triggerwheel pattern using (0x2a=42 decimal) 42*2048*36 usec crankwheel period (rather low freq. Note that board inputtrigger might not act on too low-freq signal (actual freq-threshold depending on configuration).

What is the overhead during outputtrigger is enabled?

For 2..4 events per virtual-crank rotation overhead is tiny, but with 36-1 or 60-2 events per virtual-crank rotation the overhead is noticable for several thousands RPM.

It can also be used to measure the average latency of event execution. Stimout feature was implemented with Eventqueue in about 20 lines in dispatcher, and 15 lines in menu.c (to allow setting the parameters at runtime), and takes no resources when the feature is switched off (except minor flash-area).

See also