Innovate Motorsports OT-2 SDK - Manual (Page 38)

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Special Considerations Entering Expert Modes
Before entering an Expert Mode, the OT-1b/2 firmware cleanly suspends the thread that
normally does OBD-II polling, this includes making sure that all OBD-II hardware lines
are in a reasonable state. If the unit is already connected to an ECU, this process is
reasonably quick. However, if the unit is set to automatic, and no ECU connection has yet
been established, it can take a long time. The response to the ‘e’ command may not come
for 10 seconds or more (don’t worry, it does not count against your watchdog time).
For some applications, this may be acceptable. However, in many it can make for an
unacceptable user experience.
Depending on your exact requirements, you could consider one of the following
workarounds. First, you might consider not entering an expert mode until a connection to
an ECU has been established. You could then use the result from Get Connection Status
(‘j’) to decide which mode to use.
This can be a nice approach, but it will not work if either:
a. The ECU uses a protocol we do not understand (but you do)
b. Our code is not compatible with the ECU
And yes, obviously, b. cases do exist. In fact, that is one of the cases that expert mode can
be particularly useful. In these cases, you might consider a different approach and
configure the unit for something other than automatic. Ideally you would set it to a
protocol that is fast (CAN or J1850pwm), but which you know is not supported. In this
case entry into expert mode will be reasonably quick, and the normal OBD-II foreground
loop will not have mucked up the water, so to speak, with a lot of intermittent
connectivity to the ECU.
But, regardless of rather you get into an expert mode by waiting, or a workaround, you
still have to use it, so…