[Ovmsdev] Presentation and first questions

[Mark Webb-Johnson]

Romuald,

Welcome. To answer your questions:

Goals seem fine. OVMS has three CAN buses, expansion board area, and can (sic) write to the third CAN bus. Be aware that there are only two free full GPIOs available, but as I2C only uses two (SDA, SCL), you should hopefully be ok.

No traps that I am aware of. Just follow the developer’s guide very carefully (in particularly regarding ESP IDF and compiler versions) to get your build environment up and running, and start with the default sdkconfig copied from support/sdkconfig.default.hw31.

OpenEnergyMonitor should have some prototyping boards (I don’t think they list them on the website, but you can ask to confirm). If not, I can supply from Hong Kong but shipping times and costs are still crazy at the moment.

Have a look at components/can for the framework. You just need a pointer to the can bus object, and then call the Write() method on it. You can look at can/src/can.c can_tx() function for an example. To do it periodically, you would need a task, or if lightweight use the timer functions. If you only need to write slowly (once a second or so), then even a script could do it.

Regards, Mark.

> On 27 Apr 2023, at 9:06 PM, Romuald Conty (Opus Codium) <romuald at opus-codium.fr> wrote:
> 
> Signed PGP part
> Hi,
> 
> I'm Romuald, a FLOSS enthusiast, and I'm working on a project where I'm going
> to use OVMS platform as a part of the vehicle hybridisation system.
> 
> To reach my goals, I'll have to:
> - Read two CAN buses to grab and display values on a HUD
> - Make an expansion board with some IC which requires to talk using I²C
> - Publish events on a third CAN bus which exposes additional sensors values
> 
> I have a lot of questions about the really exiting OVMS board and platform, to
> start here are my firsts:
> - Is there is any trap I should take care that is not described in users or
> developers documentation regarding my goals?
> - Is there is any place where I can find some prototype boards¹?
> - Could someone guide me to be able to periodically wrote values on CAN bus
> using the OVMS code architecture²?
> 
> Thanks for this awesome project!
> 
> [1] I bough my OVMS from OpenEnergyMonitor and unfortunately none are sold
> [2] It's about read some sensors, compute values and provide results at a
> traditional CAN frequency on the bus.
> 
> --
> Romuald Conty
> Opus Codium
> 
> 

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