markusdd/OpenDTUFusionDocs

Pin mapping for OpenDTU-onBattery

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swingstate commented

Hi Markus,

two pre-sales question -

I have read the docs and understand that some of the GPIOs (9 - 14) can be mapped to anything else. I would like to map the VE.Direct feature of OpenDTU-onBattery to e.g. GPIO 9 and 10 from the SPI header. Would that work?

Are the IPEX connectors standard size so other pigtails for SMA antennas can be connected?

markusdd commented

yes. They are normal IPEX connectors. (as indicated in the docs, not the 'mini' ones you find on some newer laptop wifi cards).

As for re-using GPIOs: they are the normal 3.3V GPIOs of the ESP32-S3 then. I do not know enough about Victron if 3.3V is the correct voltage for VE.Direct, that would need to be asked at OpenDTO onBattery.

We do nothing on the board with these lines except routing them to the pin-header straight form the ESP32-S3 module. So there are no pulls/level shifters etc.

philippsandhaus commented

Regarding VE.Direct: There are some Victron devices like the MPPT Solar chargers which use 5V and some use 3.3 V like the SmartShunt. I also plan to use the headers on the Fusion Board for this, but I plan to solder a header socket on a ADUM1201 level shifter with a VE. Direct cable or socket on the other side and place it directly on the 4header group with the SDA/SCL Pins of the board. If this works it should a nice and clean solution.

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swingstate commented

Thanks Markus,

The VE.Direct implementation for OpenDTU makes use of the GND, TX, RX Pins. The VCC PIN remains unused. Hence my understanding is that voltages are not a topic for this interface. However, does any of the available PINs on the fusion board provide GND?

markusdd commented

That is incorrect. Of course the high and low levels of the signals matter. If you drive a 5V signal into an ESP32 you will destroy it. So anything you connect to an ESP board (not just the fusion) must not exceed that 3.3V voltage on the signal pins.
GND is not an issue, it is marked on the board and available at multiple pin header locations.

swingstate commented

Thanks, I should have looked more closely at the pins. GND all over :). I'll give it a try and share my impressions on the OpenDTU-onbattery git.

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markusdd commented

I think this has been clarified, closing.

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