I2C Multiplexer sup...
 
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[Solved] I2C Multiplexer support  

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carboncycle
(@carboncycle)
Active Member
Joined: 6 months ago
Posts: 12
November 28, 2019 5:52 pm  

I have noticed that in the Buster release of the Raspbian distribution has some significant changes in the Device Tree Overlays.   One of the changes seems to be a way to specify the bus number for the GPIO software I2C rather than having to accept a dynamically generated number.  And the overlay for I2C mux has removed the specific PCA9548 overlay for one that supports a few devices with the same overlay.

I haven't had time yet to review what has changed in the details behind the new overlay implementations - however I'll be looking at it over the next couple of months and update the overlays I have provided  ( I'm Theoi-Meteoroi on Github ) since v8.x and later are rather specific to Buster.

I also need to spend some time reviewing all the work Kyle has been putting in - and play with some of the newer features. 


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Kyle Gabriel
(@kylegabriel)
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Joined: 5 years ago
Posts: 193
December 12, 2019 4:47 pm  

Thanks for that. I've made a lot of cosmetic updates to the dashboard (multi-dashboard support, drag-n-drop) and finally pulled docker into master. There's still a lot to do with that, but it's a nice addition that should make for some interesting projects with users who unwittingly choose not to use a Raspberry Pi. I can't wait for the docker issue reports.

Mycodo Developer


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carboncycle
(@carboncycle)
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Joined: 6 months ago
Posts: 12
January 28, 2020 8:55 pm  

I checked the Buster release and the dtbo doesn't work, at least when I tried.   It seems the I2C support has changed enough to look alot closer, however that hasn't fixed the clock stretch problem I think.   The work-around for working with slow devices is to slow the clock to 10khz.    I'll see what can be done to salvage the GPIO-I2C mux.


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carboncycle
(@carboncycle)
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Joined: 6 months ago
Posts: 12
March 28, 2020 6:47 pm  

I have released an update to the 9548 overlay.  I have tested only on Pi-4 v1.2. 


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Kyle Gabriel
(@kylegabriel)
Member Admin
Joined: 5 years ago
Posts: 193
March 28, 2020 6:56 pm  

Excellent! Thanks for that. I'll test it with a Pi 3.

 

Mycodo Developer


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carboncycle
(@carboncycle)
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Joined: 6 months ago
Posts: 12
March 29, 2020 1:40 am  

I tested using the script on a Pi 3B+ and it worked as expected.  Seems to be a suitable replacement.


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