Website Error?: STEMMA / Gravity compatibility

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Minxster
 
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Website Error?: STEMMA / Gravity compatibility

Post by Minxster »

I did find an old topic on this subject, but nothing seems to have come of it, at the topic is now close. Anywho, I think someone needs to take a look at this webpage?

https://learn.adafruit.com/introducing- ... ot-gravity

It seems to indicate that STEMMA (Grove) and Gravity connectors are compatible. But plugging such connectors/sockets together would cause all sorts of problems as each pin is wired differently. I know that some modules/devices have reversed polarity protection, but this shouldn't be relied upon.

At least for the sake of education/schools, surely there should be clear guidance on the page to explain that though the to standards (if I can call them that) are loosely compatible, they do indeed need a full re-wire of all pin, before us. Maybe even links to by cables that already switch the pins?

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adafruit_support_mike
 
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Re: Website Error?: STEMMA / Gravity compatibility

Post by adafruit_support_mike »

Minxster wrote: Wed Aug 17, 2022 7:44 amIt seems to indicate that STEMMA (Grove) and Gravity connectors are compatible.
The page says 4-pin STEMMA is only compatible with 4-pin I2C Gravity boards. If you're referring to Gravity UART or other 4-pin connections, the warning is already there.

As far as we know, 3-pin STEMMA is generally compatible with 3-pin Gravity.

If you know of 4-pin I2C Gravity boards that aren't compatible with STEMMA, or 3-pin Gravity boards that aren't compatible, please post links to them and we'll take a look.

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Minxster
 
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Re: Website Error?: STEMMA / Gravity compatibility

Post by Minxster »

I suppose its this sentence that seem strange to me?
You can plug the larger 4-pin STEMMA cables/devices/controllers into Gravity I2C devices/controllers just fine and vice-versa.
As the 4 pin Gravity I2C connectors do not have the same pin arrangements?

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gbeland
 
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Re: Website Error?: STEMMA / Gravity compatibility

Post by gbeland »

I thought it meant this cable would work:
4-pin JST PH to JST SH Cable - STEMMA to QT / Qwiic - 200mm long

Is this not true?

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Minxster
 
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Re: Website Error?: STEMMA / Gravity compatibility

Post by Minxster »

gbeland wrote: Thu Aug 18, 2022 2:56 pm I thought it meant this cable would work:
4-pin JST PH to JST SH Cable - STEMMA to QT / Qwiic - 200mm long

Is this not true?
Sadly now. The Gravity connection has +/- pins are reversed, as well as the clock/data are reversed.

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gbeland
 
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Re: Website Error?: STEMMA / Gravity compatibility

Post by gbeland »

Thanks for the reply. I'll just jumper them over. I am going to try to get the https://www.dfrobot.com/product-2001.html to work on CP.

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