MonkeyFist
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Joined: Mon Oct 22, 2012 8:00 pm

Well known I2C addresses

Thu Mar 22, 2018 1:53 am

Is there a list of well known I2C addresses? I have a pi camera, pi display and a PiModules PIco UPS. I think I have a conflict. I know the PiModule address range, but cannot find the others.

6by9
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Re: Well known I2C addresses

Thu Mar 22, 2018 9:46 am

MonkeyFist wrote:
Thu Mar 22, 2018 1:53 am
Is there a list of well known I2C addresses? I have a pi camera, pi display and a PiModules PIco UPS. I think I have a conflict. I know the PiModule address range, but cannot find the others.
The camera and display are on i2c-0 and addressed by the GPU firmware (not the Linux kernel). Assuming the Pico UPS is connected to i2c-1 (it appears to be from "i2cdetect -y 1" in the docs), then there should be no conflicts at all.

And no, there isn't really a list of I2C addresses as many devices can be reconfigured to alternate addresses. For info, the V1 camera is 0x36, the V2 is on 0x10 and 0x64, whilst the display is on 0x38 and 0x45.
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MonkeyFist
Posts: 8
Joined: Mon Oct 22, 2012 8:00 pm

Re: Well known I2C addresses

Thu Mar 22, 2018 1:41 pm

Thanks, much appreciated.

Something I am doing is causing an interference. I have to do some troubleshooting.
I2cdetect reports zeroes at all ports when I plug in the camera (rev 1.3). Cabling or other problem.

Thanks!

6by9
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Raspberry Pi Engineer & Forum Moderator
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Re: Well known I2C addresses

Thu Mar 22, 2018 4:53 pm

MonkeyFist wrote:
Thu Mar 22, 2018 1:41 pm
Something I am doing is causing an interference. I have to do some troubleshooting.
I2cdetect reports zeroes at all ports when I plug in the camera (rev 1.3). Cabling or other problem.
If you've got the display connected as well, you do NOT need the SCL and SDA lines connected from GPIOs 2&3 to the display board except on the original model A&B. If you do then you will have bridged the two I2C busses and that will cause issues. Annoyingly several 3rd party instructions for the display still tell you to connect them.
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
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MonkeyFist
Posts: 8
Joined: Mon Oct 22, 2012 8:00 pm

Re: Well known I2C addresses

Thu Mar 22, 2018 5:13 pm

Ah.... Could be the problem. Thanks for the info - I'll check as soon as I get back to the lab. I really appreciate the help.

Mike

GordonTGopher
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Re: Well known I2C addresses

Thu Mar 22, 2018 7:58 pm

https://pinout.xyz has the I2C addresses for many add on boards.

Gordon

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Douglas6
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Re: Well known I2C addresses

Thu Mar 22, 2018 8:10 pm

Adafruit has fairly extensive list of general I2c addresses: https://learn.adafruit.com/i2c-addresses/the-list

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