MCP9601 & Raspberry pi 400 detects once then doesn't detect

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rrkappes
 
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MCP9601 & Raspberry pi 400 detects once then doesn't detect

Post by rrkappes »

I'm using a MCP9601 with a Raspberry Pi 400 to try to measure some temperatures.

On the good side, the power light on the board lights up and it detects when I run i2cdetect -y 1. On the bad side it only does this once and won't detect again UNLESS I disconnect and reconnect power to the MCP9601 and reconnect it. If I do that it detects again, once. Any ideas?

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by adafruit_support_carter »

Are you using one of the breakouts?
https://www.adafruit.com/product/5165

How is it connected to the Pi 400?

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by rrkappes »

I am indeed.

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by rrkappes »

The breakout board is soldered to a header and the pins are installed into a breadboard. From there I'm using jumper wires to connect it to the appropriate pins on a T-cobbler which is connected via a ribbon cable to the Pi 400. I tried connecting a second one via a Stemma QT cable and using one of the address pins to set the address to 0x60. In that case both detect the first time and then don't usually detect until power drops. However, occasionally on or the other will show up after multiple attempts.

I also wired the breakout directly to some jumper wires and connected them to the ribbon cable directly (It was what I had on hand) and I got the same result.

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by adafruit_support_carter »

OK, that sounds fine. Some sensors can do weird things when scanning. What if you ignore the scan behavior and just try using the sensor as shown here:
https://learn.adafruit.com/adafruit-mcp ... -3101130-4

Does it work OK in general?

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by rrkappes »

No. When trying to use the python sample code I either get error 121 (remote IO error) or a no I2C device found error 67. The error also occurs with a Raspberry Pi 4, so I suspect it's either a problem with my wiring or the breakout board itself.

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by adafruit_support_carter »

OK, might be connection related then. Can you post a photo showing your setup with the MCP9601 connected to the Pi 400.

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by rrkappes »

Here's the setup. I have two boards connected, but the issue exists with one or two boards.
IMG_2992.JPEG
IMG_2992.JPEG (869.09 KiB) Viewed 134 times

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by adafruit_support_carter »

Thanks. I'm thinking this might be a soldering issue. By any chance, did you get one of these STEMMA QT cables?
https://www.adafruit.com/product/4209

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by rrkappes »

I've ordered one. I'll know if that solves it soon.

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by adafruit_support_carter »

OK, thanks. If you're willing to wait until it arrives then we can pick this up then. Having that cable will let you go directly from the breakout's STEMMA QT connector to the T-cobbler and remove any soldering issues from the mix.

Let us know what happens!

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Re: MCP9601 & Raspberry pi 400 detects once then doesn't det

Post by rrkappes »

Welp. I decided to try another library and found that once I corrected it to support the 9601 (by adding support for the 9601 chip ID of 0x41) to the library located here I get good functionality out of the chip.

https://pypi.org/project/mcp9600/

I looked at the adafruit library and it appears to have added support for this already, but it still doesn't work on the breakout board, so obviously something subtle is going on. As it stands, I'll be able to do what I need to using this other library, but I still want to understand why the adafruit library isn't working for me.

EDIT: A previous version of this post included a link to the wrong library

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