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BMP280 Help!

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RobOnk
(@robonk)
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Joined: 4 years ago
Posts: 3
Topic starter  

Please help! I'm trying to get my bmp280 pressure sensor to work with no luck. Even using the i2c scanner to read the address is not possible, the data line seems to be a garbled mess. I thought I had a bad module, so I bought another one, does the same thing. Using 3.3 supply and no pull-up resistors (although tried it with them). Wiring is ok. No problem with other i2c modules. Using with arduino uno. Thanks for any suggestions.


   
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 BLM
(@the-code-cobbler)
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Joined: 4 years ago
Posts: 14
 

 Hi,

I don't have any experience with that particular module...

That being said, I have used other I2C 'things' using the Arduino IDE..

You have probably checked the obvious possibilities, now is the time to check the not so obvious

1. Always double, triple check your code.. Check to see if your syntax is correct, even if the code compiles OK. I was working on a project with the MCP23017, as I made different last minute changes to the program I forgot to initialize the I2C comms..  The code compiled, but nothing worked..Forgetting a simple mcp.begin(); can cost you an hour.. Especially when you're a "code cobbler" like me.

2. Are you using a 3.3V BMP280 with a 5V Arduino? This would require logic level shifters...

3. Check all jumper wires and dupont cables for continuity, these break over time with many uses.

4. Check the quality of your DC power source with an Oscope (or DMM set to mVAC). If there is high enough ripple /noise on your DC this can cause bad comms on your I2C Bus.. You might try some small decoupling caps between VCC and ground very close to the BMP module..

I hope this helps,

Regards

 

 

 

--->The BLM<---


   
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 BLM
(@the-code-cobbler)
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Joined: 4 years ago
Posts: 14
 

One more thing...

Bill has an excellent troubleshooting video in his DroneBot YouTube series....   😉

--->The BLM<---


   
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(@jbeazy)
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Joined: 5 years ago
Posts: 18
 

I don't have experience with this sensor but out of curiosity I looked through the datasheet.  Do you have the "CSB" chip-select  pin available on your module? Datasheet page 28 says

"If CSB is connected to Vddio, i2c is active. If CSB pulled down, SPI is activated. After CSB pulled down once the i2c interface is disabled until next power-on reset.   …"


   
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RobOnk
(@robonk)
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Joined: 4 years ago
Posts: 3
Topic starter  

@the-code-cobbler

Excellent! Thanks for the tips! The one about logic level shifting sounds particularly interesting. 

 


   
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