Attempting to read BME280 sensor from WiPy 2.0 but having trouble ...

Questions and discussion about The WiPy 1.0 board and CC3200 boards.
Target audience: Users with a WiPy 1.0 or CC3200 board.
User avatar
pythoncoder
Posts: 3157
Joined: Fri Jul 18, 2014 8:01 am
Location: UK
Contact:

Re: Attempting to read BME280 sensor from WiPy 2.0 but having trouble ...

Post by pythoncoder » Sun Oct 28, 2018 5:03 pm

On a Pyboard, with nothing connected to the I2C bus, scan() returns instantly with []. I think you have some kind of hardware problem. To prove the point, disconnect your hardware and run scan() again.
Peter Hinch

sealyons
Posts: 13
Joined: Tue Oct 23, 2018 6:33 am

Re: Attempting to read BME280 sensor from WiPy 2.0 but having trouble ...

Post by sealyons » Sun Oct 28, 2018 5:15 pm

Yep, returns immediately if I disconnect everything. Any idea what type of hardware issue this might be?

User avatar
Roberthh
Posts: 1166
Joined: Sat May 09, 2015 4:13 pm
Location: Rhineland, Europe

Re: Attempting to read BME280 sensor from WiPy 2.0 but having trouble ...

Post by Roberthh » Sun Oct 28, 2018 5:18 pm

So maybe the pull-up resistors on SDA and SCL are missing. You can try to add 4.7 kOhm between SDL and Vcc and SDA and Vcc.

User avatar
pythoncoder
Posts: 3157
Joined: Fri Jul 18, 2014 8:01 am
Location: UK
Contact:

Re: Attempting to read BME280 sensor from WiPy 2.0 but having trouble ...

Post by pythoncoder » Sun Oct 28, 2018 5:29 pm

It is going to be hard for us to debug this remotely: either your hardware is broken or it is wired incorrectly. I'd put a multimeter on the data and clock lines: both should read 3.3V in the idle state. My guess is that one or both is being pulled low.
Peter Hinch

sealyons
Posts: 13
Joined: Tue Oct 23, 2018 6:33 am

Re: Attempting to read BME280 sensor from WiPy 2.0 but having trouble ...

Post by sealyons » Sun Oct 28, 2018 5:36 pm

With 4 lines, it's hard to imagine it's wired incorrectly. I can try to add pull-ups. I'll also check the voltage levels on SDA & SCL. However I'm late for an appt. so I'm done for the day. I really appreciate your help. I'll be back tomorrow.

Post Reply