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nrf52840 Feather with Motorwing
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Please be positive and constructive with your questions and comments.

nrf52840 Feather with Motorwing

by tHoagland on Fri Apr 09, 2021 11:08 am

Good morning,

I've working with an nrf52840 feather and the Stepper+DC Motor Featherwing. The two are connected directly together via the pin-headers, the solder connections all look fine, and I checked continuity between all of the shared pins (3.3v, GND, SCL, SDA) and it seems OK. When I try to initialize the Motorkit object:

import board
from adafruit_motorkit import MotorKit
kit = MotorKit(i2c=board.I2C())

I get a runtime error:

RuntimeError: SDA or SCL needs a pull up

The 10K pullup resistor comes installed on the Motor wing and I measured resistance between the SDA/SCL and 3.3V and got 10k/8k respectively (which I think is fine). When I run that same motor wing on a different model feather (M4 express), everything works as expected.

This leaves me wondering if there might be some chipset specific configuration that I need for the nrf52840.

Any thoughts?

tHoagland
 
Posts: 2
Joined: Sat Mar 27, 2021 6:53 am

Re: nrf52840 Feather with Motorwing

by dastels on Fri Apr 09, 2021 11:16 am

The first step is to make sure you're using the lastest CircuitPython and libraries.

You don't need pullups with the Feather nRF52840. This issue pops up now & then.

Dave

dastels
 
Posts: 6525
Joined: Tue Oct 20, 2015 3:22 pm

Re: nrf52840 Feather with Motorwing

by tHoagland on Fri Apr 09, 2021 11:32 am

Thanks Dave,

I am using the newest CircuitPython and Libraries. The pull up resistors on on the featherwing itself; do they need to be removed?

Any other suggestions?

tHoagland
 
Posts: 2
Joined: Sat Mar 27, 2021 6:53 am

Re: nrf52840 Feather with Motorwing

by dastels on Fri Apr 09, 2021 11:57 am

Adafruit FeatherWings and breakouts have the required pullups on them. You don't have to worry about them.

The error can can be a result of poor SDA/SCL connections. Continuity between the header pins doesn't necessarily mean continuity between the two boards. I would redo the soldering on the relevant pins.

Post a clear photo of the soldering if you'd like comment.

Dave

dastels
 
Posts: 6525
Joined: Tue Oct 20, 2015 3:22 pm

Please be positive and constructive with your questions and comments.