So a year ago I bought a SparkFun Qwiic Starter Kit for Raspberry Pi (DEV-14459) which got stuffed into a box, unopened. Due to the stay at home order, my wife got us on a cleaning kick and the kit was discovered! Since I have a little free time now, I was excited to get everything plugged in and going. However, I’m not having much luck–i2detect doesn’t seem to see anything that is connected to it (on my Raspberry Pi 3B):
pi@raspberrypi:~ $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
I have tried all 4 ports on the Qwiic Hat, as well as different cables and two different Qwiic devices: SEN-14587 SparkFun Triple Axis Accelerometer Breakout - MMA8452Q (Qwiic) and the SparkFun Distance Sensor Breakout - RFD77402 (Qwiic). I don’t have a oscilloscope any more, so I can’t see if there is anything on the particular lines, but I have noticed that while the voltage on the 5V pin looks good, the voltage on the 3.3V pin does not–it is 0.4V with no device plugged in, and 1.42V with devices plugged in (and reads 1.42 at the device side as well).
I also installed a brand-new copy of the Raspbian Full image (which came with i2c-tools pre-installed), so I’m assuming that it is working correctly. I currently don’t have access to another Pi, so I can’t tell if it’s an issue with this Pi or not.
A bit of Google-fu says that there is no useful loopback facility for i2c, so that seems like a dead end idea.
Obviously I’m a bit outside the return window (and the DEV-14459 is backordered). So any advice as to how to troubleshoot this would be greatly appreciated, or perhaps a pointer to a replacement–is the DEV-15945 SparkFun Qwiic pHAT v2.0 for Raspberry Pi a suitable replacement?
Hi cmreigrut,
Sorry to hear you’re having trouble with your Qwiic HAT. Based on your description, it sounds like the voltage regulator on the HAT is not working properly. With the HAT plugged in and your Pi powered on, do you notice the regulator heating up excessively? If you inspect the regulator, does anything look off (eg. floating pins, bubbled plastic or anything)? Unfortunately, if the regulator is malfunctioning, there is not really an option to fix it without replacing that component and that will be more trouble than it is worth. If you have one of our Qwiic Jumper adapters like [this you can test the individual Qwiic boards to make sure the boards and your Pi’s I2C bus is working properly.
Lastly, for a replacement option, the Qwiic pHAT v2.0 is absolutely the recommended option for a HAT. We have a couple other Qwiic adapters for the Pi like the [Qwiic SHIM and a previous version of the [Qwiic pHAT. The primary differences between that and v2.0 of the Qwiic pHAT is we removed the voltage regulator and source 3.3V directly from the Pi, we added a 2-pin screw terminal to easily create a secure 5V source for other peripheral devices and we also added a button tied to GPIO 17 so you can access that pin to do things like [safely shutting down your Pi with the press of a button. We’ll have a more thorough rundown of both HATs in the [Hookup Guide.
I hope this info helps you troubleshoot the problem with your Qwiic HAT and points you in the right direction to either fix or replace it. Let us know if you need any other assistance with this issue and we would be happy to help!](Qwiic pHAT for Raspberry Pi Hookup Guide - SparkFun Learn)](Raspberry Pi Safe Reboot and Shutdown Button - SparkFun Learn)](https://www.sparkfun.com/products/15351)](SparkFun Qwiic SHIM for Raspberry Pi - DEV-15794 - SparkFun Electronics)](Flexible Qwiic Cable - Female Jumper (4-pin) - CAB-17261 - SparkFun Electronics)
No, no excessive heat nor any packaging abnormalities. I ordered the pHAT 2.0 as well as a jumper, so hopefully that will allow me to keep playing!
As an aside, shipping is kinda steep since I could (in ordinary times) have driven up to Boulder in half an hour and picked it up myself (and much faster)!
It definitely was the old HAT, as the new one works well. Still need to create drivers for several of the devices that don’t seem to have Pi drivers available, but the ones that have drivers work great.
Thanks for the debugging help!