I just bought a hundred bucks worth of Quiic cables, endpoints, a device and adapters. The adapters were intended for my already purchased non-Quiic devices. However, the pinouts for an OLED display, a Bosch barometric pressure sensor, a SparkFun load cell amplifier and the SparkFun Quiic Adapter are all different from each other and can’t be directly connected with header pins. Pictures are attached. I have three questions:
1 - Why isn’t the SparkFun Load Cell Amplifier board compatible with the SparkFun Quiic Adapter?
2 - What devices should I expect the Quiic Adapter to be compatible with?
3 - For my incompatible devices, do I just use wire and glue the adapter to the device?
Ignore my first question. I assumed that the load cell amplifier is an I2C device but its digital interface is something non-standard. That’s why the pinout doesn’t match. It’s not supposed to.
I don’t recall the date but at some point 3 to 4 years ago sparkfun standardized the pin order for it’s i2c enabled boards to make them qwiic compatible. Boards before that day can vary in pinout.
There is no official worldwide standard for pin order so your mileage may vary on non sparkfun Boards.
One thing that might work for your situation is if two pins line up between the qwiic adapter and board, install header pins there but leave a gap so you can reroute the pins that don’t line up with a short bit of wire. The pin headers will provide a solid mounting point for the adapter while the wire jumps correct the pinout.
This pin mismatch also makes me sad. Apparently the GVCD pin-order is sometimes called the Philips/NXP style. I’m tempted to order a custom PCB from OshPark or something. But it seems silly. I wish that SparkFun could simply add another row of 0.1” holes to their QWIIC adapter, with the alternate clock/data pins swapped. Even AdaFruit’s very similar board has the through-hole order different than the pin-order.
There’s no standard for pin order, even if sparkfun added a second row of holes with an alternate order, it still wouldn’t fit every board. Just use a little bit of wire, that will adapt any board.
If that fits your use case, it might be the best way to go, other PCB manufacturers will even solder the JST connector on for you. If you need enough of them, it might end up being cheaper than buying boards from sparkfun anyway.
