Qwiic (SparkFun), STEMMA QT (Adafruit) and μŠup (LaskaKit, also written uŠup) are three names for the same four-pin JST SH connector with 1 mm pitch. They connect boards and sensors over the I2C bus without soldering: snap in the cable and daisy-chain the modules.
All three systems use the same pin order and wire colors, so cables and modules are interchangeable. Only the power differs – Qwiic and μŠup assume 3.3 V, STEMMA QT allows 3 to 5 V.
Key specs
- JST SH connector, 4 pins, 1.0 mm pitch (SM04B-SRSS-TB on the board, SHR-04V-S on the cable)
- pin order: GND, 3.3 V, SDA, SCL
- wire colors: black (GND), red (3.3 V), blue (SDA), yellow (SCL)
- 3.3 V power (Qwiic, μŠup), 3–5 V for STEMMA QT
- I2C bus – a cable can carry multiple modules, but each needs a different address
The pull-up resistors on SDA and SCL are usually right on the modules, often with a jumper to disconnect them. When many modules are chained, the pull-ups end up in parallel and the resulting resistance drops – so on a longer chain, disable the pull-ups on most modules.
Qwiic / STEMMA QT / μŠup Connector Pinout
The connector is drawn looking into the opening with the board at the bottom – pin 1 (GND) is on the left. The wire colors are the same for all three systems.
| Pin | Signal | Wire color | Note |
|---|---|---|---|
| 1 | GND | black | Ground |
| 2 | 3V3 | red | Power: Qwiic and μŠup 3.3 V, STEMMA QT 3–5 V (modules have their own regulator) |
| 3 | SDA | blue | I2C bus data |
| 4 | SCL | yellow | I2C bus clock |
Compatibility with Other Connectors
Several manufacturers use a four-pin I2C connector. Not all of them are wired the same, though:
| System | Connector | Pin order | Power | With Qwiic |
|---|---|---|---|---|
| Qwiic (SparkFun) | JST SH 1 mm | GND, 3V3, SDA, SCL | 3.3 V | – |
| STEMMA QT (Adafruit) | JST SH 1 mm | GND, V+, SDA, SCL | 3–5 V | direct |
| μŠup (LaskaKit) | JST SH 1 mm | GND, VCC, SDA, SCL | 3.3 V | direct |
| EasyC (Soldered), Modulino (Arduino) | JST SH 1 mm | GND, 3V3, SDA, SCL | 3.3 V | direct |
| Grove (Seeed) | 2 mm with latch | same signal order | 3.3 or 5 V | with adapter |
| M5Stack Port A | Grove (HY2.0) | GND, 5V, SDA, SCL | 5 V | with adapter, watch out for 5 V |
| STEMMA (Adafruit, 4 pins) | JST PH 2 mm | same signal order | 3–5 V | with adapter |
| I2C port on LOLIN (Wemos) boards | JST SH 1 mm | GND, SDA, SCL, 3V3 | 3.3 V | no – different order |
| Gravity I2C (DFRobot) | JST PH 2 mm | VCC, GND, SCL, SDA | 3.3–5 V | no – different order |
With Grove, watch the numbering: Seeed numbers from the SCL pin, so its pin 1 is at the opposite end from Qwiic’s. The wire order is the same, though – a 2 mm to 1 mm adapter is all you need. The Grove wiring is on the Grove pinout page.
Pin 1 on the Cable
In its cable drawing, SparkFun numbers the pins of the cable connector in reverse (1 = yellow, 4 = black). This doesn’t change the wiring – go by the colors: the black wire is always GND and the yellow one SCL.
What to watch out for
- Qwiic and μŠup are 3.3 V only. Don’t connect a module without a regulator to 5 V.
- The I2C port on LOLIN (Wemos) boards has the same connector but a different pin order – a Qwiic cable would put 3.3 V on the module’s SCL and SDA on its power pin.
- DFRobot Gravity has a larger connector and reversed power – don’t connect it without an adapter.
- Pull the cable out by the connector, not by the wires – the thin wires easily tear out of the housing.
- I2C is meant for short distances, a few tens of centimeters at most. For longer cables, use a bus extender.
Projects with μŠup and Qwiic on chiptron.eu/
These projects and articles use modules with the μŠup (Qwiic, STEMMA QT) connector:
- Sensirion CO2 sensors – SCD41 on a module with μŠup, Qwiic and STEMMA QT connectors
- SEN66 in practice – adapter from the sensor connector to μŠup and code for ESP32
- Educational platform with ESP32-S3 – base board with a STEMMA QT / Qwiic / μŠup connector
More pinouts
See all pinouts on the Pinouts page.