HTU21D Temperature/Humidity Sensor Module

Products & Technology XIAO
#1

I am working with the HTU210D Humidity/Temperature sensor module. These specifically:
https://smile.amazon.com/gp/product/B07VRNW2X6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I have tried the Adafruit, Sparkfun and enjoyneering HTU21D libraries in my PlatformIO project but I cannot seem to get any of them to even initialize the interface. Subsequent calls all timeout with errors.

Has anyone got this module to work? I have 3V3, GND, SDA, SCL connected to the module and no other pins are being used. I am using SerialUSB for debug messages.

I have got other I2C devices to work on the XIAO, such as an OLED display after trying a couple libraries.

Thanks for any guidance. I am new to the XIAO and to Platform IO having just created a few projects.

#2

I found that the module I was using had pullup resistors (4700 ohm) for the I2C interface that required a solder jumper. Enabling those seems to have fixed the problem. All of my research, plus trial and error work has been educational. I will ALWAYS look for a problem with pullups now.