I'm doing a similar project as the link below that uses the Seeeduino XIAO, LCD display and the maxim blood oxygen sensor. I'm a little confused with the circuit connection this guy made.
Link to his project: https://www.instructables.com/Blood-Oxygen-Heart-Rate-Meter/#discuss
Pin 4 and 5 are the actual and the only SDA and SCL on the XIAO, which are already used by the maxim sensor according to his connection summary. But I can't understand how he used pin 8 and 10 for the SCL and SDA of the LCD display? I can't find anything in his code that assigns pin 8 or 10 as an additional SCL/SDA for the XIAO.
Source code can be found at: https://github.com/moononournation/BloodOxygenHeartRateMeter
I've read somewhere that two I2C devices (display and sensor) can be connected to the same SDA and SCL pin in parallel with a pull up resistor, but this seems to work differently.
I'm not sure what I missed but I would love to understand how he made pin 8 and 10 as additional SCL and SDA. Any help would be appreciated, Thank you :)