Problem with accessing SparkFun MicroMod GNSS Function Board - NEO-M9N board via I2C

Development Boards MicroMod
1

Configuration:

SparkFun MicroMod Main Board - Double

SparkFun MicroMod Artemis Processor

Slot 0 : SparkFun MicroMod LoRa Function Board

Slot 1: SparkFun MicroMod GNSS Function Board - NEO-M9N board

Test script: Example3_Geoposition from SparkFun_u-blox_GNSS_v3;

Test works if no devices connected to the main board’s Qwiic connector.

Test works if one or two sensor boards (SparkFun Micro Absolute Digital Barometer - LPS28DFW (Qwiic)) connected directly to Qwiic connector on main bard.

Test doesn’t ! work if the same device connected via SparkFun QwiicBus Kit and the kit connected to Qwiic connector on the main board. Note, the sensor board accessible and works as expected when connected with QwiicBus Kit.

Please advise on how to fix the problem.

Thank you,

Dmitry

2

The qwiicbus devices use pull up resistors https://learn.sparkfun.com/tutorials/sp … e-overview by default, and likely so do your other sensors/boards (LPS28DFW, M9N).

Disable all but one set of pull-up resistors for any given i2c bus and you should be good :slight_smile:

(there are some on the qwiicbus , the sensors, the GPS device…disable by cutting the i2c trace on all except one device)

3

Hi -Russell,

Thanks for the response, I disabled pull-up resistors on GNSS board and I2C scanners detects device at 0x42 address (GNSS board I2C?), but example sketch fails to establish communication. I don’t want to cut pull-ups on other connected devices since the rest of the system works fine and I’d rather not risk breaking it … :slight_smile: .

I would like to try to establish communication over SPI, but can’t figure out SPI settings for the Function One slot. Could you please provide an examples (or point to one) which shows how to connect via SPI to a slot 1.

Thanks you,

Dmitry