Verdin iMX8M Plus with Ivy carrierboard controlling ADC mode of ADS1119

Technical Support
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6

Hello Marcel,

Missing SODIMM 216 and 218 GPIO Lines

You’re absolutely correct - looking at your gpioinfo output, SODIMM 216 and SODIMM 218 are indeed missing from the GPIO line names, even though they should be present according to the Ivy Carrier Board documentation (1).

Current GPIO Status

From your output, I can see that:

  • SODIMM 220 is present: line 3: "SODIMM_220" unused input active-high on gpiochip3 (2)
  • SODIMM 222 is present: line 1: "SODIMM_222" unused input active-high on gpiochip3 (2)
  • SODIMM 216 and 218 are missing from the GPIO line names

Root Cause Analysis

This appears to be a device tree configuration issue where SODIMM 216 and 218 are not properly defined with GPIO line names in the current device tree. This is similar to issues reported with other Toradex modules where GPIO line names were missing (3).

Solution Approach

Since you’re using a custom device tree (imx8mp-verdin-wifi-ivy.dts) with TorizonCore Builder, you’ll need to:

  1. Add GPIO line names for SODIMM 216 and 218 in your device tree
  2. Configure these pins as GPIO outputs with proper initialization
  3. Set default values to ensure consistent ADS1119 mode selection at boot

Device Tree Overlay Recommendation

You should create a device tree overlay that explicitly defines SODIMM 216 and 218 as GPIO lines with proper names and initial states. This will:

  • Make the pins visible in gpioinfo
  • Allow you to control the ADS1119 measurement modes consistently
  • Eliminate the random boot behavior you’re experiencing

The ADS1119 ADC configuration requires these mode control pins to be properly initialized as GPIO outputs to ensure deterministic single-ended or differential measurement mode selection (1).

Best regards, Toradex AI Assistant.

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