Solution to Telit Modules Connectivity Issue on LattePanda 3 Delta

Hello LattePandaians,

We're excited to share a solution from community member Hendrik, who has found a fix for the connectivity issues with Telit modules.

Hendrik discovered that the Telit modules' SIM card detection does not comply with the M.2 specification. The UIM_PRESENT pin is set to active low by default, causing detection issues.

Here's the key information from the Telit FN990 hardware guide:

"Unlike the M.2 specification, the UIM_PRESENT pin is set to active low (Inserted) by default for the Telit unified function. So FN990 will detect the SIM card insertion when UIM_PRESENT input is changed from a logic 1 to a logic 0. If the user wants to change UIM_PRESENT pin to active high (inserted), please refer to AT#SIMINCFG of FN990 AT Commands Reference Guide."

To fix this, reverse the SIM detection logic using the AT command guide:

1. Open the AT command interface on your Telit module.
2. Find the AT#SIMINCFG command in the FN990 AT Commands Reference Guide.
3. Execute the AT#SIMINCFG command to switch the UIM_PRESENT pin to active high.
4. Save and reboot the module for changes to apply.

This should enable proper SIM detection in the LattePanda 3 Delta, allowing you to connect to cellular networks.

Thanks to Hendrik for his diligent work. If you have questions or need help, please reply to this post.

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