We installed an Sierra Wireless EM7595 in a SMARC evaluation board V1.1A, with SMARC iMX95 V1.1A. But we can not detect the device on USB. Power LED is on. And the LED on M.2 Pin 10 give a blink sequence (1 second pulse). Why we see the device not on USB?
Hi, I’m the Toradex AI Assistant.
I might make mistakes or occasionally get you wrong. Our support team will step in if needed.
I’d be glad to help troubleshoot your Sierra Wireless EM7595 detection issue! To provide the most accurate guidance for your setup, could you let me know which OS and version you are running on your SMARC iMX95 system?
For detailed hardware information about your specific setup, you can use the tdx-info command to get comprehensive system details. You can find more information about this tool at: Getting Device Information with Tdx-Info | Toradex Developer Center
Initial Troubleshooting Steps
Based on the SMARC iMX95 documentation, here are some key points to consider:
USB Configuration on SMARC iMX95
The SMARC iMX95 features multiple USB interfaces (1):
- 2x USB 3.2 Host (Gen1)
- 1x USB 2.0 OTG
- 2x USB 2.0 Host
M.2 Slot Considerations
According to the SMARC specification, the M.2 Key B slot on the SMARC Development Board should support cellular modules (2). The blinking LED pattern you’re seeing (1 second pulse) typically indicates the modem is attempting to register with the network, which suggests it’s receiving power correctly.
Common Issues to Check
-
USB Hub Configuration: The SMARC iMX95 uses a USB hub implementation for multiple USB ports (3). Ensure the hub is properly configured in your OS.
-
Power Management: Verify that the USB power enable signals are properly configured (4). The SMARC specification includes USB enable/over-current protection signals that may need proper initialization.
-
Driver Support: Ensure your OS has the appropriate drivers for the Sierra Wireless EM7595.
Once you provide the OS version information, I can give you more specific troubleshooting steps and configuration guidance.
Best regards,
Toradex AI Assistant.
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Now it works. You must disconnect PCIe signals.
Solution Confirmed: PCIe/USB Signal Conflict
Great to hear it’s working now! Your solution highlights an important hardware design consideration for M.2 cellular modules on SMARC platforms.
Why Disconnecting PCIe Signals Resolved the Issue
The SMARC specification defines shared signal routing between PCIe and USB interfaces for M.2 slots(1). According to the SMARC iMX95 datasheet, the USB signals are routed through a USB hub configuration(1)(2), while PCIe signals share the same physical connector pins.
For cellular modules like the Sierra Wireless EM7595:
- USB Interface: Used for AT commands, data communication, and GPS functionality
- PCIe Interface: Typically not used by cellular modules (more common for WiFi cards)
Technical Background
The pin assignment documentation shows that USB signals (USB3+, USB3-, USB2+, USB2-) and PCIe signals (PCIE_A_TX+, PCIE_A_TX-, PCIE_A_RX+, PCIE_A_RX-) can conflict when both are enabled simultaneously(1)(3). The USB hub implementation routes cellular module communications through specific USB channels(2).
Key Takeaway
When using cellular modules in M.2 slots on SMARC platforms, ensure PCIe signals are properly disabled in your carrier board design or device tree configuration to prevent signal conflicts with USB communication paths.
This is valuable information for other users working with similar cellular module integrations on SMARC platforms.
Best regards,
Toradex AI Assistant.
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Wie kann ich den PCIe Port per Software abschalten?
Hey @inetronic!
I’d kindly ask you to always use English in the community so that everyone can understand the context of the thread.
That said, if I understood correctly, you’d like to disable the PCIe through software. To do this, you can create a device-tree overlay that disables the PCIe node by setting the status property to disabled.
As an example, you can find the respective PCIe node for our SMARC Development board here.
Best regards.