# Snapdragon X2 Linux Mobile PC interfaces document The Snapdragon^®^ X2 Linux Mobile PC platform provides serial peripheral buses, PCIe links, and USB ports for connecting on-board and external devices. The platform groups its low-speed serial buses under the QUP v3 subsystem, provides five PCIe root complexes for high-bandwidth storage and connectivity, and exposes six USB interfaces for Type-C and Type-A devices. Each interface targets a distinct class of peripherals, from touchscreens and sensors to NVMe drives and displays. Use the following topics to identify which interface fits each use case, configure it across the required subsystems, and debug and troubleshoot the USB interface. ## Get started with the Snapdragon X2 interfaces Snapdragon X2 interfaces overview Learn about the peripheral, PCIe, and USB interface features. https://docs.qualcomm.com/doc/80-A0399-8/topic/product-overview.html Get started with the interface configuration Plan an interface configuration before you edit any source files. https://docs.qualcomm.com/doc/80-A0399-8/topic/get-started.html Snapdragon X2 interface architecture Understand how each interface block connects to the rest of the SoC. https://docs.qualcomm.com/doc/80-A0399-8/topic/architecture.html ## Configure the interfaces Configure the peripheral interfaces Enable I^2^C, SPI, UART, and QSPI on a QUP serial engine. https://docs.qualcomm.com/doc/80-A0399-8/topic/configure-peripheral-interfaces.html Configure the PCIe and USB interfaces Locate the PCIe firmware sources and enable a USB controller. https://docs.qualcomm.com/doc/80-A0399-8/topic/configure-pcie-usb-interfaces.html ## Debug and troubleshoot the USB interface Debug the USB interface Enable verbose logging, read DWC3 debugfs entries, and use JTAG. https://docs.qualcomm.com/doc/80-A0399-8/topic/debug-usb.html Troubleshoot the USB interface Resolve common USB configuration and compliance issues. https://docs.qualcomm.com/doc/80-A0399-8/topic/troubleshoot-usb.html ## References and resources References Find related documents and external resources. https://docs.qualcomm.com/doc/80-A0399-8/topic/references.html Last Published: Sep 17, 2026 [Next Topic Snapdragon X2 interfaces overview](https://docs.qualcomm.com/bundle/publicresource/80-A0399-8/topics/product-overview.md)