Usb And Pcie Modes - Quectel RM500Q-AE Manual

⚫ Keep the differential impedance of PCIe data trace as 85 Ω ± 10 %.
⚫
You must not route PCIe data traces under components or cross them with other traces.
3.7.2.3.9.2.

USB and PCIe Modes

RM500Q-AE&RM502Q-AE supports to communicate through both USB and PCIe interfaces, respectively
referring to the USB mode and the PCIe
USB Mode
⚫
Supports all USB 2.0/3.1 features
⚫
Supports MBIM/QMI/QRTR/AT
⚫
Communication can be switched to PCIe mode by AT command
USB is the default communication interface between RM500Q-AE&RM502Q-AE module and a host. To
use PCIe interface for the communication between a host, an AT command under USB mode can be
used. For more details about the AT command, see document [2].
It is suggested that USB 2.0 interface be reserved for firmware upgrade.
USB-AT-based PCIe Mode
⚫
Supports MBIM/QMI/QRTR/AT
⚫
Communication can be switched back to USB mode by AT command
When RM500Q-AE&RM502Q-AE module works at the USB-AT-based (switched from USB mode by AT
command) PCIe mode, it supports MBIM/QMI/QRTR/AT, and can be switched back to USB mode by AT
command. But the firmware upgrade via PCIe interface is not supported, so USB 2.0 interface must be
reserved for the firmware upgrade.
eFuse-based PCIe Mode
⚫
Supports MBIM/QMI/QRTR/AT
⚫
Supports Non-X86 systems and X86 system (supports BIOS PCIe early initial)
RM500Q-AE&RM502Q-AE can also be reprogrammed to PCIe mode based on eFuse. If the
communication is switched to PCIe mode by burnt eFuse, the communication cannot be switched back to
USB mode.
Note that if the host does not support firmware upgrade through PCIe, then RM500Q-AE&RM502Q-AE
USB 2.0 interface (Pin 7 and Pin 9) and two test points (VREG_L6E_1P8 and FORCE_USB_BOOT,
RM500Q-AE&RM502Q-AE_Hardware_Design
RM500Q-AE&RM502Q-AE Hardware Design
mode, as described below:
5G Module Series
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