Operation

Software

Note

Make sure you have installed the control software as described in Software Commissioning.

Using multiple USB-SD-Muxes on a single host is considered a common use case. Thus, it is a good practice to access a USB-SD-Mux via the /dev/usb-sd-mux/id* symlinks created by the provided udev-rule. The following examples are based on a USB-SD-Mux with the ID 000000000101.

If you have set up the udev rule to grant access to the USB-SD-Mux control interface to your current user, you should be able to use it as shown below. Otherwise you may need to use the sudo command.

• To multiplex the Micro-SD-Card to the DUT

  $ usbsdmux /dev/usb-sd-mux/id-000000000101 DUT
  

Important

The card insertion detection signal on the DUT's SD card controller is not toggled, when you switch into DUT-mode on the USB-SD-Mux. Therefore, you either need to signal this to the DUT externally or simply power-cycle the DUT.

• To multiplex the Micro-SD-Card to the host:

  $ usbsdmux /dev/usb-sd-mux/id-000000000101 host
  

• To disconnect the micro SD card from DUT and Host:

  $ usbsdmux /dev/usb-sd-mux/id-000000000101 off
  

• To get the current status of the USB-SD-Mux:

  $ usbsdmux /dev/usb-sd-mux/id-000000000101 get
  off
  

Note

The default state of USB-SD-Mux is off.

The block device of an USB-SD-Mux is symbolically linked as

/dev/disk/by-id/usb-LinuxAut_sdmux_HS-SD_MMC_*-0:0

Tool Integration

The labgrid project has support for the USB-SD-Mux. See labgrid's documentation for more details.