Disable BT

    Hello F&S team,


    in the default fus-image-std the serial port /dev/ttyLP1 seems not to be available. The datasheet of the imx93 mentions the following "UART_B is shared with WiFi/BT Module. If BT is used UART_B is not connected.". Makes sense, since by defaut the BT is registered. However, what's the most convenient way to disable Bluetooth?


    I've got a custom layer in yocto: /meta-<custom layer>/recipes-kernel/linux and tried to load a custom *.cfg in my linux-fus.bbappend to disable (=n) only the parameter CONFIG_BT_HCIUART and CONFIG_BT_NXPUART via KERNEL_CONFIG_FRAGMENTS += "bt-off.cfg". Probably the device tree picocoremx93.dts needs to be overwritten as well to comment out the line "#define CONFIG_PICOCOREMX93_UART_B_BT".


    It's not working so far. What's your suggestion resp. the recommended way? Thanks


    Best regards,

    BS

    Hello,


    it should be sufficient to uncomment CONFIG_PICOCOREMX93_UART_B_BT

    https://github.com/FSEmbedded/…%2BS/picocoremx93.dts#L57


    Normally you don't have to remove the driver from the defconfig.


    However, there are bridges on the PCB , that are not equipped by default, if the WLAN module is equipped, so the UART_B lanes are not connected to the board connector.


    Which version if the PicoCoreMX93 do you use?


    Your F&S Support Team

    Hello,


    we do have the PicoCore type PCoreMX93-SEN1 (Rev. 1.10).


    Specs:

    NXP i.MX93 Dual Cortex®-A55 @ 1.5GHz

    2GB LPDDR4, 8GB eMMC, Audio Codec, 2x

    Gbit LAN, 2x CAN, LVDS, RTC, Wi-Fi 6,

    Bluetooth 5.2, and 802.15.4, 2x U.FL,

    -40°C - +85°C, Linux


    However, I can not find this type on your website anymore, probably changed again.


    A Wi-Fi module is mounted on the PicoCore (label ublox, red sticker with antenna connectors).

    Quote

    However, there are bridges on the PCB , that are not equipped by default, if the WLAN module is equipped, so the UART_B lanes are not connected to the board connector.

    From my understanding this basically means that the serial port /dev/ttyLP1 (UARTB) is not available on PicoCore imx93 pcbs with Wi-Fi module? Right?


    Best regards,

    BS

    Hello,


    Quote

    However, I can not find this type on your website anymore, probably changed again.

    This is a customer specific Variant, so it is not listed on the website.

    Quote

    From my understanding this basically means that the serial port /dev/ttyLP1 (UARTB) is not available on PicoCore imx93 pcbs with Wi-Fi module? Right?

    Yes this is correct. The WLAN chip will drive the RX Pin of the UART so it might come to short circuits if both is connected.


    Your F&S Support Team

    Hello,


    ok thanks for the clarification.

    Quote

    This is a customer specific Variant, so it is not listed on the website.

    Sorry, my mistake.

    Quote

    Yes this is correct. The WLAN chip will drive the RX Pin of the UART so it might come to short circuits if both is connected.

    What could be a work around for this? We worked previously with the PicoCore imx8mm (+Wi-Fi, serial ports dev/ttymxc1-3) and wanted to switch over to the imx93 using the same components (incl. Wi-Fi and the renamed serial ports /dev/ttyLP1-3).


    Best regards,

    BS