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AM6548: some issues about wkup_uart0

Part Number: AM6548

Hi,

We had seen the post issue here:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1121582/am6548-using-all-uarts-on-linux/4161866?tisearch=e2e-quicksearch&keymatch=all-uarts-on-linux#4161866

1.How to stop this sysfw's output with wkup_uart0? Our application will take advantage of  this wkup_uart0 , so....

2. the baud rate of this wkup_uart0 was not right, if other devices want to communicate this wkup_uart0 normally, we should configure it in double speed baud rate, for example:am6548--9600 / other devices --19200

 how to fix this bug?

Thanks

Kenn

  • Hi Ken,

    1.How to stop this sysfw's output with wkup_uart0? Our application will take advantage of  this wkup_uart0 , so....

    When you compile uboot, you can either not define ENABLE_TRACE in the 'make' command line, or remove 'BOARDCFG_TRACE_DST_UART0' in <SDK>/board-support/k3-image-gen-2022.01/soc/am65x/evm/board-cfg.c

    2. the baud rate of this wkup_uart0 was not right, if other devices want to communicate this wkup_uart0 normally, we should configure it in double speed baud rate, for example:am6548--9600 / other devices --19200

    This sounds like software bug. Please share the details how you enabled wkup_uart0, then I will try to reproduce the issue and look into it.

  • Thanks Bin Liu,

    related wkup_uart0 setting in dts list as follow:

    .......

    wkup_uart4_pins_default: wkup_uart4_pins_default {
                    pinctrl-single,pins = <
                            AM65X_WKUP_IOPAD(0x00a0, PIN_INPUT_PULLUP, 0) /* (AB1) WKUP_UART0_RXD */
                            AM65X_WKUP_IOPAD(0x00a4, PIN_OUTPUT_PULLDOWN, 0) /* (AB5) WKUP_UART0_TXD */
                    >;
            };

    UART4EN_pins_default: UART4EN_pins_default {
                    pinctrl-single,pins = <
                            AM65X_IOPAD(0x00e8, PIN_OUTPUT, 7) /* (AF23) PRG1_PRU0_GPO2.GPIO0_58 UART4_EN_RTS*/
                    >;
            };

    .......

    &wkup_uart0 {
            pinctrl-names = "default";
            pinctrl-0 = <&wkup_uart4_pins_default &UART4EN_pins_default>;
            rs485-rts-active-high;
            rs485-rts-delay = <0 0>;
            rts-gpios = <&main_gpio0 58 GPIO_ACTIVE_HIGH>;
            linux,rs485-enabled-at-boot-time;
            status = "okay";
    };

    .......

    Thanks

    Kenn

  • Hi, Bin Liu,

    is this info enough for you to reproduce this issue? if not, please let us know

    Thanks

    Kenn

  • Bin,

    Do you think it is a bug of wrong configuration in sysfw like that of AM64x?

    https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1176841/am6442-mcu-uart-bard-rate

  • Bin,

    Customer change the clock-frequency to 96MHz, then wkup_uart baudrate is right as configurated.

    the k3-am65-mcu.dtsi mcu_uart0  clock-frequency = <96000000>; which is configured to be same as sysfw already. but the k3-am65-wakeup.dtsi did not change, suggest to fixed it in SDK.

    diff --git a/arch/arm64/boot/dts/ti/k3-am65-wakeup.dtsi b/arch/arm64/boot/dts/ti/k3-am65-wakeup.dtsi

    index ed42f13e7663..4094d5c42274 100644

    --- a/arch/arm64/boot/dts/ti/k3-am65-wakeup.dtsi

    +++ b/arch/arm64/boot/dts/ti/k3-am65-wakeup.dtsi

    @@ -53,7 +53,6 @@ wkup_uart0: serial@42300000 {

    reg-shift = <2>;

    reg-io-width = <4>;

    interrupts = <GIC_SPI 697 IRQ_TYPE_LEVEL_HIGH>;

    - clock-frequency = <48000000>;

    + clock-frequency = <96000000>;

    current-speed = <115200>;

    power-domains = <&k3_pds 150 TI_SCI_PD_EXCLUSIVE>;

    };

  • Thank Tony and Bin Liu for your help!

    Kenn