Unable to configure UART2 and UART4 in beaglebone black.

General Discussion
,
1

Hello,

I am trying to configure UART2 and UART4 in the DTS file as below.
But I am unable to loopback there uart’s.

When is pins are configured as GPIO(mode 7), pins are always high even when tried to toggle.

uart2_pins: pinmux_uart2_pins {
                pinctrl-single,pins = <
                        AM33XX_PADCONF(AM335X_PIN_MII1_CRS, PIN_INPUT_PULLUP, MUX_MODE6)
                        AM33XX_PADCONF(AM335X_PIN_MII1_RX_CLK, PIN_OUTPUT_PULLDOWN, MUX_MODE1)
                >;
        };
        uart4_pins: pinmux_uart4_pins {
                pinctrl-single,pins = <
                        AM33XX_PADCONF(AM335X_PIN_MII1_TXD3, PIN_INPUT_PULLUP, MUX_MODE3)
                        AM33XX_PADCONF(AM335X_PIN_MII1_TXD2, PIN_OUTPUT_PULLDOWN, MUX_MODE3)
                >;
        };

&uart2 {
        pinctrl-names = "default";
        pinctrl-0 = <&uart2_pins>;
        status = "okay";
};

&uart4 {
        pinctrl-names = "default";
        pinctrl-0 = <&uart4_pins>;
        status = "okay";
};

Thanks in advance,
Kasturi.

2 
$ cat /boot/uEnv.txt
1 Like
3

@Kasturi

Also, another helpful tool is setting GPIOs low in .dts. This may help in the long run.

Seth