##Problem description The pin TXD (PA7/S16) on serial port __/dev/ttyS3__ doesn't work. ##Solution Change on __arch/arm/boot/dts/acme-aria.dts__ this section:

spi0: spi@f0000000 {
	status = "okay";
	cs-gpios = <&pioA 14 0>, <&pioA 7 0>, <0>, <0>;

	device@0 {
		compatible = "spidev";
		// spi-max-frequency = <50000000>;  // 50 MHz
		spi-max-frequency = <5000000>;	    // 5 MHz
		reg = <0>;
	};

	device@1 {
		compatible = "spidev";
		// spi-max-frequency = <50000000>;  // 50 MHz
		spi-max-frequency = <5000000>;	    // 5 MHz
		reg = <1>;
	};
};

in:

spi0: spi@f0000000 {
	status = "okay";
	cs-gpios = <&pioA 14 0>, <0>, <0>, <0>;

	device@0 {
		compatible = "spidev";
		// spi-max-frequency = <50000000>;  // 50 MHz
		spi-max-frequency = <5000000>;	    // 5 MHz
		reg = <0>;
	};

};

In this way the PA7 pin is used for the __/dev/ttyS3__ instead of CS od SPI0.