6. UART

6.1. Introduction

AIO-3562JQ supports UART, RS232 and RS485 interfaces

• UART x 1

• RS485 x 2

• RS232 x 2

The UART is uart7, RS232 is converted from RK3562 uart8 and uart9, RS485 is converted from uart5 and uart6.

The serial interface diagram of the AIO-3562JQ development board is as follows:

6.2. DTS configuration

File kernel/arch/arm64/boot/dts/rockchip/rk3562-firefly-aio-3562jq.dtsi has the definition of uart related nodes:

/* RS485 */
&uart5 {
    status = "okay";
    pinctrl-names = "default";
    pinctrl-0 = <&uart5m1_xfer>;
};

&uart6 {
    status = "okay";
    pinctrl-names = "default";
    pinctrl-0 = <&uart6m0_xfer>;
};

&uart7 {
    status = "okay";
    pinctrl-names = "default";
    pinctrl-0 = <&uart7m0_xfer>;
};

/* RS232 */
&uart8 {
    status = "okay";
    pinctrl-names = "default";
    pinctrl-0 = <&uart8m0_xfer>;
};

&uart9 {
    status = "okay";
    pinctrl-names = "default";
    pinctrl-0 = <&uart9m1_xfer>;
};

The nodes on the hardware interface corresponding to the software are:

485A1/B1：   /dev/ttyS5
485A2/B2：   /dev/ttyS6
TX7/RX7：    /dev/ttyS7
232TX1/RX1:  /dev/ttyS8
232TX2/RX2:  /dev/ttyS9