MA35D1 串口最大波特率支持多少

用non-os代码进行internal loop back测试是可以达到TRM 所描述的数值，而在Linux我们测试情况是FIFO trigger level 设置为0x30，波特率为6Mbps，在IoT板子 UART10把rx和tx短接进行2K Bytes自发自收100次是正常的。

FIFO trigger level 设置为0x30方法：

1. 驱动

output/build/linux-custom/drivers/tty/serial/ma35d1_serial.c

ma35d1serial_startup()里面

serial_out(up, UART_REG_FCR, serial_in(up, UART_REG_FCR) | 0x10 | 0x20000);

改为

serial_out(up, UART_REG_FCR, serial_in(up, UART_REG_FCR) | 0x30 | 0x20000);

2. 设备树

output/build/linux-custom/arch/arm64/boot/dts/nuvoton/ma35d1.dtsi里面做以下修改

assigned-clocks = <&clk UART10_MUX>;

assigned-clock-parents = <&clk SYSCLK1_DIV2>;

uart10:serial@407A0000 {

                compatible = "nuvoton,ma35d1-uart";

                reg = <0x0 0x407A0000 0x0 0x10000>;

                interrupts = <GIC_SPI 95 IRQ_TYPE_LEVEL_HIGH>;

                clocks = <&clk UART10_GATE>;

                port-number = <10>;

                pdma-enable = <0>;

                assigned-clocks = <&clk UART10_MUX>;

                assigned-clock-parents = <&clk SYSCLK1_DIV2>;

                status = "disabled";

        };

3. 波特率修改方式：

static int open_port(const char *portname)

{

    struct sigaction sa;

    int portfd;

    struct termios to;

    if((portfd=open(portname,O_RDWR | O_NOCTTY)) < 0 )

    {

           printf("open serial port %s fail \n ",portname);

           return portfd;

    }

    /*get serial port parnms,save away */

    tcgetattr(portfd,&newtios);

    memcpy(&oldtios,&newtios,sizeof newtios);

    /* configure new values */

    cfmakeraw(&newtios); /*see man page */

    newtios.c_iflag |=IGNPAR; /*ignore parity on input */

    newtios.c_iflag &= ~(IXON | IXOFF | IXANY);

    //newtios.c_iflag |= (INPCK | ISTRIP); // for test

    newtios.c_oflag &= ~(OPOST | ONLCR | OLCUC | OCRNL | ONOCR | ONLRET | OFILL);

    newtios.c_cflag = CS8 | CLOCAL | CREAD;

    //newtios.c_cc[VMIN]=1; /* block until 1 char received */

    newtios.c_cc[VMIN]=0xff;

    newtios.c_cc[VTIME]=0; /*no inter-character timer */

    newtios.c_iflag |= CRTSCTS;

    /* register cleanup stuff */

    atexit(reset_tty_atexit);

    memset(&sa,0,sizeof sa);

    sa.sa_handler = reset_tty_handler;

    sigaction(SIGHUP,&sa,NULL);

    sigaction(SIGINT,&sa,NULL);

    sigaction(SIGPIPE,&sa,NULL);

    sigaction(SIGTERM,&sa,NULL);

    /*apply modified termios */

    saved_portfd=portfd;

    tcflush(portfd,TCIFLUSH);

    tcsetattr(portfd,TCSADRAIN,&newtios);

    ioctl(portfd, TCGETS2, &tio);

    tio.c_cflag &= ~CBAUD;

    tio.c_cflag |= BOTHER;

    tio.c_ispeed = 6000000;

    tio.c_ospeed = 6000000;

    ioctl(portfd, TCSETS2, &tio);

    return portfd;

}

执行/uart_demo_rx_tx

脚本：

#!/bin/sh

for i in $(seq 1 100)

do

  echo "Running command: $i"

  /uart_demo_rx_tx

  sleep 1

done