18. UART_ioctl

18.1. Overview

This example shows the modes available when using UART1.

18.2. Setup

• See uart_echo.

• Usage - Connect gpio3, gpio4, and GND to TXD, RXD, and GND on a USB to TTL adapter respectively. - Download and compile customer_app/sdk_app_uart_ctl. - Open one serial terminal at 115200 baud for sending and receiving UART messages, and another at 2000000 for logging. For instance, with case1, you can enter 123456789abcdef in the first window, see the reply, and also print out the amount of data received to the second window.

18.3. Examples

aos_ioctl IOCTL_UART_IOC_WAITRD_MODE and IOCTL_UART_IOC_WAITRDFULL_MODE:

while (1) {
    //log_info("ready to read.\r\n");
    waitr_arg.buf = buf_recv;
    waitr_arg.read_size = sizeof(buf_recv);
    waitr_arg.timeout = 0;
    res = aos_ioctl(fd, IOCTL_UART_IOC_WAITRD_MODE, (unsigned long)(&waitr_arg));
    //res = aos_ioctl(fd, IOCTL_UART_IOC_WAITRDFULL_MODE, (unsigned long)(&waitr_arg));
    if (res > 0) {
        log_info("%s name.length = %d:\r\n", name, res);
        aos_write(fd, buf_recv, res);
    }
}

• case1: waitr_arg.timeout = 0 and aos_ioctl(fd, IOCTL_UART_IOC_WAITRD_MODE, (unsigned long)(&waitr_arg)) make it so that when all available data or sizeof(buf_recv) is read the length is returned immediately. aos_ioctl(fd, IOCTL_UART_IOC_WAITRDFULL_MODE, (unsigned long)(&waitr_arg)) has the same usage as IOCTL_UART_IOC_WAITRD_MODE.

• case2: waitr_arg.timeout = AOS_WAIT_FOREVER and aos_ioctl(fd, IOCTL_UART_IOC_WAITRD_MODE, (unsigned long)(&waitr_arg)) make it so that it will wait for all available data or sizeof(buf_recv) to be read, and when there is no data available it will return immediately. aos_ioctl(fd, IOCTL_UART_IOC_WAITRDFULL_MODE, (unsigned long)(&waitr_arg)) means to wait for sizeof(buf_recv) to be read and then return.

• case3: waitr_arg.timeout = 5000 and aos_ioctl(fd, IOCTL_UART_IOC_WAITRD_MODE, (unsigned long)(&waitr_arg)) make it so that it will wait up to 5 seconds for all available data or sizeof(buf_recv) to be read, and when there is no data available it will return immediately. aos_ioctl(fd, IOCTL_UART_IOC_WAITRDFULL_MODE, (unsigned long)(&waitr_arg)) means to wait up to 5 seconds for sizeof(buf_recv) to be read and then return.

aos_ioctl UART_IOC_BAUD_MODE:

aos_ioctl(fd, IOCTL_UART_IOC_BAUD_MODE, 9600);

In the above, 9600 is the baud rate.

aos_ioctl IOCTL_UART_IOC_READ_BLOCK and IOCTL_UART_IOC_READ_NOBLOCK:

while (1) {
    length = aos_read(fd, buf_recv, sizeof(buf_recv));
    if (length > 0) {
        log_info("%s name.length = %d:\r\n", name, length);
        aos_write(fd, buf_recv, length);
    }
    vTaskDelay(500);
    log_info("test.\r\n");
    count++;

    if (count == 5) {
        log_info("set noblock.\r\n");
        aos_ioctl(fd, IOCTL_UART_IOC_READ_NOBLOCK, 0);
    }

    if (count == 10) {
        log_info("set block.\r\n");
        aos_ioctl(fd, IOCTL_UART_IOC_READ_BLOCK, 0);
    }
}

aos_ioctl(fd, IOCTL_UART_IOC_READ_BLOCK, 0) makes it so once sizeof(buf_recv) is read it will return, but otherwise it will wait. aos_ioctl(fd, IOCTL_UART_IOC_READ_NOBLOCK, 0) makes it so it will return once all available data or sizeof(buf_recv) is read.