F133 RTSCTS LINE

[emresensoy]

Hi. I couldn't activate the RTS and CTS lines on the Mango pi sparrow F133 board. If I activate RTSCTS from the termios properties in the program (attr.c_cflag |= CRTSCTS;), it doesn't send data from the Tx line either.
If I deactivate RTSCTS (attr.c_cflag &= ~CRTSCTS;), it sends data but doesn't make the RTS line 0.

I'm watching the lines with a logic analyzer. I see that the CTS line is 0. But RTS doesn't change at all.

What am I missing?

board.dts

&uart1 {
	uart-has-rtscts;
	pinctrl-names = "default", "sleep";
	pinctrl-0 = <&uart1_pins_a>;
	pinctrl-1 = <&uart1_pins_b>;
	status = "okay";
};

sun8iw20p1.dtsi

code		uart1: uart@2500400 {
			compatible = "allwinner,sun8i-uart";
			device_type = "uart1";
			reg = <0x0 0x02500400 0x0 0x400>;
			interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
			sunxi,uart-fifosize = <256>;
			clocks = <&ccu CLK_BUS_UART1>;
			clock-names = "uart1";
			resets = <&ccu RST_BUS_UART1>;
			uart1_port = <1>;
			uart1_type = <4>;
			status = "okay";_text

code

#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

static struct termios oldterminfo;

void closeserial(int fd)
{
    tcsetattr(fd, TCSANOW, &oldterminfo);
    if (close(fd) < 0)
        perror("closeserial()");
}

int openserial(char *devicename)
{
    int fd;
    struct termios attr;

    if ((fd = open(devicename, O_RDWR)) == -1) {
        perror("openserial(): open()");
        return 0;
    }
    if (tcgetattr(fd, &oldterminfo) == -1) {
        perror("openserial(): tcgetattr()");
        return 0;
    }
    attr = oldterminfo;
    attr.c_cflag |= B19200 | CRTSCTS | CLOCAL | CS7 | CSTOPB | PARENB;
    attr.c_cflag &=  ~PARODD;
    //attr.c_cflag &= ~CRTSCTS;
    attr.c_oflag = 0;
    if (tcflush(fd, TCIOFLUSH) == -1) {
        perror("openserial(): tcflush()");
        return 0;
    }
    if (tcsetattr(fd, TCSANOW, &attr) == -1) {
        perror("initserial(): tcsetattr()");
        return 0;
    }
    return fd;
}

int setRTS(int fd, int level)
{
    int status;

    if (ioctl(fd, TIOCMGET, &status) == -1) {
        perror("setRTS(): TIOCMGET");
        return 0;
    }
    if (level)
        status |= TIOCM_RTS;
    else
        status &= ~TIOCM_RTS;
    if (ioctl(fd, TIOCMSET, &status) == -1) {
        perror("setRTS(): TIOCMSET");
        return 0;
    }
    return 1;
}


int main()
{
  unsigned char msg1[] = { 'G','0','1', '\r', '\n' };
  unsigned char msg0[] = { 'G','0','0', '\r', '\n' };
    int fd;
    char *serialdev = "/dev/ttyS1";

    fd = openserial(serialdev);
    if (!fd) {
        fprintf(stderr, "Error while initializing %s.\n", serialdev);
        return 1;
    }

    setRTS(fd, 0);
    write(fd, &msg1, sizeof(msg1));
    printf("1\r\n");
    sleep(1);       /* pause 1 second */
    setRTS(fd, 1);
    write(fd, &msg0, sizeof(msg0));
    printf("0\r\n");
    sleep(1);       /* pause 1 second */


    closeserial(fd);
    return 0;
}

[KunYi]

@emresensoy

check device tree first, check uart1_pins_a with RTS/CTS pin control

pinctrl-0 = <&uart1_pins_a>;

[emresensoy]

此回复已被删除！

[emresensoy]

@kunyi
Thank you for your answer,
I am attaching board.dts file's relevant section, there is PG6 to PG9, Rx Tx RTS and CTS lines,

	uart1_pins_a: uart1_pins@0 {  /* For EVB1 board */
		pins = "PG6", "PG7", "PG8", "PG9";
		function = "uart1";
		drive-strength = <10>;
		bias-pull-up;
	};

	uart1_pins_b: uart1_pins {  /* For EVB1 board */
		pins = "PG6", "PG7", "PG8", "PG9";
		function = "gpio_in";
	};

[KunYi]

Okay, Maybe you can try the below code

#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/serial.h>
#include <string.h>

int main(int argc, char *argv[]) {
    // Open serial port ttyS1
    const char *device = "/dev/ttyS1";
    int fd = open(device, O_RDWR | O_NOCTTY);
    
    if (fd < 0) {
        perror("Error opening serial port");
        return -1;
    }

    // Get the current serial port settings
    struct termios tty;
    if (tcgetattr(fd, &tty) < 0) {
        perror("Error getting port attributes");
        close(fd);
        return -1;
    }

    // Configure the serial port settings
    // Clear all settings first
    tty.c_cflag = 0;
    tty.c_iflag = 0;
    
    // Enable receiver, ignore modem control lines
    tty.c_cflag |= CREAD | CLOCAL;
    
    // Enable hardware flow control (RTS/CTS)
    tty.c_cflag |= CRTSCTS;
    
    // Set baud rate to 19200
    cfsetispeed(&tty, B19200);
    cfsetospeed(&tty, B19200);
    
    // Set 7 bits per byte
    tty.c_cflag |= CS7;
    
    // Enable even parity bit,  without PARODD
    tty.c_cflag |= PARENB;
    
    // Set 2 stop bits
    tty.c_cflag |= CSTOPB;
    
    // Apply the new settings
    if (tcsetattr(fd, TCSANOW, &tty) < 0) {
        perror("Error setting port attributes");
        close(fd);
        return -1;
    }

    printf("Serial port configured successfully\n");
    printf("Port configuration:\n");
    printf("- Device: %s\n", device);
    printf("- Baud rate: 19200\n");
    printf("- Data bits: 7\n");
    printf("- Parity: Even\n");
    printf("- Stop bits: 2\n");
    printf("- Flow control: RTS/CTS\n");

    // Test string to send
    const char *test_string = "Hello! This is UART1\n";
    ssize_t bytes_written = write(fd, test_string, strlen(test_string));
    
    if (bytes_written < 0) {
        perror("Error writing to serial port");
    } else {
        printf("\nSent %zd bytes: %s", bytes_written, test_string);
    }

    // Keep the port open briefly to ensure transmission
    sleep(1);

    // Close the serial port
    close(fd);
    return 0;
}

[emresensoy]

This is the output of your code, when the flow control enabled, there is no UART1 output even if CTS=0,

=============================================================

if I disable CRTSCTS flow control, it pushes data to UART1 but no RTS

[emresensoy]

SOLVED,

I used a device to sniff UART between F133 and slave device,
Its RTS CTS line corrupted, so I removed it and everything ok now,

thanks for your kind help