ESP-AT and linux kernel communication

[reofit77]

Hello

I'm trying for send at-commands from linux kernel and reading the response over uart, but when I read from the device after writing to it, I get some random characters which may change depending on the execution. These characters are different from the expected response.
When I use the Arduino monitor, I can send at-commands and get the response as expected.
Also, when I have already used the Arduino monitor atleast once, I get the expected response with "busy p...". So I taught the problem was because I did not set the configuration for the tty device, but when I set the tty configurations, the linux kernel freezes.

This is my code below with some of the configurations I have tried to set.

Code: [Select all] [Expand/Collapse]

1.  char response_buf[64];
2.  
3.     struct file *esp_device_file = filp_open(esp_device, O_RDWR | O_NONBLOCK, 0);
4.     struct tty_struct *tty = (struct tty_struct *) esp_device_file->private_data;
5.  
6.     // struct ktermios n_termios;
7.     // down_read(&tty->termios_rwsem);
8.     // n_termios = tty->termios;
9.     // up_read(&tty->termios_rwsem);
10.     // tty_termios_encode_baud_rate(&n_termios, B115200, B115200);
11.     // tty_set_termios(tty, &n_termios);
12.  
13.     // tty_encode_baud_rate(tty, B115200, B115200);
14.     // speed_t baud = tty_get_baud_rate(tty);
15.  
16.     // tty_write_message(tty, rawtp_command);
17.     tty->ops->write(tty, rawtp_command, sizeof(rawtp_command));
18.  
19.     if(kernel_write(esp_device_file, rawtp_command, sizeof(rawtp_command), 0) > 0)
20.     {
21.         printk(KERN_INFO "***** Writing done successfully *****");
22.         kernel_read(esp_device_file, response_buf, sizeof(response_buf), 0);
23.  
24.         printk(KERN_INFO "***** Reading done successfully *****");
25.  
26.     }
27.  
28.     printk(KERN_INFO "***** File closed successfully *****");

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Any response is welcomed.
Thanks.

[ESP_Sun]

Hi,

I'm guessing this may be due to different UART level pull-ups and pull-downs for different MCUs. Maybe you can check from here?