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+<pagebreak>
+====== RS-232 on Linux ======
+Example based on Ubuntu
+Prerequisites: minicom terminal emulator
+If the program is missing, install it with: //sudo apt-get install minicom//
+Connect the microcontroller to a USB-COM converter and check if it was detected by the system: //dmesg | grep tty//
+the result could look like this:
+  [    0.000000] console [tty0] enabled
+  [ 3823.820524] usb 5-1: pl2303 converter now attached to ttyUSB0
+  [ 3937.382589] usb 5-2: FTDI USB Serial Device converter now attached to ttyUSB1
+  [ 4152.680434] pl2303 ttyUSB0: pl2303 converter now disconnected from ttyUSB0
+  [ 4159.873377] ftdi_sio ttyUSB1: FTDI USB Serial Device converter now disconnected from ttyUSB1
+  [ 4164.285887] usb 5-2: FTDI USB Serial Device converter now attached to ttyUSB0
+  [ 4215.343098] usb 5-1: pl2303 converter now attached to ttyUSB1
+  [ 4633.056395] pl2303 ttyUSB1: pl2303 converter now disconnected from ttyUSB1
+  [ 4659.016240] usb 5-1: pl2303 converter now attached to ttyUSB1
+From this output you need to determine which port is assigned to the USB converter.
+When the example code is loaded into the microcontroller, open minicom (preferably with root permissions):
+//sudo minicom -s//
+{{:examples:communication:minicom_welcome.png?550|}}
+First you need to configure the connection:
+To set the port, press key A and set the connection, for example: ///dev/ttyUSB1//
+and the port parameters Bps/Par/Bits, for example: //115200 8N1//
+Press ESC to exit.
+{{:examples:communication:minicom_port_conf.png?550|}}
+After selecting //Exit//, minicom initializes the port connection.
+The microcontroller must be connected to the computer's USB converter using a cross cable (also known as a 0-modem cable).
+The program below responds to every symbol received on the UART port with a greeting and toggles the LED on the board.
+{{:examples:communication:minicom_action.png?550|}}
+If you want to see your own keypresses, enable local echo: //CTRL+A E//
+<code c>
+#include <homelab/usart.h>
+#include <homelab/delay.h>
+#include <homelab/pin.h>
+usart port = USART(0);      //COM connector
+pin led = PIN(B, 7);        //red LED on controller board
+int main (void)
+{
+    char c;
+    pin_setup_output(led);  //set led as output
+    usart_init_async(port,  //USART setup
+        USART_DATABITS_8,
+        USART_STOPBITS_ONE,
+        USART_PARITY_NONE,
+        USART_BAUDRATE_ASYNC(115200));
+    while (1)   //infinite loop
+    {
+          //if char is sent to controller, read it into c
+        if (usart_try_read_char(port, &c))
+        {
+            //invert LED
+            pin_toggle(led);
+            // Write some greetings
+            usart_send_string(port, "Tere volts!\r\n");
+        }
+    }
+}
+</code>

en/examples/communication/rs232/linux.txt · Last modified: 2026/02/19 11:30 by 127.0.0.1