Serial RS232 port protocol

Which Khadas SBC do you use?


Which system do you use? Android, Ubuntu, OOWOW or others?


Which version of system do you use? Khadas official images, self built images, or others?


Please describe your issue below:


I would like the VIM3 to control 1) a servo driver and communicate to 2) a Laser Controller via the Linux_RX and Linux_TX pins that use the 3.3V RS232 port protocol.

I would like to know if it is possible to use the same pins 18 and 19 to control 2 drivers/controllers using the RS232 serial protocol.

Or is there a way for two controllers to be on the same bus or same pins?

Thank you,

Hi PIN18 & PIN19 are used as the debug console by default, you can’t use it directly, you have to do some modifications. You need to remove console=${uart_tty},115200n8 in /boot/boot.ini

diff --git a/config/bootscripts/aml_boot.ini b/config/bootscripts/aml_boot.ini
index 73d3d67c..4e7b914b 100644
--- a/boot.ini
+++ b/boot.ini
@@ -240,7 +240,7 @@ for dev in ${devs}; do
                                                        setenv tty_console "console=tty0";
-                                               setenv condev "console=${uart_tty},115200n8 ${tty_console} no_console_suspend consoleblank=0";
+                                               setenv condev "${tty_console} no_console_suspend consoleblank=0";
                                                # Device Tree Overlays
                                                if test "X${overlays}" != "X"; then

Why not to use the PIN15 & PIN16? Or you must need 2 UARTs ?

Hi, thank you for the response.

  1. I have remapped pins 15 and 16 as GPIO pins. Are pins 15 and 16 UART pins, what is the voltage and protocol that it follows?

  2. One of the device I want control has only RS232 port protocol 3.3V and the other is a serial communication. Is there a way to have multiple devices on the same RS232 pins 18 and 19?

  3. I am using an I2C port expander on pin 22, 23 and 25, so I believe that interferes with the SPI pins on the VIM3, please correct me if I am wrong?

Same as PIN18 & PIN19.

Have you tested? Any issues?

VIM3 SPI pins are as below: