Uart2 Serial Console¶

Instructions work for the MitySOM-AM62x, MitySOM-AM62a, and MitySOM-AM62p

Prerequisites¶

• USB serial cable with broken out pins: https://www.digikey.com/en/products/detail/ftdi-future-technology-devices-international-ltd/TTL-232R-RPI/4382044
• A host system with a USB connection. (Windows or Linux PC)
• Run through setting up a serial console.

Step 1: Board Setup:¶

• Connect the USB serial cable with broken out pins to the following ports on the "P3 Expansion"
  
  • Pin 24 GND (Black Cable)
  • Pin 26 UART2_RXD (Green Cable)
  • Pin 28 UART2_TXD (White Cable)
• Another angle
  

Step 2: Open the new Serial Console¶

• Check which usb the serial cable connected to
  

  $ sudo dmesg
  [84700.175119] pl2303 3-2.4.4.3.1:1.0: pl2303 converter detected
  [84700.203234] usb 3-2.4.4.3.1: pl2303 converter now attached to ttyUSB2
  

• Using your preferred serial console (putty, microcom, teraterm) configure the serial port found in the previous step as: 3000000 baud rate.
• launch the console

Step 3: Update the Code in Linux-ti Project¶

• In arch/arm64/boot/dts/ti/k3-am62x-mitysom-devkit.dts
  

  AM62X_IOPAD(0x0198, PIN_INPUT_PULLDOWN, 7) /* (A19) MCASP0_AXR2.GPIO1_8 */
  AM62X_IOPAD(0x01b4, PIN_INPUT_PULLDOWN, 7) /* (A13) SPI0_CS0.GPIO1_15 */
  - AM62X_IOPAD(0x01d0, PIN_INPUT_PULLDOWN, 7) /* (A15) UART0_CTSn.GPIO1_22 */
  - AM62X_IOPAD(0x01d4, PIN_INPUT_PULLDOWN, 7) /* (B15) UART0_RTSn.GPIO1_23 */
  AM62X_IOPAD(0x01d8, PIN_INPUT_PULLDOWN, 7) /* (C15) MCAN0_TX.GPIO1_24 */
  AM62X_IOPAD(0x01dc, PIN_INPUT_PULLDOWN, 7) /* (E15) MCAN0_RX.GPIO1_25 */
  

  
  

          AM62X_IOPAD(0x01f0, PIN_INPUT_PULLDOWN, 7) /* (A18) EXT_REFCLK1.GPIO1_30 */
          /* (D16) EXTINTn.GPIO1_31 Used on SOM for PMIC interrupt */
      >;
   };
  + 
  +   main_uart2_pins: main-uart2-pins {
  +   pinctrl-single,pins = <
  +       AM62X_IOPAD(0x1d4, PIN_OUTPUT, 3) /* (B15) UART2_TXD Console */
  +       AM62X_IOPAD(0x1d0, PIN_INPUT, 3) /* (A15) UART2_RXD Console */
  +   >;
  +   };
  + };
  + 
  + &main_uart2 {
  +     pinctrl-names = "default";
  +     pinctrl-0 = <&main_uart2_pins>;
  +     status = "okay";
  + };
  

  
  

   / {
  +    aliases {
  +            serial10 = &main_uart2;
  +    };
  
      vcc_12v: vcc_12v {
  

  
  Note: You will have to update AM62X_IOPAD for your respective SOM

Step 4: Check Uart2 Functionality¶

• Build your changes and copy them to your mmc device (ex. SD card)
• Boot to the linux kernel and run the following command
  

  root@mitysom-am62x:~# dmesg | grep serial
  [    1.480682] 2800000.serial: ttyS2 at MMIO 0x2800000 (irq = 238, base_baud = 3000000) is a 8250
  [    1.511687] 2820000.serial: ttyS10 at MMIO 0x2820000 (irq = 240, base_baud = 3000000) is a 8250
  [    3.288480] systemd[1]: Created slice Slice /system/serial-getty.
  

  • As you can see "ttyS10" is now setup and ready for serial communication

Step 5: Run Microcom Command¶

• Create a serial connection from uart2 to your local computer
  

  root@mitysom-am62x:~# microcom -s 3000000 /dev/ttyS10
  
  

  • Try typing "Hello World" and you should see it print out on the new serial console you opened in step 2.

Summary¶

This wiki page has demonstrated the following:

• Configuring the uart2 serial port.
• Creating a serial connections between the uart2 serial port and the connected local device.