NanoPC-T4 UART Basics

[tmountain]

Hi,

 

I'm new to the SoC / Armbian world, and I'm trying to connect to my NanoPC-T4 via UART (Armbian 20.11.7 Focal with Linux 5.9.14-rockchip64). I'm using an ADAFRUIT Industries 954 USB-to-TTL serial cable. The NanoPC-T4 pin spec indicates 

SPI1_TXD/UART4_TX(3V) as pin 19, GND as pin 20, and SPI1_RXD/UART4_RX(3V) as pin 21. I have hooked up my ADAFRUIT accordingly with the white receptacle (RX) to pin 19, the black receptacle (GND) to pin 20, and the green receptacle (TX) to pin 21.

 

The full NanoPC-T4 pin spec is here: http://wiki.friendlyarm.com/wiki/index.php/NanoPC-T4.

 

The kernel command line is as follows:

 

[    0.000000] Kernel command line: root=UUID=cb1cdae1-67a0-4938-850e-0ca79ecd821c rootwait rootfstype=ext4 bootsplash.bootfile=bootsplash.armbian console=ttyS0,1500000 console=ttyS2,1500000 console=tty1 consoleblank=0 loglevel=1 ubootpart=7fa9e296-01 usb-storage.quirks=0x2537:0x1066:u,0x2537:0x1068:u   cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory swapaccount=1

 

Dmesg says the following regarding serial:

 

[    2.776290] printk: console [ttyS0] disabled

[    2.776366] ff180000.serial: ttyS0 at MMIO 0xff180000 (irq = 39, base_baud = 1500000) is a 16550A

[    2.776554] printk: console [ttyS0] enabled

[    2.776724] serial serial0: tty port ttyS0 registered

[    2.777537] ff1a0000.serial: ttyS2 at MMIO 0xff1a0000 (irq = 40, base_baud = 1500000) is a 16550A

[    2.778797] Serial: AMBA driver

 

I've connected the USB end of the cable to my raspberry pi to attempt to connect via screen:

 

root@retropie:/home/pi# screen /dev/ttyUSB0 1500000

 

root@retropie:/home/pi# screen /dev/ttyUSB0 115200

 

Neither of those gives a login prompt. I have been able to make this work in the opposite direction (connecting from NanoPC-T4 to the serial of the Pi). Any suggestions would be appreciated. Thanks!

Edited January 17, 2021 by tmountain

[usual user]

1 hour ago, tmountain said:

The full NanoPC-T4 pin spec is here: http://wiki.friendlyarm.com/wiki/index.php/NanoPC-T4.

Restudy your referenced spec. The default serial console is located at "Debug UART".

[tmountain]

Ah, thank you for this. Got it working!