Serial Console for the Rock64

[MarkHaysHarris777]

Greetings;

The purpose of writing this tutorial is to provide guidance for using a serial ttl to usb bridge cable to connect the Rock64's uart (on the PI-2 bus) to a usb port on your PC or Mac, for the purpose of monitoring the boot-up process and logon from a serial terminal.

Please see this reference link:

It is important to select a bridge cable that supports at least 1.5M baud (default for Rock64 serial uart) and which has 3v3 logic ( measure the votage on the Tx pin must be no more than 3v3 !).

Most 3v3 cp2102, pl2303hx, and some ch340g chips will work.

The uart pins on the Rock64 PI-2 bus are in the same places as the RPi -- pin(6 gnd), pin(8 Tx), and pin(10 Rx).   The Tx pin of the ttl adapter goes to the Rx pin of the Rock64(10) Tx-->Rx;  and the Rx pin of the ttl adapter goes to the Tx pin of the Rock64(8) Rx-->Tx.  Connect the ground(s) together;  it is important that the ground leads are not left open.  DO NOT connect the red voltage wires anywhere.

The usb end of the ttl to usb bridge cable plugs into a usb port on your PC or Mac. Terminal software (like minicom, screen, cu, or putty) is then used on the PC or Mac to connect to the appropriate usb device.  The baud terminal settings are 1500000 8n1. 

With the serial console running you can monitor the boot-up messages on the Rock64 (or other SBC) and get diagnostic clues (if things aren't working properly) or in the case of certain procedures (like writing to the eMMC on the Rock64) you can interrupt the uboot three second timer with the serial console.

Please check out this link too, for using the PineA64 (or other SBC) as a serial console monitor: