Serial Debug

Preparing a USB Serial adaptor

Lots of adaptors for converting USB to serial port are available for
sale in the online stores. And according to the different chips, these
adaptors can be divided into the following types:

[CP2104]

PL2303

CH340

*** Note：The default baud rate of ROC-RK3308-CC is 1500000. Some usb
to serial converter, it's baud rate can't reach 1500000，even
different series of the same chip may also have differences，so be
sure to support before purchasing adaptor. Here, the official
recommended adapter for the CP2104 chip. ***

Connecting to the Debug Serial Port

ROC-RK3308-CC debug serial port default baud rate is 1500000, and it
is recommended to use the official

CP2104 USB-to-UART serial port converter

, the connection method is as follows:

GND line: ground line of serial port, connect to GND needle of
demoboard

TXD line : output line of serial port, connect to TX needle of
demoboard

RXD line: input line of serial port, connect to RX needle of demoboard

The hardware connection is as below:


Serial Parameters

ROC-RK3328-CC uses the following serial parameters:

Baud rate: 1500000

Data bits: 8

Stop bit: 1

Parity: None

Flow control: None

Serial Debugging in Windows

Install drive

Download and install drive:

CP2104

After installing the CP210X driver which is from the official website
on a Windows system, use a tool such as PUTTY or SecureCRT to set the
serial port baud rate to 1500000 . If the settings are not available
or are invalid, you can download the old version

driver

.

When inserting the adapter, the system will prompt to discover new
hardware. You can find the corresponding COM port in the device
manager.

Install tools

As for Windows, the putty or SecureCRT are usually used. Putty is a
open source software program. This paper mainly introduces how to use
putty. And the method for using SecureCRT is similar to that of putty.

Comimg here to

Download putty

, it is recommended to download "putty.zip", because it contains other
useful tools.

Unzipping it and run PUTTY.exe,  choosing "Connection type" of Serial
（serial port）, set "Serial line" as a COM port that can be seen from
device manager, and set "Speed"（baud rate）as 1500000, then press
"Open":


Serial Debugging in Linux

There could be multiple choices on Ubuntu:

picocom

minicom

kermit

It is quite easy to use picocom, and we will introduce how to use
picocom below. The method to use other software is similar.

Install picocom

   sudo apt-get install picocom

After connecting the serial cable, look at the serial device file. for
example:

   ls /dev/ttyUSB*
   /dev/ttyUSB0

Running picocom

   picocom -b 1500000 /dev/ttyUSB0
   picocom v1.7

   port is        : /dev/ttyUSB0
   flowcontrol    : none
   baudrate is    : 1500000
   parity is      : none
   databits are   : 8
   escape is      : C-a
   local echo is  : no
   noinit is      : no
   noreset is     : no
   nolock is      : no
   send_cmd is    : sz -vv
   receive_cmd is : rz -vv
   imap is        : 
   omap is        : 
   emap is        : crcrlf,delbs,

   Terminal ready

As for the above prompts, "Ctrl-a" is the escape key, press "Ctrl-a"
"Ctrl-q" to exit the terminal. Besides, "Ctrl-q" , there are also
several commonly used control commands:

Ctrl-u : raise baud rate

Ctrl-d : reduce baud rate

Ctrl-f :  switch flow control setting（hardware flow control RTS/CTS,
software flow control XON/XOFF,  none）

Ctrl-y : switch parity check （ even, odd, none）

Ctrl-b : switch data bits （5, 6, 7, 8）

Ctrl-c : switch local-echo

Ctrl-v : show parameters and status of current serial port