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Matlab RS232 COM port can not read data!

1 次查看（过去 30 天）
michael woodcock
michael woodcock 2019-7-18
关闭： michael woodcock 2019-7-18
Hey guys I'm trying to get the basics down for matlab serial communication but I'm having trouble. Here is where I'm at with the serial hardware, without involving matlab:
  1. arduino communicating to TTL/rs232 usb converter
  2. confirmed the above setup works. opened termite terminal viewer and used the arduion terminal monitor and I was easily able to send data from com port 9 to 8
  3. also passed the "echo test"
Where I'm having trouble is reading the data from the serial device in MATLAB. I've tried to many things, over and over again. I just started from scratch, here's the matlab code:
clear
clc
%Inializing com port
%this seems to initialize serial: s=serial('COM8','BaudRate',9600,'Terminator','CR')
%serial='COM8'
s=serial('COM8')
fopen(s)
% fprintf(serial,'*IDN') this would just open com 8 to print stuff too
%&fscanf(s) reads data from serial port
%serial port opject in this case: fopen(serial-COM8)
%serial name: Serial-COM8
%Port Name: COM8
fprintf(s,['ch:%d scale:%d'],[1 20e-3],'sync')
Here's the arduino code:
/*
* Hello World!
*
* This is the Hello World! for Arduino.
* It shows how to send data to the computer
*/
void setup() // run once, when the sketch starts
{
Serial.begin(9600); // set up Serial library at 9600 bps
}
void loop() // run over and over again
{
Serial.println("Hello world!"); // prints hello with ending line break
delay(1000);
}
I should be able to read "Hello world" from the arduino on COM8, but I simply can't.
OK guys I found an example code here:
https://www.mathworks.com/matlabcentral/fileexchange/12526-matlab-serial-code-example
and it works. I'm suprized at the format. Do We really have to open and close the port,? Also I was kindof unaware of teh query command,
my last question is how do we send data to serial port?
Here's the example code I found that worked to read it:
% Create a serial port object.
obj1 = instrfind('Type', 'serial', 'Port', 'COM3', 'Tag', '');
% Create the serial port object if it does not exist
% otherwise use the object that was found.
if isempty(obj1)
obj1 = serial('COM8');
else
fclose(obj1);
obj1 = obj1(1)
end
% Connect to instrument object, obj1.
fopen(obj1);
% Communicating with instrument object, obj1.
data1 = query(obj1, '*IDN?');
% Disconnect from instrument object, obj1.
fclose(obj1);
% Clean up all objects.
delete(obj1);
fprintf(data1)

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