VC++/CLI and Serial Port

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My code is working perfectly fine except I don't believe it is optimal and is going work reliably for fast response or handle significan delays.

Is there a better way of doing this? I would like it to just only wait for the arrival of the first 8 byte data on the buffer and read and continue on to the next task?

C++

Sleep (2000);                           //delay
serialPort1->;DiscardInBuffer();        //clear serial port in buffer
serialPort1->;DiscardOutBuffer();       //clear serial port out buffer

auto Power = gcnew array<System::Byte> {0x52, 0x0C, 0x01, 0x00, 0x00};
serialPort1->Write(Power, 0, Power->Length);


Sleep(500);
auto Power1 = gcnew array<System::Byte> {0x00, 0x00, 0x00, 0x00, 0x00};
serialPort1->Read(Power1, 0, Power1->;Length);

String^ str2 = String::Format("{0:X2} {1:X2} {2:X2} {3:X2} {4:X2}", Power1[0], Power1[1], Power1[2], Power1[3], Power1[4]);

String^ str3 = String::Format("{2:N0}", Power1[0], Power1[1]);

richTextBox1-&gt;Text += "Power Level     ->   ";
richTextBox1-&gt;Text += str3 + "Watts" "\r\n";

Posted 6-Aug-14 9:27am

Member 10790434

Updated 7-Aug-14 9:33am

CPallini

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Philippe Mori 7-Aug-14 20:32pm

What is the purpose of the initial delay (2000 ms)?

Philippe Mori 7-Aug-14 20:36pm

The easy way to do background processing is touse a background worker. For receiving, you also dont really need a wait but an appropriate timeout.

Member 10790434 8-Aug-14 15:19pm

Philippe,
There isn't a need for the initial timeout but on the subsequent steps it does need it the way it is written now. How and where in code to put timeouts? Thanks.

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KarstenK · Answer 1 · 2014-08-07T05:44:00

Solution 1

A better way is to user overlapped communication, because sleep blocks the thread.

In this articel: Serial Communication in Windows is it well explained.

It makes also sense to create a write and a read thread for the port.

An article with background information but in C#.

Posted 7-Aug-14 5:44am

KarstenK

CPallini · Answer 2 · 2014-08-07T09:43:00

Solution 2

You should get rid of all the Sleep calls and work asynchronously with the serial port: write your data and then and then handle the DataReceived event, gently provided by the SerialPort class (see SerialPort::DataReceived Event[^]).

Posted 7-Aug-14 9:43am

CPallini

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Member 10790434 7-Aug-14 16:28pm

CPallini/KarstenK, thank you.

I am using a single button click to write to and read from the serial port 8 data arrays sequentially in the same format as above for the remaining 7. The issue is if I remove the delays, I get bad data because there is not enough time for the arriving response.

DataReceivedHandler is definitely the way to go but I am not sure how I can get button_click and DataReceivedHandler to work together or if that is even possible?