a for loop not loop not looping

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Hi All,

Asked a stupid question earlier about string arrays and found the answer myself after typing the question (thanks also to Manfred R. Bilhy) so I hoping to do this again. I have to send a group of strings from the serial port to a waiting board.
I have comms to the board I can sent and recieve data as well it is just I can't get it to upload all the data:

C#

for (int b = 0; b <= 5; b++)
         {
             Command = CommandA[1] + '\n' + '\r';
             rtbIncoming.SelectionStart = rtbIncoming.Text.Length;
             rtbIncoming.ScrollToCaret();
             Length_Command = Command.Length;
             for (int Counter = 0; Counter <= Length_Command + 1; Counter++)
             {
                 if (Counter == Command.Length)
                 {
                     return;
                 }
                 Command_Sent = Command.Substring(Counter, 1);
                 myComPort.Write(Command_Sent);

             }

That is the for loop thats being the problem the method of writing out works (bit of a kludge I worked out ages ago.
Using a Serial Port Monitor I can tell it replies to my command with 0D or Carriage Return, the text OK and an OD and a > prompt.
Anybody Any Ideas?
Glenn

Posted 9-Dec-11 2:42am

glennPattonWork3

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Comments

Ed Nutting 9-Dec-11 8:56am

Your code seems self defaeting - you run the second loop from 0 to Command Length + 1 yet in the loop you have an if Counter == Length_Command. Meaning the loop only really runs from 0 to Command.Length : did you mean this?

Jephunneh Malazarte 9-Dec-11 9:19am

what is the possible value for your CommandA[1]?

glennPattonWork3 9-Dec-11 9:32am

to Edward Nutting, That works like I said its a kludge to get around the awkward way this microcontrollers on board UART runs, if I didn't send individual characters the board ignors it.
to Jephunneh Malaztre CommandA[1] contains "SLD:0002:4181246867"

Timberbird 9-Dec-11 9:42am

What is the outer (for (int b = 0; b <= 5; b++)) loop for? return will exit this method as soon as you reach Length_Command. Should Command value be changed inside that second loop?

glennPattonWork3 9-Dec-11 9:48am

Thanks, that looks like it, a quick test shows it is getting past if I change the return to a break!!!

Timberbird 9-Dec-11 9:52am

Well, it should :). Breaks only interrupt current cycle, while return forces your program to leave the function

glennPattonWork3 9-Dec-11 10:35am

I miss ANSI C and DOS :) any good ideas for waiting for an OK from the board.

Addy Tas 9-Dec-11 17:46pm

Add another thread for reading and validating the read data, then if you got what you want set a event; the other side (writer) needs to wait for the event before it does something.

To avoid any other issues; please make your design to also wait for an exit event and use a timeout to verify the current state / resend the command.

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glennPattonWork3 · Answer 1 · 2011-12-12T02:14:00

Solution 3

We use Advanced Serial Port Monitor by AGG its quite good. I added the dreaded Thread.Sleep and got an odd reaction. I hate to say it but I think the board is not playing nicely!

Posted 12-Dec-11 2:14am

glennPattonWork3

Romain TAILLANDIER · Answer 2 · 2011-12-10T13:34:00

If your board wait an only character, may be this loop is too fast, so your microcontroller program considere it a many chars. Have you tried to add a sleep between successive writes ?

Addy Tas, suggest to read in another thread, i agree. But the mono-threaded microcontroller probably do not need that. I have the intuition you can simply block while getting your replies.
You can easily wait using a loop like this one :

C#

while(myComPort.BytesToRead ==0) 
   ;

Which is a dangerous inifnite loop if nothing happend, can be worked around with something like this (i don't have the code here, but it should be something like that)

C#

public int WaitForData(int NbDataToWait, int Timeout)
{
    int timeWaited = 0;
    int timeToWait = 1; // 1 ms
    while (timeWaited < Timeout && MyCompPort.BytesToRead < NbDataToWait)
    {
        timeWaited += timeToWait ;
        System.Threading.Thread.Sleep(timeToWait );
    }
    return timeWaited;
}