🚀 go-pugleaf

I like to thank everyone for helping me.

I hope the code snippet did not confuse anyone, and I know I might not be
doing things right, but I am trying to correct my mistakes.

I don't use CheckCommStatus() anywhere in my snippet?

> Your use of CheckCommStatus() to poll the serial port status could be
> slowing the code down.  If you get rid of it entirely and just let the
> overlapped I/O do the work for you, you'll probably notice that your
unit's
> responses come through a lot faster.  You know that the unit should be
> sending a byte back to you, so just perform an overlapped reading
> immediately after you finish writing, and you will still be able to detect
> when the reading has completed.

> Gambit

Let me explain, a little more to see if my problem becomes a whole lot
clearer for everyone.
I have developed a unit that talks with a software application using
commport 1 or COM1.
The embeded unit and pc software is communicating @ 9600 baud.  The pc
software is the
master and the embeded unit is a slave.  I poll the embeded unit and it
responds ( < 1ms) for
all intend and purposes.  I tested the respond time of the embeded unit
using Hyperterminal and
it never fails ( < 1ms) you can't even time it, if all your using is
Hyperterminal, just see that it always
respond immediately.  Now, if Hyperterminal is using the same baud rate and
same settings as my
application, I expect my application to behave the same way.

Yet what I find, is that in the snippet I sent if I write a little more test
code, where I increment a counter
to see how many attempts it takes to recieve the information coming from the
embeded unit, I find that
it sometimes takes more than 3 tries, sometimes more than 10 tries, before
the unit comes out of the loop.
The question is why?  The information should be there almost instantly.
This is my calculations,

9600 baud = 104.16 us per bit, if I am recieving just one byte coming back,
104.16 uS x 8bits = 833.28 uS

in my code snippet, I use GetTickCount to start a timer of the number of
bytes expected and I go ahead and multiply it by 2, so at to give it even
more time.  So if I am doing things correctly, I should have 833.28uS x 2
1.66Sec approximately double the time it would take for that byte to
actually get Windows to pick up the byte and have it ready for me to read
it?

I go a step further and give the application an extra three times to try and
it still fails?

I don't understand why? Everything tells me the byte should be there and
maybe it is, but definetly I am doing something terribly wrong in my Read
snippet, because I am not getting that byte????

Can you guys look at my snippet and see what I am doing wrong, I have no
idea, I have tried everything I know?

Thank you,
Neil P.