Subj : Re: Win32 RS-232 help
To   : borland.public.cpp.borlandcpp
From : Jeff Baker
Date : Fri Apr 30 2004 04:22 am

Well, I'm an idiot! I found the problem. It's in my data types. The
send_stream array was initialized as an INT data type (16-bit) and so was
the received array. Since I am only allowed to send/receive 8-bit data types
the whole process was screwed up from the beginning. I imagine that the
device was trying to return a NAK condition but it was being stored in an
incorrect format so I couldn't correctly identify the returned data. That
also explains why the data was exactly the same every time. It was telling
me that a transmission error or command error was received I just couldn't
interpret it correctly. Anyway, here is the source code in it's working
form. I will be using your idea
(ReadFile(Com.handle,&Com.received[totalread],to_read,&read,NULL)) because
the device will accept many commands and I don't know exactly how long the
return stream will be for any of rest of them.

void ComRoutine()
{
   unsigned char x,send_stream[]={4,0,0,0,4,0};
   DWORD to_write = 6;
   DWORD written = 0;
   DWORD to_read = 28;
   DWORD read = 0;
   gotoxy(1,8);
   textcolor(LIGHTGREEN);
   if (! WriteFile(Com.handle,send_stream,to_write,&written,NULL))
   {
      textcolor(LIGHTRED);
      cprintf("Unable to write to %s!\r\n",Com.number);
   }
else if (to_write != written)
   {
      textcolor(LIGHTRED);
      cprintf("Unable to write entire stream to %s
(TIME_OUT)!\r\n",Com.number);
   }
else cprintf("%s was written to successfully.\r\n",Com.number);
if (! ReadFile(Com.handle,&Com.received[read],to_read,&read,NULL))
   {
      gotoxy(1,9);
      textcolor(LIGHTRED);
      cprintf("Unable to read from %s!\r\n",Com.number);
   }
else if (to_read != read)
   {
      gotoxy(1,9);
      textcolor(LIGHTRED);
      cprintf("Received %d bytes from %s, we expected %d
(TIME_OUT)!\r\n",read,Com.number,to_read);
   }
else
   {
      gotoxy(1,10);
      cprintf("REC: ");
      for(x = 0; x < (unsigned char)read; x++)
      {
         cprintf("%i ",Com.received[x]);
         clreol();
      }
   }
}

Thanks again Bob and anyone else that was trying to get me an answer. I'll
keep everyone up to date on my project. Btw, this software is for a digital
multimeter (available from radio-shack) that has an RS-232 port on it. I
decided to write my own software for it so I could learn to program in a
Win32 environment. It will eventually be a GUI and not console and I will
probably give it to anyone who wants a copy when it's done.

Best Regards,
- Jeff

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