There are several ways to directly address the ports. Depends on the OS you
are using. If you have a copy of one of my old books, DOS 5: A Developer's
Guide (or DOS 6: A Developer's Guide) you can find the DOS variations in
there.

For Windows 95 and NT, the serial port is pretty easy. Open the COM Port
using CreateFile(). Then you can use GetCommModemStatus() to read the
CTS/DSR bits (but not RX). You can set the outputs (RTS/DTR/TX) using
EscapeCommFunction(). I have successfully programmed PICs using these
instructions.

Let me know if you have more specific questions on a particular OS.

Regards,

Al Williams
AWC
*Solderless Stamp Prototypes at http://www.al-williams.com/awce.htm


-----Original Message-----
>> >        I am thinking of builing and a eprom programmer. I was wondering
if
>> >anyone knows how to write to and read from the serial and parallel
>> >ports. I know they are memory addressed. Any example could