> void main (void)
> {
>
>         int a,b;
>
>         //outportb ( 888 + 1 , inportb ( 888 + 1 ) & 0xFE );
>         // THIS LINE MAKES NO DIFFERENCE EITHER WAY ^^^^^^^^^
>
>         aloop:
>
>         outportb ( 888 + 2 , 4); //Set control register
>         outportb ( 888 + 1 , 0xFF ); //Clear possible timeout
>         while ( ! kbhit ( ) ); //Wait for keystroke
>         outportb ( 888 + 4 , getch ( ) ); //Send keystroke
>         delay ( 10 ); //Wait for PIC to finish what it is doing
>         b = inportb ( 888 + 4 ); //Read in port contents
>         printf ( "%d\n" , b ); //print it
>         goto aloop; //Do it again
> };

> Sean Breheny wrote:
>
> > void main (void)
> > {
> >
> >         int a,b;
> >
> >         //outportb ( 888 + 1 , inportb ( 888 + 1 ) & 0xFE );
> >         // THIS LINE MAKES NO DIFFERENCE EITHER WAY ^^^^^^^^^
> >
> >         aloop:
> >
> >         outportb ( 888 + 2 , 4); //Set control register
> >         outportb ( 888 + 1 , 0xFF ); //Clear possible timeout
> >         while ( ! kbhit ( ) ); //Wait for keystroke
> >         outportb ( 888 + 4 , getch ( ) ); //Send keystroke
> >         delay ( 10 ); //Wait for PIC to finish what it is doing
> >         b = inportb ( 888 + 4 ); //Read in port contents
> >         printf ( "%d\n" , b ); //print it
> >         goto aloop; //Do it again
> > };
>
>
> I can see a few problems here, first of all, I would expect the parallel
> port to have it's control lines inactive and high when you first start
> off.  You therefore have to initialise them, but before you can
> initialise the port, you have to tell the PC what sort of port you wish
> to use.  This register is at your base address + 0x0402h and you need to
> write the value 0x80h for the EPP port.  You can now write the value
> XXXX0100 B  into the control register to initialise this port (base
> address + 2).  Now you need to set the data direction bit to a '1' for an
> inport command and a '0' for an outport command.
>
> By the way, this information and more can be found at
> http://www.geocities.com/SiliconValley/Bay/8302/epp.htm/ for the EPP port
> and http://www.senet.com.au/~cpeacock/ for everythig else!
>
> Hope this helps,
>
> Brian.
>

>Hello to all who responded about my EPP port problems,
>
>I finally fixed my problem, and it was a very simple one: my routine was
>not fast enough. The EPP port has about a 10uS timeout timer on most PCs.
>If the PIC doesn't ack the PC's data strobe within 10uS, it finishes the
>cycle right then and there. My PIC routene was taking about 15uS to
>create the ack. When I lowered it to about 5uS, it worked fine.
>
>Apparently all the strange behavior with the WAIT line pulsing multiple
>times was just due to the PIC pin's very fast rise time, combined with
>cable length and my fast counter that I was using to detect it.
>
>ALSO, the reason for the "lag" phenomenon was that the PIC's code to get
>data from the PC was working, but its code to send data TO the PC was
>where the timeout was occuring. SO, the cycle was enbding before the
>PIC's output latches were being loaded with the new value.
>
>Thanks to all,
>
>Sean
>
>P.S. Now that I have fixed this proble, I have found another having to do
>with the SRAM in my DSO, so I may have some more questions for all of you
>soon :)