I want to build a device to be controlled via the parallel port.

This device will use 4 pin, 2 for data output and two for input.

Pin3 is DATA , pin2 is CLOCK OUT , pin12 is INDEX IN , pin13 EXT CLK

In short I want to do an very simple imagesetter for cylinder.

The software I would like to meet next architecture:

Read 2 simple instructions in the form of ASCII character : 0 and 1  , to 

modify the logic state of pin3 (output data DB25 connector) in 0 or 1 logic level.

When read 0 ,the state of pin 3 is 0 logic. When read 1 state of pin 3 goes high , 1 logic .

These instructions are found written in a text file that I can load from pc (LOAD button)

Instructions appears as text lines 11001....001010101 without a maximum limit of characters ,

terminated by CR

These ascii lines are written in column , like : 

                                        1010010...

                                        0010010...

                                        ...............

                                        1001000... , also without a limit of lines ,

In short it is an a 1-bit bitmap converted to ascii.

How is read the instructions?

We create START button . It will start the clock , a clock defined by user.

Selectable in a range of 1 to 100000 counts per second. This clock will be outputed by the program on

pin 2 (for driving a stepper motor. Each count is 1 individual position on the cylinder)

Also i need the option for use external clock from pin13 

On each count the program reads and interprets an ascii instruction

Starting with the first left ascii from the first line.

Ends up reading the first line ,it awaits the appearance of an index pulse on pin12

This pulse will trigger reading the next line

And so it continues until the last ascii instruction

The clock will stop ONLY when the last index pulse will appear

here is a useful links for controlling paralel port

i allready test some simple exe to on off led on paralel port , and the inpout32.dll is working on xp

http://www.logix4u.net/parallel-port/16-inpout32dll-for-windows-982000ntxp

http://logix4u.net/component/content/article/14-parallel-port/15-a-tutorial-on-parallel-port-interfacing

http://www.logix4u.net/parallel-port/15-a-tutorial-on-parallel-port-interfacing