well everybody out here is recommending the serial port for data transfering ... and i too fully agree with them ... but for experimentation and/or learning purpose if you want to use parallel port you can do it very easily...
the parallel port is divided or partioned into 4 parts.
1. DATA port
2. Status Port
3. Control Port
4. grounds (actually 8 of them )
i am referring to DB25 type of connector and not the old the old centronix port ...
well the parallel port can be configured in 3 modes
1. SPP (data out; status in; control bidirectional)
2.3. ECP and EPP (data is inout or bidirectional)
(my info on ECP might not be correct as i have never used it )(used only SPP and EPP)
these settings to be done in the BIOS area of the PC.
well to start with you can try out SPP
and i guess if you have only one connector coming out of your PC it is LPT1 and so your addressing will be 0x378 for data port, 0x379 for status port and 0x37A for control port...
you can easily search the pin details for the connector on the net ...
use data port from the PC to control any handshaking signals and use status port's 4/5 pins to read the 8 bit value in two steps ... using a 74ls244 to control the availability of higher order nibble and lower order nibble ... read both values and then concatenate them .....
in turbo c you can use inportb, inport, outportb, outport commands for performing transactions on the parallel port ...
just try it out and then graduate to EPP ... please notice if you are using old systems like early P1 or 486 they might not have EPP capability ....
i use an old P1 laptop system for doing all my interfacing experiments ... you see cant take risk even if i be extra careful ...
i have burned the parallel port controller once so i know .. that was due to a negligence on my part ... anyways to know more on parallel port read this book .... parallel port complete by jan axelson ....
happy interfacing ...
nitin
PS: this mail is only meant for novices like me and not for the punters in electronics ...
for them please directly use parallel port in EPP mode or better still use serial communication if there is a scarcity of port pins and distance is more or else if not much load is present on microcontroller we can save 0.8USD on MAX232 and directly connect to parallel port using 8 or 4 pins in SPP mode of parallel port and the ohter 4 for handshaking ... i guess the transfer will be much faster than serial transfer .. atleast 4 times faster ... but then i know in micro seconds or nano seconds it doesn't matter et el for novices ...
anyways TIM happy interfacing to arallel port and definitely give it a try .. its simple ,easy and interesting .....