Hi!

This is a very simple example, how to control LPT output under WinNT-based system from fasm project with inpout32.dll by logix4u

and then, to drive the leds, just connect them to I/O port LPT. via 560 ohm resistors.

then, you can see the image of bits in real.

LPT already has resistors on bus (open collector)

yes, but these resistors are not designed for led driving.

the danger is to have too small resistors, and then, too high current, then, leds will burn.

tested and approuved by myself.

to know the value of the resistors on LPT, shortcut the out put with an amperemeter. the value displayed correspond to the the current in the resistor. mesure the voltage without load, then, you know the resistance by R=U/I

if the resistance is less than 560 ohm, your leds will probably burn if directlly connected. or know a shorter life.

typical resistor for red leds on 5V is 560ohms. but it works with 300 ohms too, more bright, and shorter life.

sure, i do not mind resistors. but i have not burn anyone on lpt yet. (maybe because i use old russian leds, which need 220V to be burn out )

very probable. can you mail me somes? in france, we don't have this kind of immortal components.

sure, i have some just do not know how to pack it so it will not be lost at mail also, it may look like exporting military technologies

here they are in use:


also there is a movie where you can see how do they blink

btw, i have inspected stuff what i have and found these resistors to +5V vary from 33 Ohm to 4700 Ohm, also one old LPT board i have has not OC output - it has TTL output without resistors at all.

sure, this way is just for quick testing without soldering anything - for more complex device there should be more correct electronic schema

regards!

so cute.
it reminds me my power amplifier.

if you want, i can write a shema for you, to build a matrix with the leds.

you need some CMOS or TTL logic too. and a holes-board (plaque à trou).
8*8 survivor dot matrix for LPT. plug and play!!!

or with only 8 leds and a motor, we can have a very long message. i made it a long time ago.

thanks, but i'm not sure i'll be interesting with power amplifier soon
i have interest in soldering and have a lot of parts for this as before i've been more interesting with electronics then programming, but last years have no time enough for this.
maybe next time i'll make something another intersting

regards!

Thank for you prog!
What about add manual input LPT adress ?
And what ASM, FLATASM?
ECP LPT it's bidirection port, how get DATA (swich pins to input)?
Thank's

I'm not sure what do you mean


any language which let you to call function from dll (if you mean inpout32.dll). I've been using fasm.


I had troubles with ECP (enchanced communicaton port) mode, so, I would suggest to use EPP or just bi-directional mode. Control register (say, 37Ah) has bit5 which has no output pin, but switches data port (378h) into input mode when set.

Also, it seems there are more articles about LPT now than PC with hardware LPT
And I have no currently Windows PC with LPT, but still can use it from Linux (in Linux I have access through C written program)

regards