Hi, I have checked on the messageboard and on google for making an parallel port interface on the pins of a 8051 or similar mcu.


I'm confused a little, because a 1 on a LPT pin is +5V and GND is GND, but on a 8051 derivate, I have seen that ports are always at +5V unless you pull them down to 0(GND?)


If I want to connect a 8051 to a PC parallel port to exchange data on D1 to D8, what should I connect then.


Just connect the GND of the LPT interface to the GND of the MCU and then directly connect the MCU pins to the datapins of the lpt interface ?



This seems to be a newbie question and I feel myself rather newbie too ;)

Fact is that I have a 300€ stepper motor controller here which has to be controlled by a parallel port.
I want to work under windows and because WIndows has about the worst timing possible, I will send commands over RS232 serial to the MCU and the MCU will then instruct the steppercard over a parallel interface using the correct timings.



Thanks for any possible help,

Bart