Line drivers & level restorers

[Ioannis]

I tried the Wiegand interface which is similar and maybe more difficult from the aspect that the line sits at +Vdd and drops low for 20 microseconds for every pulse transmitted.

It worked OK for 20 meters and the spec's say for over 100. A friend of mine tested this to be true.

So I believe with just an inverter or maybe a schmitt trigger even better resuts are to be expected.

Also a resistor (470-1200 ohm) at the end line to +Vdd will help.

Ioannis

[RussMartin]

Also a resistor (470-1200 ohm) at the end line to +Vdd will help.

So . . . a pull-up on the input at the receiving end?

[hatchethand1000]

I am currently driving from a pic pin through a 10k resistor to a pn2222a, base with the collector on ground and the emitter tied with 10K resistor to 5v. From the emitter out I am able to drive up to 300 ft to a similar circuit on the other end. In this configuration it is inverted and driven a good distance.

The 7414 with the schmit triggered input will restore a very similar output to the other end, inverted from the single input on the '14.

I am using this circuit configuration for PS/2 communication, works well.

K

[Ioannis]

So . . . a pull-up on the input at the receiving end?

Yes, that's right.

hatchethand1000:

I was a little confused by your configuration. Are you sure about this? It seems you have reverse biased the transistor.

Ioannis