exxos's Atari, Amiga & retro forum

Hi

Iam looking for advice.
I want to translate and buffer 7 signals from mpu to outside world. What should I use to do it? It is one way only from 3.3 to 5v.
Can I just use something like 74AHC244 8bit Buffer/Line Driver 3 state? If yes what should I do with unused one? Just leave it floating?

It depends exactly what your doing... as TTL inputs will accept 3.3V as a HI anyway...

exxos wrote: 29 Sep 2020 17:14 It depends exactly what your doing... as TTL inputs will accept 3.3V as a HI anyway...

It is external signal which will be sent outside, maybe over the cables to external device. And I would like to protect mpu as well.

74AHCT244 or 74AHCT541 work well. You can also use 74HCT.

Just tie the unused input to ground or 3v3.

cmorley wrote: 29 Sep 2020 18:39 74AHCT244 or 74AHCT541 work well. You can also use 74HCT.

Just tie the unused input to ground or 3v3.

Thank you.

Lets see how it will work out. :)

Use a 74LVC244 with pull-up to 5V on the output (5V side).
It's a 3.3v device with 5V i/o support. I use it a lot of places exactly for this.
Rodolphe

I've been using 74AHCT245As for my VGA mod, since they only cost AUD 50c each and they do the job. If you only need a single-directional driver they work the same as the 244s (I just tie DIR to ground).