understanding the pulse.

[mister_e]

any model or datasheet for your receiver? Is it possible that it's open-drain output type? what happen if you place a 1-10K pull-up resistor on it's output?

And yup it's Vil and Vih. it may differ from one i/o to another depending if it's an TTL or shmitt trigger one.

0.3 v seems realllllly low to me. If it works... maybe your scope miss some noise or maybe you have some better receiver / pic.

still thinking you're lucky