Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

ALT_INBUF_DIFF in cycloneII

is possible in cycloneII device use 2 pins INPUT for differential rs422 signal? In quartus2 the differential buffer for cyclone2 is not allowed!
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Hi Thielam,

I know the difference between RS232 and RS422. I also know that RS422 is not 0 to 3V3.

Maybe you should read: http://www.bb-elec.com/bb-elec/literature/tech/485appnote.pdf

It gives you all the information differential signaling, voltage levels, common mode, grounding, and so on.

One things is for sure: You should not connect RS422 directly to your FPGA.

Success, Ton