nurmi@haapana.tut.fi (Nurmi Jari) (11/09/89)
I am looking for a standard serial interface which could be implemented
using 0-5V CMOS devices. I have heard some second hand information that
there EXISTS some RS-232-xxx standard that might do.
If someone out there knows such standard, please let me know! I would be
pleased to have a) a verification of the existence of the 5V version
b) the identification of the standard (by what name can I find it) and then
c) what is the reference where I can read the specifications of it.
Please save me a lot of work!
Jari Nurmi # Tampere University of Technology
# /Signal Processing Laboratory
nurmi@tut.fi # PO Box 527, SF-33101 Tampere, Finland
(nurmi@tut.UUCP mcvax!tut!nurmi)# tel: +358 31 162 697 fax: 162 913henry@utzoo.uucp (Henry Spencer) (11/10/89)
In article <9820@etana.tut.fi> nurmi@tut.fi (Nurmi Jari) writes: >I am looking for a standard serial interface which could be implemented >using 0-5V CMOS devices... Well, the Maxim MAX232 family implements real RS232C using a +5 supply, and as I recall it's a CMOS device... It has its own voltage multiplier and inverter to turn +5 into +-9. This is by far the simplest and least painful solution unless you have special constraints. If "using 0-5V CMOS devices" means "on my own CMOS chip" or "with 4000-series chips only" or "with very low power consumption", then you do. Consider RS422, which is differential (2 wires per signal) but can be done with +5 only if my memory is correct. RS423 is sort of a modern RS232 using +-5. I can't think of any non-differential +5-only form offhand. Although the RS232 standard says (-3)-(+3) is the minimum swing, many RS232 receivers will react acceptably to a 0-3V swing. That's definitely non-standard, though. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu