> -----Original Message----- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mouse > Sent: 20 June 2015 13:54 > To: cctalk@classiccmp.org > Subject: Re: OT: learner kits (was: Re: using new technology on old machines) > > > Is there a reason to prefer 7400 series over CD4000 series logic? > > If you can find real TTL, yes, I would say so. It's less static-sensitive and it's > more tolerant to things like hooking two outputs together by mistake.
The pack recently mentioned was, I think 74LSxx TTL which is probably the most common and should in most cases be capable of replacing standard TTL. The other advantage of TTL is that is quicker. On the other hand CMOS is more tolerant of supply voltage. > > But note that there are many chips that have more or less TTL interfaces (TTL > voltages, TTLish numbers, and in some cases switching > thresholds) but are actually CMOS - the 74ALS series comes to mind. > > Of course, if someone somehow builds CMOS chips with TTL's ESD tolerance, > short-circuit tolerance, etc, then great. But that's not what I've seen. Most modern CMOS is "BE" series and so have ESD protection. > > /~\ The ASCII Mouse > \ / Ribbon Campaign > X Against HTML mo...@rodents-montreal.org > / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
