On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan <jkirwan@easystreet.com> wrote:>On Fri, 06 Jan 2006 07:35:49 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote: > >>On Fri, 06 Jan 2006 09:46:11 GMT, Robert Baer >><robertbaer@earthlink.net> wrote: >> >>[snip] >> >>> There may still be some devices that will convert RS-232 levels to >>>TTL and some that go the other way. >> >>RS-232 -> TTL = MC1489 >> >>TTL -> RS-232 = MC1488 >> >>These chips are still available more than 40 years after I designed >>them ;-) >> >>These chips adhere to the original RS-232 spec. >><snip> > >1488 requiring several supplies -- and runs hot as a pistol, too.360mW typical ;-)>I've >got a box of both; they were about all there was to use in the market >and worked well when I was using them; but don't use them much now >because of the power requirements (especially the 1488) and the >serious heat to be removed (again the 1488 much more than the 1489, if >memory serves, but neither of them slouches in the heating >department.) > >JonKeep in mind this was early '60's. Quite a few process capability improvements since then. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
RS232 Voltage Levels
Started by ●January 5, 2006
Reply by ●January 6, 20062006-01-06
Reply by ●January 6, 20062006-01-06
On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan <jkirwan@easystreet.com> Gave us:>On Fri, 06 Jan 2006 07:35:49 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote: > >>On Fri, 06 Jan 2006 09:46:11 GMT, Robert Baer >><robertbaer@earthlink.net> wrote: >> >>[snip] >> >>> There may still be some devices that will convert RS-232 levels to >>>TTL and some that go the other way. >> >>RS-232 -> TTL = MC1489 >> >>TTL -> RS-232 = MC1488 >> >>These chips are still available more than 40 years after I designed >>them ;-) >> >>These chips adhere to the original RS-232 spec. >><snip> > >1488 requiring several supplies -- and runs hot as a pistol, too. I've >got a box of both; they were about all there was to use in the market >and worked well when I was using them; but don't use them much now >because of the power requirements (especially the 1488) and the >serious heat to be removed (again the 1488 much more than the 1489, if >memory serves, but neither of them slouches in the heating >department.) >Sounds like a poorly implemented utilization. Sum Ting Wong must have done the design.
Reply by ●January 6, 20062006-01-06
On Fri, 06 Jan 2006 18:54:51 GMT, Roy L. Fuchs wrote:> On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan > <jkirwan@easystreet.com> Gave us: > >>On Fri, 06 Jan 2006 07:35:49 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote: >> >>>On Fri, 06 Jan 2006 09:46:11 GMT, Robert Baer >>><robertbaer@earthlink.net> wrote: >>> >>>[snip] >>> >>>> There may still be some devices that will convert RS-232 levels to >>>>TTL and some that go the other way. >>> >>>RS-232 -> TTL = MC1489 >>> >>>TTL -> RS-232 = MC1488 >>> >>>These chips are still available more than 40 years after I designed >>>them ;-) >>> >>>These chips adhere to the original RS-232 spec. >>><snip> >> >>1488 requiring several supplies -- and runs hot as a pistol, too. I've >>got a box of both; they were about all there was to use in the market >>and worked well when I was using them; but don't use them much now >>because of the power requirements (especially the 1488) and the >>serious heat to be removed (again the 1488 much more than the 1489, if >>memory serves, but neither of them slouches in the heating >>department.) >> > > Sounds like a poorly implemented utilization. Sum Ting Wong must > have done the design.They always worked well for me - and everyone else in the industry for about 20 years... Bob
Reply by ●January 6, 20062006-01-06
On Fri, 06 Jan 2006 18:54:51 GMT, Roy L. Fuchs <roylfuchs@urfargingicehole.org> Gave us:>On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan ><jkirwan@easystreet.com> Gave us: > >>On Fri, 06 Jan 2006 07:35:49 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote: >> >>>On Fri, 06 Jan 2006 09:46:11 GMT, Robert Baer >>><robertbaer@earthlink.net> wrote: >>> >>>[snip] >>> >>>> There may still be some devices that will convert RS-232 levels to >>>>TTL and some that go the other way. >>> >>>RS-232 -> TTL = MC1489 >>> >>>TTL -> RS-232 = MC1488 >>> >>>These chips are still available more than 40 years after I designed >>>them ;-) >>> >>>These chips adhere to the original RS-232 spec. >>><snip> >> >>1488 requiring several supplies -- and runs hot as a pistol, too. I've >>got a box of both; they were about all there was to use in the market >>and worked well when I was using them; but don't use them much now >>because of the power requirements (especially the 1488) and the >>serious heat to be removed (again the 1488 much more than the 1489, if >>memory serves, but neither of them slouches in the heating >>department.) >> > > Sounds like a poorly implemented utilization. Sum Ting Wong must >have done the design.PS: I refer to the circuit designer, not the chip.
Reply by ●January 6, 20062006-01-06
On Fri, 06 Jan 2006 11:44:21 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:>On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan ><jkirwan@easystreet.com> wrote: > >>On Fri, 06 Jan 2006 07:35:49 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote: >> >>>On Fri, 06 Jan 2006 09:46:11 GMT, Robert Baer >>><robertbaer@earthlink.net> wrote: >>> >>>[snip] >>> >>>> There may still be some devices that will convert RS-232 levels to >>>>TTL and some that go the other way. >>> >>>RS-232 -> TTL = MC1489 >>> >>>TTL -> RS-232 = MC1488 >>> >>>These chips are still available more than 40 years after I designed >>>them ;-) >>> >>>These chips adhere to the original RS-232 spec. >>><snip> >> >>1488 requiring several supplies -- and runs hot as a pistol, too. > >360mW typical ;-)Connected and driving, it sure seemed like more! But I think the RthetaJA was about 150. Which meant 'damned hot' even at .36W. With as little as 4k or so on the 1489 receiver inputs, that was getting near another tenth watt dissipation per connected input at that end, with +/-12-15V signaling applied, too. Part of the spec, sure; but still ... There was an advantage to all this, I suppose. I could find the 1488 and 1489 parts blindfolded. Just casually feel where the heat is emanating from. ;)>>I've >>got a box of both; they were about all there was to use in the market >>and worked well when I was using them; but don't use them much now >>because of the power requirements (especially the 1488) and the >>serious heat to be removed (again the 1488 much more than the 1489, if >>memory serves, but neither of them slouches in the heating >>department.) > >Keep in mind this was early '60's. > >Quite a few process capability improvements since then.No doubt. I didn't get around to using them until much later, though, being that I was in grade school in the early '60s. Jon
Reply by ●January 6, 20062006-01-06
Bob Stephens wrote:> On Fri, 06 Jan 2006 18:54:51 GMT, Roy L. Fuchs wrote: > > > On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan > > <jkirwan@easystreet.com> Gave us: > > > >>On Fri, 06 Jan 2006 07:35:49 -0700, Jim Thompson > >><To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote: > >> > >>>On Fri, 06 Jan 2006 09:46:11 GMT, Robert Baer > >>><robertbaer@earthlink.net> wrote: > >>> > >>>[snip] > >>> > >>>> There may still be some devices that will convert RS-232 levels to > >>>>TTL and some that go the other way. > >>> > >>>RS-232 -> TTL = MC1489 > >>> > >>>TTL -> RS-232 = MC1488 > >>> > >>>These chips are still available more than 40 years after I designed > >>>them ;-) > >>> > >>>These chips adhere to the original RS-232 spec. > >>><snip> > >> > >>1488 requiring several supplies -- and runs hot as a pistol, too. I've > >>got a box of both; they were about all there was to use in the market > >>and worked well when I was using them; but don't use them much now > >>because of the power requirements (especially the 1488) and the > >>serious heat to be removed (again the 1488 much more than the 1489, if > >>memory serves, but neither of them slouches in the heating > >>department.) > >> > > > > Sounds like a poorly implemented utilization. Sum Ting Wong must > > have done the design. > > They always worked well for me - and everyone else in the industry for > about 20 years...The RS-232 specification was originally designed as an interface for electro-mechanical printers, using discrete transistor logic to convert signals coming over telephone pair hooked up to the old relay-switched public telephone system into successive ASCII characters printed on a rol of paper. Search on "Telex" and "TWX". It up-graded the original 50/75 character-per-second telex system whose only active components were electro-mechanical - essentially relay logic. You should be able to find a history of the ASR-33 terminal somewhere on the web - that was the cheap version of the ASR-35 bought by people who had to handle significant amounts of TWX traffic. -- Bill Sloman, Nijmegen
Reply by ●January 6, 20062006-01-06
On Fri, 6 Jan 2006 11:37:40 -0800, Bob Stephens <roberts@dcxchol.com> wrote:>On Fri, 06 Jan 2006 18:54:51 GMT, Roy L. Fuchs wrote: > >> On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan >> <jkirwan@easystreet.com> Gave us: >> >>>On Fri, 06 Jan 2006 07:35:49 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote: >>> >>>>On Fri, 06 Jan 2006 09:46:11 GMT, Robert Baer >>>><robertbaer@earthlink.net> wrote: >>>> >>>>[snip] >>>> >>>>> There may still be some devices that will convert RS-232 levels to >>>>>TTL and some that go the other way. >>>> >>>>RS-232 -> TTL = MC1489 >>>> >>>>TTL -> RS-232 = MC1488 >>>> >>>>These chips are still available more than 40 years after I designed >>>>them ;-) >>>> >>>>These chips adhere to the original RS-232 spec. >>>><snip> >>> >>>1488 requiring several supplies -- and runs hot as a pistol, too. I've >>>got a box of both; they were about all there was to use in the market >>>and worked well when I was using them; but don't use them much now >>>because of the power requirements (especially the 1488) and the >>>serious heat to be removed (again the 1488 much more than the 1489, if >>>memory serves, but neither of them slouches in the heating >>>department.) >>> >> >> Sounds like a poorly implemented utilization. Sum Ting Wong must >> have done the design. > >They always worked well for me - and everyone else in the industry for >about 20 years... > > >BobWhat is "Fuchs"? Shorthand for fuck-head? I plonked him weeks ago. I recommend everyone else do the same. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●January 6, 20062006-01-06
Jim Thompson <To-Email-Use-The-Envelope-Icon@my-web-site.com> wrote:> What is "Fuchs"?German word for "FOX" -- Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
Reply by ●January 6, 20062006-01-06
On Fri, 06 Jan 2006 03:10:09 GMT, David Tweed <dtweed@acm.org> wrote:>Charles Jean wrote: >> Thanks Mark, for clearing that up. Does this look like the proper way >> to send the chip an "A", then, with the mode set at "normal" >> TTL(0-5V)? What are the indeterminate voltage limits? Any need for a >> delay prior to sending the next character"? >> >> |------<--8 character bits---->-------------- >> +5V_|___ ___ ___ ______ >> | |S | | | | | | | | | | | >> | |T | | | | |2 STOP >> | |A | | | | |BITS > +2.0V-|--|R-|--|--------------|--|--|-------------- >> | |T | | | | | >> | | | | | | |INDETERMINATE >> | |B | | | | |VOLTAGE >> | |I | | | | |REGION >> | |T | | | | | > +0.8V-|--|--|--|--------------|--|--|-------------- >> | | | | | | | >> | | | | | | | >> | | | | | | | >> | | | | | | | >> 0V_| |__| |--|--|--|--|--| |__| | | >> 0 1 0 0 0 0 0 1 0 1 1 >> LSB MSB >> >> Bit width = 1/9600 seconds = 104.2 microseconds > >No delay should be required. > >-- Dave Tweed___ I'm the OP of this thread and would like to thank everyone for such a voluminous and knowledeable response! For those that wanted to know, the chip is the SV2000 video interface chip from http://www.speechchips.com. It inputs serial ASCII data and converts to an RS170 composite video encoded stream. It is supposed to give a 9 line X 16 character display, with a standard ASCII font as well as user-defined fonts. Control commands are preceeded by ASCII 27(ESC). It has been marked down from $20 from $10. I already had a portable BW TV with a composite video input, so I thought I might try it. By bit-banging I wouldn't use the precious single UART of my uC, and only one of its output pins. As you can see from the data sheet, the connection on pin 6 allows for either "normal" or "inverted" TTL levels to be used. I think I could have saved lots of confusion by rephrasing my question to: "What's the idling voltage of normal and inverted TTL serial lines?" I can write the program to have the line at pin 3 idle at either 0 or 5 volts, and I had a 50-50 chance of having pin 6 wired correctly. Just lazy again. Sorry if I caused any trouble.
Reply by ●January 7, 20062006-01-07
Richard Crowley wrote:> > "Jim Thompson" wrote ... > > "techie_alison" wrote: > >>"Grant Edwards" wrote ... > >>> Charles Jean wrote: > >>> > >>> Who's Mark? > >>> > > [snip] > > > > Space's brother ?:-) > > ROTFL! :-)) > > (But likely lost on the younger crowd.)Yeah, they don't know what they missed by never working on the old AP & UPI newswire KSR33 teletypes on a leased loop. -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida
