Post by thread:[AD] New TTL to RS-232 converter

I don't know how many times I've built up a quick TTL to RS-232 converter on a protoboard, or included the circuit on prototype boards for debugging. About a month ago this came up again. I was transitioning a board from the debugging version to first manufacturable prototype, but several people would still need to access the debugging serial port from a PC. At manufacturing time this port is used to set configuration and is accessed from the bottom of the board via pogo pins. I wanted to take up minimal space for debugging support, so I added a 4 pin header with 5V, GND, RX, and TX. We are getting a bunch of boards made that various people need to work with, so this time I decided to do the TTL to RS-232 converter right. Instead of just making the dozen or so to cover the immediate need, I made a bunch and they are now available for sale. They are $25 in singles, or $89 for a 5 pack. For details, go to http://www.embedinc.com/products and check out the RSLink. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

olin_piclist@embedinc.com (Olin Lathrop) wrote: > Instead of just making the dozen or so to cover the immediate need, > I made a bunch and they are now available for sale. They are $25 in > singles, or $89 for a 5 pack. For details, go to > http://www.embedinc.com/products > and check out the RSLink. Looks good, except that your usage of the terms "mark" and "space" in your description is contrary to convention. A serial line idles in the "mark" state (TTL high, RS-232 negative voltage) and a start bit is the "space" state (TTL low, RS-232 positive voltage). -- Dave Tweed

At 18.03 2005.03.20 -0800, you wrote: >spam_OUTolin_piclistTakeThisOuTembedinc.com (Olin Lathrop) wrote: >> Instead of just making the dozen or so to cover the immediate need, >> I made a bunch and they are now available for sale. They are $25 in >> singles, or $89 for a 5 pack. For details, go to >> http://www.embedinc.com/products >> and check out the RSLink. > >Looks good, except that your usage of the terms "mark" and "space" in your >description is contrary to convention. A serial line idles in the "mark" >state (TTL high, RS-232 negative voltage) and a start bit is the "space" >state (TTL low, RS-232 positive voltage). What is exactly the "break condition", by the way?

>> RS-232 (EIA/TIA-232) > What is exactly the "break condition", by the way? In asynchronous mode, each "byte" (data payload may vary from 5 to 9 bits, 8 is most common) is enclosed between a start bit and a stop bit. When idling (no transmission), the line sits at negative voltage. A start bit is a positive voltage for 1 bit time. This is followed by the data bits of either voltate. The byte is terminated by a stop bit of negative voltage for 1 bit time or longer. If the stop bit is missing, then the UART will generate a framing error. A break is when the line is left in the postive voltage level for many character times (usually 100ms to 300ms (some old equipment had the concept of short breaks and long breaks)) to force an exception through the framing error process. Formerly, it was for an out-of-band interrupt from the terminal to the host. Lee Jones

At 01.34 2005.03.21 -0800, you wrote: >>> RS-232 (EIA/TIA-232) > >> What is exactly the "break condition", by the way? > >In asynchronous mode, each "byte" (data payload may vary from >5 to 9 bits, 8 is most common) is enclosed between a start bit >and a stop bit. > >When idling (no transmission), the line sits at negative voltage. >A start bit is a positive voltage for 1 bit time. This is followed >by the data bits of either voltate. The byte is terminated by a >stop bit of negative voltage for 1 bit time or longer. If the stop >bit is missing, then the UART will generate a framing error. > >A break is when the line is left in the postive voltage level for >many character times (usually 100ms to 300ms (some old equipment >had the concept of short breaks and long breaks)) to force an >exception through the framing error process. Formerly, it was >for an out-of-band interrupt from the terminal to the host. Thanks, now it's all clear, you write like a perfect manual. ;) > > Lee Jones

Dave Tweed wrote: > Looks good, except that your usage of the terms "mark" and "space" in > your description is contrary to convention. A serial line idles in the > "mark" state (TTL high, RS-232 negative voltage) and a start bit is the > "space" state (TTL low, RS-232 positive voltage). Oops. I just updated the web page to remove mention of "mark" and "space". ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

James Newton, Host wrote: > Or you could buy the same thing from me for $17 built into a DB9 back > shell, with a cable, with RTS and CTS also converted Well it's not the same thing, but certainly similar. Yours is the choice if you want RTS and CTS. Mine will be more handy if you don't want to put the specific 6 pin connector on the board that yours requires. I noticed that it's not actually your product, but you say you are selling it. How does that work? Is piclist.com set up as an online store with a standard markup? Who does the order fulfillment? Who handles the support issues? Or is this product a one-off special case that you arranged with the designer? ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

William Chops Westfield wrote: > Is it just me, or is the 'standard' max232 pinout REALLY SUCKY? It is what it is, although I would like to see a few pins moved around too. For example, all the TTL signals on one side and the RS-232 signals on the other. All the various charge pump caps accross adjacent pins. Oh, well, it's just something you deal with like most any other IC. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

ThePicMan wrote: > What is exactly the "break condition", by the way? A break is when the line is held in the non-idle state for more than a whole character time. The receiving UART detects this by the stop bit not being the right polarity, since a valid stop bit is at the line idle level. This is usually called a "framing error" in receiving UART documentation. Note however that framing errors can be caused by other things, like a buad rate mismatch. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

On Mar 21, 2005, at 5:53 AM, Herbert Graf wrote: >> Is it just me, or is the 'standard' max232 pinout REALLY SUCKY? > > What don't you like about it? I'd say it's pinout > makes a good amount of sense. Like Olin, I'd like to see all the ttl levels on one side of the chip and non-ttl on the other side. I note that TTL logic has been doing this sort of thing for a while (74x573 vs 74x373, etc), I was just sort of hoping for similar care on what I thought were more modern chips... BillW

It came out at $19 + $5 S/H. But I bought it anyway. --Bob James Newton, Host wrote: {Quote hidden}>Or you could buy the same thing from me for $17 built into a DB9 back shell, >with a cable, with RTS and CTS also converted > >http://www.piclist.com/techref/io/serial/RCL1.htm > >And I just got the next shipment, so I'll be removing the "Backordered" sign >first think Monday morning. > >--- >James. > > > > > >>{Original Message removed}

OOPS! I've fixed that. Thanks for letting me know! --- James. {Quote hidden}> -----Original Message----- > From: .....piclist-bouncesKILLspam@spam@mit.edu > [piclist-bouncesKILLspammit.edu] On Behalf Of Howard Winter > Sent: 2005 Mar 21, Mon 06:08 > To: Microcontroller discussion list - Public. > Subject: RE: [AD] New TTL to RS-232 converter > Importance: Low > > On Mon, 21 Mar 2005 09:20:09 +0100 (MET), Jan-Erik Soderholm wrote: > > > James Newton, Host wrote : > > > > > Or you could buy the same thing from me... > > > > Are you sure ??? > > The page says: "Available In the USA"... > > And when you click on the <Buy Now> button, it shows the > price as $19 in the shopping cart, not $17. > > Cheers, > > > Howard Winter > St.Albans, England > > > -

I've added an international shipping option. And before some one asks, yes it really does cost that much for me to ship it internationally. I have found that I need to send via registered mail to avoid loss in customs and that requires a trip to the post office, standing in line, etc... If you want one or two I can probably work out something less costly for trusted members of the list. (why did I say that....) --- James. > {Original Message removed}

> > Dave Tweed wrote: > > Looks good, except that your usage of the terms "mark" and > "space" in > > your description is contrary to convention. A serial line > idles in the > > "mark" state (TTL high, RS-232 negative voltage) and a start bit is > > the "space" state (TTL low, RS-232 positive voltage). > > Oops. I just updated the web page to remove mention of > "mark" and "space". For information on that subject see: http://www.piclist.com/techref/io/serial/rs232sigs.htm --- James Newton: PICList webmaster/Admin .....jamesnewtonKILLspam.....piclist.com 1-619-652-0593 phone http://www.piclist.com/member/JMN-EFP-786 PIC/PICList FAQ: http://www.piclist.com

> Or you could buy the same thing from me for $17 built into a > DB9 back shell, with a cable, with RTS and CTS also converted > > www.piclist.com/techref/io/serial/RCL1.htm > > And I just got the next shipment, so I'll be removing the > "Backordered" sign first think Monday morning. I have good news and bad news: The good news is: Several people just ordered (apparently based on this thread?) and I have been able to fill those orders. If you were charged $19 rather than $17, please let me know and I will refund the $2. The price should have been $17 plus $5 S&H but for a little while the PayPal amount actually came out as $19 due to fumble fingers on my part. The bad news is: I'm out again! So the "backorder" has to stay on the site. I do have another batch on order and it should arrive before the 28th. --- James Newton: PICList webmaster/Admin EraseMEjamesnewtonspam_OUTTakeThisOuTpiclist.com 1-619-652-0593 phone http://www.piclist.com/member/JMN-EFP-786 PIC/PICList FAQ: http://www.piclist.com

James Newton, Host wrote : > I've added an international shipping option. And before > some one asks, yes it really does cost that much for > me to ship it internationally. So, if I understand correctly, that's an *additional* $10 to the $5, for a total of $15 in shipping, right ? Fine... > I have found that I need to send via registered mail to > avoid loss in customs and that requires a trip to the post > office, standing in line, etc... > > If you want one or two I can probably work out something > less costly for trusted members of the list. (why did I say that....) Now, let me help you. I've at several occations helped US'ers that have been totaly perplexed when asked to ship "overseas"... The "Global Priority Mail - Flat-rate Envelope (Small)" costs $5 to ship to Sweden. It can take up to 4 punds and up to a size of 6" x 10". One standard (3 meter) RS232 cable with a 9-pin DB connector at each end is about 0.5 punds. Now your cable is just 0.1 meter, so it probably weights way less then my 3 meter cable. Let's say 0.2 punds anyway. So, all i all, you could probably ship something like between 10 and 20 of your RCL-1 in one of those flat rate envelopes for $5.00 to Sweden. If the size (6" x 10") of the "small" flat rate envelope isn't enough, there is a "large" one that takes up to 9-1/2" x 12-1/2" (still up to 4 pounds) that ships to Sweden for $9.00 $15 shipping for *1* unit? He he... :-) Heck, I got a copy of the "USB Complete" shipped in just a few days using the $9 flat rate Global Priority Mail envelope. And that was over 2 pounds... Now, with that said, yes I know, it's up to the seller to set the price and for me to either accept or just forget about it. I've no problem with that... :-) See also : http://ircalc.usps.gov/ for an international shipping cost calculator and : www.usps.com/global/globalprioritymail.htm for info about the "Global Prioroty Mail" offers. The whole idea that shipping "international" or "overseas" is something "special" is just ridiculous, IMHO. Best Regards, Jan-Erik.

The $2 are on their way to you via PayPal. Sorry about that. --- James. {Quote hidden}> -----Original Message----- > From: piclist-bouncesspam_OUTmit.edu > [@spam@piclist-bouncesKILLspammit.edu] On Behalf Of Bob Axtell > Sent: 2005 Mar 21, Mon 09:24 > To: Microcontroller discussion list - Public. > Subject: Re: [AD] New TTL to RS-232 converter > Importance: Low > > It came out at $19 + $5 S/H. > > But I bought it anyway. > > --Bob > > James Newton, Host wrote: > > >Or you could buy the same thing from me for $17 built into a > DB9 back > >shell, with a cable, with RTS and CTS also converted > > > >www.piclist.com/techref/io/serial/RCL1.htm > > > >And I just got the next shipment, so I'll be removing the > "Backordered" > >sign first think Monday morning. > > > >--- > >James.

Hi. About finding the page with the "RSLink" TTL/RS232 converter... Olin Lathrop wrote : > For details, go to > http://www.embedinc.com/products and check > out the RSLink. Now, this URL *does* work, but... If you start on the EmbedInc *main* homepage and select "Design" -> "Product Descriptions" from the main menu, you end up on a page with the URL : "http://www.embedinc.com/products.asp" Note that the only difference is the ".asp" extension. This is *not* the same page as the one without the .asp ext. Quite confusing, IMHO. B.t.w, is it possible at all to find the TTL/RS232 page if starting from the main EmbedInc home page ? Best Regards, Jan-Erik.

Jan-Erik Soderholm wrote: >> For details, go to >> http://www.embedinc.com/products and check >> out the RSLink. > > Now, this URL *does* work, but... > > If you start on the EmbedInc *main* homepage and select > "Design" -> "Product Descriptions" from the main menu, > you end up on a page with the URL : > "http://www.embedinc.com/products.asp" > > Note that the only difference is the ".asp" extension. > This is *not* the same page as the one without the .asp ext. > > Quite confusing, IMHO. I agree. > B.t.w, is it possible at all to find the TTL/RS232 page > if starting from the main EmbedInc home page ? No. The problem is that someone else created the main pages using some tool to "automatically" create them, and I've been trying to arrange for them to update the appropriate links. This is taking far longer than it should. I suppose I could upload the HTML and try to edit it manually, but was hoping I wouldn't need to resort to that. The stuff produced by the layered software looks like gobbledygook. I'll try to look at this tonight. I'm getting fed up waiting for this other guy to fix this too. Sorry about the confusion. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

Olin Lathrop wrote : > > B.t.w, is it possible at all to find the TTL/RS232 page > > if starting from the main EmbedInc home page ? > > No. The problem is that someone else created the main pages > using some tool to "automatically" create them, and I've been > trying to arrange for them to update the appropriate links. ... Ah, I see. He, I've just begun using something similar to produce my own "new" home page (new domain that will replace the one you have linked to on your PIC dev-toolkit page, b.t.w. I'll let you know in due time, of course). This is also a point-n-ckick, drag-n-drop kind of tool where you never see the HTML (well in the final "built" site, yes). So far it looks good. If I run into similar problems, I just hope that everyone have forgotten about that I said anyhing about your site... :-) Jan-Erik. PS: The tool I use is available here if someone is interested : http://www.effectivestudios.com/Overview.htm.

Jan-Erik Soderholm wrote: >> No. The problem is that someone else created the main pages >> using some tool to "automatically" create them, and I've been >> trying to arrange for them to update the appropriate links. ... > > Ah, I see. He, I've just begun using something similar to produce > my own "new" home page (new domain that will replace the one > you have linked to on your PIC dev-toolkit page, b.t.w. I'll let you > know in due time, of course). I just looked at the stuff on our web site, and what a mess. Some of the words are in images instead of text. I guess that explains why the page doesn't resize properly. I really dislike these web pages designed more to show off the web designer than the content, and that detract from usability on top of the. I like it even less when it's my own web site. I managed to find where the PRODUCTS link was and changed it to "Standard Products" and redirected it to the products.htm page. Unfortunately the "Designs" heading turned out to be buried in an image somewhere, so I guess I'm stuck with that. I guess missing content is better than misleading content. In the mean time, you can still view all the PIC related products at http://www.embedinc.com/products. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

Just a quick note to let everyone know the TTL-RS232 converters are back in stock, for the moment, at http://www.piclist.com/techref/io/serial/rcl1.htm and that I have raised the price by one whole dollar to $18 each. I have only a few left from this last shipment, but more will be on the way in the next few weeks. --- James Newton: PICList webmaster/Admin KILLspamjamesnewtonKILLspampiclist.com 1-619-652-0593 phone http://www.piclist.com/member/JMN-EFP-786 PIC/PICList FAQ: http://www.piclist.com