From: Anders W. <di...@ds...> - 2007-05-28 20:25:57
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Hi Everyone, Is it safe to connect a 5v serial uart to the gumstix's 3v uarts? cheers Anders |
From: Dave H. <dhy...@gm...> - 2007-05-28 20:29:10
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HI Anders, > Is it safe to connect a 5v serial uart to the gumstix's 3v uarts? According to the datasheet - No. -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |
From: Anders W. <di...@ds...> - 2007-05-28 21:07:41
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Thanks Dave!<br> <br> Can you recommend any voltage level converters? Also, does anyone one if the breagkout-gs is compatible with the verdex?<br> <br> Anders<br> <br> Dave Hylands wrote: <blockquote cite="mid...@ma..." type="cite"> <pre wrap="">HI Anders, </pre> <blockquote type="cite"> <pre wrap="">Is it safe to connect a 5v serial uart to the gumstix's 3v uarts? </pre> </blockquote> <pre wrap=""><!----> According to the datasheet - No. </pre> </blockquote> </body> </html> |
From: Dave H. <dhy...@gm...> - 2007-05-28 22:20:25
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HI Anders, > Can you recommend any voltage level converters? It depends on what you're trying to do. > Also, does anyone one if the breagkout-gs is compatible with the verdex? It should be. You'd need to compare the chart for the connex: http://docswiki.gumstix.com/New_60pin_connector_chart with the one for the verdex: http://docswiki.gumstix.com/Verdex_60pin_connector_chart You'll find that most of the signals are identical. So, it really depends on what you're trying to do with it. -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |
From: Anders W. <di...@ds...> - 2007-05-29 00:31:44
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> </head> <body bgcolor="#ffffff" text="#000000"> Hi Dave<br> <blockquote cite="mid...@ma..." type="cite"> <blockquote type="cite"> <pre wrap="">Can you recommend any voltage level converters? </pre> </blockquote> <pre wrap=""><!----> It depends on what you're trying to do. </pre> </blockquote> the gum needs to talk to another device that talks 0-5v TTL. <br> <br> Ive a couple of 3v TTL <-> RS232 and 5v TTL <-> RS232 chips i can connect but that is gonna be a lot of components for little bang. Seems this might be common enough problem that people have created a dedicated chip for it.<br> <br> cheers<br> Anders<br> </body> </html> |
From: Dave H. <dhy...@gm...> - 2007-05-29 00:44:32
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Hi Anders, > the gum needs to talk to another device that talks 0-5v TTL. So, here's a solution using a couple of MOSFETs: <http://www.headfuzz.co.uk/?q=node/46> While originally intended for i2c, this technique works equally well for serial. Most 5v devices will interpret a 3.3v signal properly, so once solution is to connect the 3.3v Tx line to the 5v Rx line, and use a resistor divider in the other direction. Something like 3 4.7v resistors in a row: gnd --- resistor --- resistor -- 3.3v Rx --- resistor --- 5v Tx And you could also buy a dedicated IC: http://www.idt.com/?genID=QS3306A&source=products_genericPart_QS3306A (see this tech note) http://www.idt.com/products/files/7530/AN_11.pdf?CFID=1643180&CFTOKEN=53116081 Another dedicated IC is: http://www.fairchildsemi.com/pf/74/74LVX4245.html -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |
From: mtd <mt...@ce...> - 2007-05-29 11:19:47
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Dave Hylands wrote: > Hi Anders, > >> the gum needs to talk to another device that talks 0-5v TTL. > Most 5v devices will interpret a 3.3v signal properly, so once I slightly disagree. It depends on communication speed and whether you are communicating with ttl, ttl-compatible-cmos or cmos input. > solution is to connect the 3.3v Tx line to the 5v Rx line, and use a > resistor divider in the other direction. > > Something like 3 4.7v resistors in a row: > gnd --- resistor --- resistor -- 3.3v Rx --- resistor --- 5v Tx there is also simpler circuit, which depends on internal (or external) schottky connected to Vdd and connect IOs following way: 3.3V in --- R ---- 5V out where R is about 100kOhms. value of resistor depends on io tollerance and should be selected carefully. -- Martin Tomasek |
From: Marc N. <gee...@gm...> - 2007-05-29 00:44:57
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Anders, The Sparkfun "shifters" that I directed you to will do that. They'll actually do pretty much any voltage combo you like -- they're sourced from each drive side with a clever transistor array setup. So, you can do: - 12vdc serial to 5vdc - 5vdc to to 3.3vdc - 3.3vdc to 1.8vdc Pretty much any esoteric combination in between. If you know what you're doing, just the transistor array. -marc On 5/28/07, Anders Wallsson <di...@ds...> wrote: > > Hi Dave > > Can you recommend any voltage level converters? > > It depends on what you're trying to do. > > the gum needs to talk to another device that talks 0-5v TTL. > > Ive a couple of 3v TTL <-> RS232 and 5v TTL <-> RS232 chips i can connect > but that is gonna be a lot of components for little bang. Seems this might > be common enough problem that people have created a dedicated chip for it. > > cheers > Anders > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > |
From: Anders W. <di...@ds...> - 2007-05-29 05:16:05
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Thanks Dave and Marc!<br> <br> <br> <br> Marc Nicholas wrote: <blockquote cite="mid...@ma..." type="cite">Anders,<br> <br> The Sparkfun "shifters" that I directed you to will do that. They'll actually do pretty much any voltage combo you like -- they're sourced from each drive side with a clever transistor array setup. <br> <br> So, you can do:<br> <br> - 12vdc serial to 5vdc<br> - 5vdc to to 3.3vdc<br> - 3.3vdc to 1.8vdc<br> <br> Pretty much any esoteric combination in between.<br> <br> If you know what you're doing, just the transistor array. <br> <br> -marc<br> <br> <div><span class="gmail_quote">On 5/28/07, <b class="gmail_sendername">Anders Wallsson</b> <<a href="mailto:di...@ds...">di...@ds...</a>> wrote:</span> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> <div bgcolor="#ffffff" text="#000000">Hi Dave<br> <blockquote cite="http://mid...@ma..." type="cite"><span class="q"> <blockquote type="cite"> <pre>Can you recommend any voltage level converters? </pre> </blockquote> <pre>It depends on what you're trying to do. </pre> </span></blockquote> the gum needs to talk to another device that talks 0-5v TTL. <br> <br> Ive a couple of 3v TTL <-> RS232 and 5v TTL <-> RS232 chips i can connect but that is gonna be a lot of components for little bang. Seems this might be common enough problem that people have created a dedicated chip for it.<br> <br> cheers<br> Anders<br> </div> <br> -------------------------------------------------------------------------<br> This SF.net email is sponsored by DB2 Express<br> Download DB2 Express C - the FREE version of DB2 express and take<br> control of your XML. No limits. Just data. Click to get it now. <br> <a onclick="return top.js.OpenExtLink(window,event,this)" href="http://sourceforge.net/powerbar/db2/" target="_blank">http://sourceforge.net/powerbar/db2/</a><br> _______________________________________________<br> gumstix-users mailing list <br> <a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:gum...@li...">gum...@li...</a><br> <a onclick="return top.js.OpenExtLink(window,event,this)" href="https://lists.sourceforge.net/lists/listinfo/gumstix-users" target="_blank">https://lists.sourceforge.net/lists/listinfo/gumstix-users</a><br> <br> </blockquote> </div> <br> <pre wrap=""> <hr size="4" width="90%"> ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. <a class="moz-txt-link-freetext" href="http://sourceforge.net/powerbar/db2/">http://sourceforge.net/powerbar/db2/</a></pre> <pre wrap=""> <hr size="4" width="90%"> _______________________________________________ gumstix-users mailing list <a class="moz-txt-link-abbreviated" href="mailto:gum...@li...">gum...@li...</a> <a class="moz-txt-link-freetext" href="https://lists.sourceforge.net/lists/listinfo/gumstix-users">https://lists.sourceforge.net/lists/listinfo/gumstix-users</a> </pre> </blockquote> </body> </html> |
From: Marc N. <gee...@gm...> - 2007-05-28 22:31:07
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On 5/28/07, Dave Hylands <dhy...@gm...> wrote: > > HI Anders, > > > Can you recommend any voltage level converters? > > It depends on what you're trying to do. Anders, I use the Sparkfun boards. Either a cheap kit: http://www.sparkfun.com/commerce/product_info.php?products_id=133 Or pre-made board: http://www.sparkfun.com/commerce/product_info.php?products_id=449 Given that's my second plug for Sparkfun today, I to have to insist I'm just a happy customer! :D -marc |
From: Neil J. <nja...@gm...> - 2007-05-29 00:24:05
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Yep, Sparkfun has some great stuff.. Practically every sensor connected to my Gumstix came from them (accelerometers, gyros, altitude, compass, temp/humidity, GPS, ultrasonic range finders, CCD camera, etc..) On 5/28/07, Marc Nicholas <gee...@gm...> wrote: > > > > On 5/28/07, Dave Hylands <dhy...@gm...> wrote: > > > > HI Anders, > > > > > Can you recommend any voltage level converters? > > > > It depends on what you're trying to do. > > > Anders, > > I use the Sparkfun boards. Either a cheap kit: > > http://www.sparkfun.com/commerce/product_info.php?products_id=133 > > Or pre-made board: > > http://www.sparkfun.com/commerce/product_info.php?products_id=449 > > Given that's my second plug for Sparkfun today, I to have to insist I'm > just a happy customer! :D > > -marc > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > |