From: Arnar B. <ar...@gm...> - 2007-02-03 23:02:18
|
Hi folks, The wiki points to this page: http://www.botkin.org/dale/rs232_interface.htm which contains a schematic for an extremely simple RS232 to TTL levels serial adapter. Has anyone tried this? I know I can buy a ready-made converter, but it sounds like a neat idea. I'm still waiting for my gumstix to arrive, so in the meantime I set the converter up in a circuit simulator. Things seem to work, except that a mark sent from the ttl side comes out as 0V on the rs232 side. The spec says a mark is anything -3 to -15V, but the gumstix wiki states that "most" computers extends that to 0 to -15 V. Is this likely to be a problem? thanks, Arnar |
From: Dave H. <dhy...@gm...> - 2007-02-04 00:09:22
|
Hi Arnar, > I'm still waiting for my gumstix to arrive, so in the meantime I set > the converter up in a circuit simulator. Things seem to work, except > that a mark sent from the ttl side comes out as 0V on the rs232 side. > The spec says a mark is anything -3 to -15V, but the gumstix wiki > states that "most" computers extends that to 0 to -15 V. Is this > likely to be a problem? With most modern computers it should work fine. The only way to know for sure is to try it with your computer. -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |
From: Arnar B. <ar...@gm...> - 2007-02-04 02:02:49
|
Hi Dave, On 2/4/07, Dave Hylands <dhy...@gm...> wrote: > Hi Arnar, > > > I'm still waiting for my gumstix to arrive, so in the meantime I set > > the converter up in a circuit simulator. Things seem to work, except > > that a mark sent from the ttl side comes out as 0V on the rs232 side. > > The spec says a mark is anything -3 to -15V, but the gumstix wiki > > states that "most" computers extends that to 0 to -15 V. Is this > > likely to be a problem? > > With most modern computers it should work fine. The only way to know > for sure is to try it with your computer. Ok great, I'll give it a try. Thanks. Arnar |