From: Torchris <chr...@ro...> - 2008-09-11 15:21:39
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Just a final update/problem. When I try to use ttyS1 (the port closest to the power connector on the consoleLCD) with the SerialLCD it doesn't work and it seems to hang up the Gumstix. Interestingly, ttyS1 works fine when connected to a terminal program, so it works, but there must be something odd with the connection to the SerialLCD unit. Thanks all! - Chris Torchris wrote: > > Hi Dave, > > Many thanks! > > Works like a charm!! I just had to jumper from the shell of the power > connector on the Gumstix to the GND wire on the SerialLCD. > > Of course, I should have remembered all this "reference ground" stuff from > when I got the SerialLCD to begin with since it took me quite a while to > figure it all out. > > Anyway, this gives me another tool to troubleshoot serial on the Gumstix. > > regards, > > Chris > > > Dave Hylands wrote: >> >> Hi Torchris, >> >>> Actually, the Sparkfun only has a connector for Rx, GND & -5 VDC. It >>> uses TTL >>> level and then I run it through a TTL-RS232 converter. >>> >>> I believe I have figured out the problem, but I'm not sure what the >>> answer >>> would be. I usually power the SerialLCD off of the USB from my PC which >>> provides a correct reference ground which is why it works fine with my >>> PC - >>> however, it won't work off of the Gumstix when powered by my PC's USB. >> >> It's important that the grounds be shared between your gumstix and the >> SerLCD. Since all of the voltages are relative to ground, if the >> ground on your SerLCD isn't connected to the ground on your gumstix, >> then they can be several volts apart. What normally happens is that >> the ground floats with an AC reference (coming from the wallwart). >> >>> I just tried to power the SerialLCD off of my GumStix ConsoleLCD USB >>> port >>> and it seems like it doesn't generate enough power to run the SerialLCD. >> >> The SerLCD only needs 60 mA, so I don't think that's the problem. Did >> you check to see if the USB connector actually has 5v on it? >> >>> Any thoughts on getting that reference ground off of the Gumstix? Here >>> is >>> the datasheet on the SerialLCD: >> >> Just connect the ground from the USB connector, or from any of the >> other connectors to the ground on the serialLCD. If you're going to >> power the serialLCD from the PC, then you need to connect the PC >> ground to the serialLCD as well. >> >> -- >> Dave Hylands >> Vancouver, BC, Canada >> http://www.DaveHylands.com/ >> >> ------------------------------------------------------------------------- >> This SF.Net email is sponsored by the Moblin Your Move Developer's >> challenge >> Build the coolest Linux based applications with Moblin SDK & win great >> prizes >> Grand prize is a trip for two to an Open Source event anywhere in the >> world >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >> _______________________________________________ >> gumstix-users mailing list >> gum...@li... >> https://lists.sourceforge.net/lists/listinfo/gumstix-users >> >> > > -- View this message in context: http://www.nabble.com/Using-consoleLCD-serial-ports-tp19404381p19436700.html Sent from the Gumstix mailing list archive at Nabble.com. |