From: Dave H. <dhy...@gm...> - 2006-11-08 18:49:15
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Hi Chris, > I thought you only needed to add the resistor if you had a pre J-fab > robostix? I received mine about a month ago, so I assumed it was J-fab. I am > looking at this page: > http://docswiki.gumstix.org/Robostix_Mods#Pullup_Resistor Hmmm. I think that I'll have to revise that. With the robostix, the RxD on the gumstix conector is a 5v logic level line. It goes through a voltage converter to become 3.3v. The pullup on the post-J fab gumstix (note that the fab level is referring to the gumstix board and not the robostix board) is on this 3.3v RxD line. Since the voltage translator on the robostix will always be driving this, that particular resistor becomes irrelevant. What's important is that there be a resistor on the 5v RxD line, so that when no serial adapter is plugged in, it sits in the idle state. -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |