View Full Version : Is it OK to leave the reset line floating?

05-23-2010, 09:16 AM
My bicycle navigation project will use a GPS, compass module, accelerometer, and hopefully data logging via uSD card. All of the stuff basically works on my demo board (but not all at once since it won't all fit). It will be battery powered, of course. I am finally at the stage where I am learning Eagle and beginning to draw the schematic. I will not have enough room or battery power to have an on-board USB to serial, so I will use an external Prop Plug. I know the DTR needs to pulse the reset line, and is pulled down via an open collector. Since during operation my reset line will not be attached to the Prop Plug, is it OK to leave it float? Do I need to protect it from stray noise in some manner?

Thanks for any ideas.


05-23-2010, 09:19 AM
There's an internal pullup resistor so yes it is okay.


05-23-2010, 09:30 AM
Cool, thanks Kye.

Phil Pilgrim (PhiPi)
05-23-2010, 09:32 AM
The internal pullup is active only if BOEn is pulled low.