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Topic: why are A0 & A1 always high even when i have nothing connected? (Read 738 times) previous topic - next topic

TECH GEEK

Mar 18, 2011, 02:18 pm Last Edit: Mar 18, 2011, 02:23 pm by TECH GEEK Reason: 1
i'm useing an ethernet shield SD on a arduino mega 1280... however whenever i have it connected A0 & A1 read high, why is this?
also what is the maximum size the micro SD card can be and still function with the shield?
As always... Thanks for posting!!!

pluggy

Do  a little research on floating pins, its perfectly normal on very high impedance inputs as used on the Arduino. If you want it to read low, you could connect a 10 k resistor between Gnd and the pin you want to read low (whats known as a pull-down resistor).
http://pluggy.is-a-geek.com/index.html

TECH GEEK

i connected  an led from each pin (seperatly) then to ground. the led lit up as if the pins were shorted... are they?
As always... Thanks for posting!!!

TECH GEEK

As always... Thanks for posting!!!

TECH GEEK

i guess that makes sense... what about the max size of the sd card?
As always... Thanks for posting!!!

TECH GEEK

As always... Thanks for posting!!!

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