PDA

View Full Version : Pull down network... Why doesn't it make sense...



Kaos Kidd
08-15-2006, 11:43 PM
I'm trying my hardest to see how this works... and for some reason, I just cant see it.
What I need is either a logic HI or LOW (IE Not floating) on the inputs to the PCF8574.
So, all the resistors have one end tied to ground...
The other end goes through the DIP switch... which goes into the inputs of the PCS8574.
Ok, no problem here.· Now, if I tie all the inputs to the PCF8574 to HI, will they all appear as HI no matter what the position the DIP is in?
Tieing the inputs to GND doesn't seem to work either, so I've either missed the boat completly... or...
Well, I won't consider the or here... please point out my wiring error...



http://forums.parallax.com/attachment.php?attachmentid=42893

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
-------------------------------------------------------------------------

Propeller + Hardware - extra bits for the bit bucket =· 1 Coffeeless KaosKidd
-------------------------------------------------------------------------

Paul Baker
08-16-2006, 12:23 AM
You have the resistors on the wrong side of the switch, they must be on the output side of the switch:



^ Vdd
|
+-- S -+-- Out
|
R
|
V Gnd



▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
...

Kaos Kidd
08-16-2006, 12:26 AM
Thanks Paul...
(This thread should be moved shortly... it's off topic... I wasnt paying attention when posting... sorry guys...)

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
-------------------------------------------------------------------------

Propeller + Hardware - extra bits for the bit bucket =· 1 Coffeeless KaosKidd
-------------------------------------------------------------------------

·

Chris Savage
08-16-2006, 12:43 AM
This thread is being moved from the·Propeller Chip·Forum to the·Sandbox Forum.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)