Re: gEDA-user: ne555 timer

[Werner Hoch <werner.ho@xxxxxx>]

Hi Marc,

just take a look at the block diagramm of the circuit
http://www.fairchildsemi.com/ds/NE/NE555.pdf

On Thursday 19 January 2006 22:02, Marc wrote:
> ne555 timer
>
> 1 gnd            = pwr
> 2 trigger      =
> 3 output       = out
> 4 reset         =
> 5 control v   =
> 6 threshold =
> 7 discharge =
> 8 vcc            = pwr

Trigger is a high impedanz OPV input --> input
Threshold too --> input
Discharge has a transistor with open collector --> open collector
Reset is a transistor basis --> I'd suggest input or passiv here
Control voltage has a 2/3 voltage divider --> passiv

> what should the following pintypes be set to pls
> and what if a pin is unused on a chip what do you set it as

If  a pin is not connected use passiv. This is in my opinion the savest 
option as a DRC should not complain about it if you connect it for 
example to a different signal for cooling, mounting, ... reasons.

regards
Werner