need some help with multiplexer

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi.
i am trying to setup a alarm system using reed switchs (8) and a multiplexer 74LS151 i need some help with the coding to read the output from the 74LS151, i can control the selection of the port on the IC but need to read the output and match with the control selection.
i am a newbie at this would be grateful for some guidance i have a drawing of me setup but am not sure how show it on the forum.

thanks
chilliman :frowning:

2

Thanks for the info i will read and do some testing and see how i go .

chilliman

3

The strobe can be tied to ground, so it will be three lines vs. three lines MUX/PISO.

For an LS chip all inputs should be HIGH by default, as an internal 30k or so goes to Vcc.

As a simple extension the 24-pins '150 will multiplex 16 lines...