Guru
Joined: 08/02/2015
Location: New ZealandPosts: 1255
| Posted: 10:39pm 11 Aug 2021 |
Have made some changes in the design, decided to use both digital (74HC251D) and analog multiplexers (CD74HC4051) to connect the cpu to various zone sensors and alarm outputs.
Semi static relay and Led outputs are connected via High power serial shift registers, type NPIC6C596A-Q100.
Schematic below:
I will also use some of design ideas in the Pico H-Bridge driver module, then get on and do both PCB's; I do like the PI Pico, its an interesting cpu to play with, I just hope they bring out a revision to fix the broken interrupts and threading.
Mike