Switch On Switch Off and Sleep and Wake Up

Power Switch

It's been a while, since I switched on blog.  We make  SCADA technology which has to be there when the chips are down - powered down that is.  Something as simple as a Power Switch can create a whole design controversy.  This blog post is a discussion of how simple something like a Power Switch can get.

Front and centre on the SCD5200 CPU is a big red power switch. It has two states, On and Off.  What I like about this is that is means what it says.  When you switch it on.  Power is applied to the brain of the CPU and it's bus connectors and off you go things start up and operate.  Switch it off, and the power is disconnected again and everything goes dead. Or does it ?..