The Perils of NMI - NMI is a critical resource, yet all too often it's misused. Using the Z180 MMU - Extend your Z80 address spaces to 1 Mb with the Z180. Here's how they work. Here's some algorithms to make it easier to compute complex trig functions. VCO Based Sensors - VCOs can form a clever way to digitize analog data.
Software alone suffices.
Here's the code. Smoothing Digital Inputs - There's a lot of way ways to debounce digital inputs. A few are listed in this article. Speed Kills - Data comm over cheap serial links might be more cost effective than other, faster, options. As a designer, you can make decisions that greatly impact the environment.