Commercial software projects
I started my working life as a software engineer working on major projects with million+ LOC. As my career has moved into test and leadership software development reduced considerably but never quite disappeared.
Motorola mobile radio software development
I maintained and enhanced firmware for 20+ variants of the CQM6000 product range. This included major features and bug fixes in MCS51 assembler
As described on the Storno site the CQM6000 was undoubtably the most versatile radio Storno produced.
MX3000 & GP300
I developed customer specific software for the MX3000 and GP300 radio models in 68HC11 assembler from requirements trhough to code and test. The MX3000 was particularly interesting to work on with a second processor managing the UI. The UI was implemented as interpreted virtual machine programmed with its own byte-codes or assembly language (an advanced approach in its day). Customer solutions often required coding for the 2 real processors, the VM and PC based service software.
I developed all firmware from reset vector upwards for an additional processor module that fitted into an extended version of the MX3000. This module contained mercury switches which triggered the radio to make an emergency call if there was no movement or the radio was tilted.
The Crypto Museum has a good description of the module and further photos.