Short update on the software

A project log for SDA - The best new PDA

Do you miss those old small devices in your palm? Don't be sad, you can always build your own!

brtnstbrtnst 09/09/2018 at 22:200 Comments

For the past half a year I was mostly working on the software. There are few new software features and the simplest way to show them was to make an update video.

Task switching

The largest new feature is task switching. It is only task switching and not multitasking, only one application is running at any given time. I made some modifications to the graphics library and the application runtime so the full state of a running application can be stored on the SD card. When tasks are switched, the currently running task is stored and the new task is launched or restored.

New applications

There are few new apps, most of them were described in previous logs (MP3 Player, GPS, snake), but there are also few new ones. SDA Commander is a simple file manager, it can browse folders, edit text files, show pictures and run executables (SVS scripts). I also met one of the design milestones and that is self-programmability of the PDA. It is not very usefull for now (it is limited to about 1kb of code), but as a proof-of concept it works. I had some problems typing in the video and that is mostly because I was looking on the PDA through the camera viewfinder.

Also the overall system stability was improved, in the first video I had to reset the device at the start of each take to get consistent results. Here I just picked up the PDA, did the demo and everything worked without a glitch while the system was running for about fourteen days with four hours of screen on time.

Since I am waiting for the PCBs to continue with the next design iteration of the hardware I am refactoring the code and writing some basic documentation for the SDA_OS github repo that will be up in a few weeks.