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A project log for nWatch

Selfmade watch that helps You learn STM32 programming.

Peter WasilewskiPeter Wasilewski 10/11/2015 at 19:100 Comments

I'm sorry for not writing for that long, but I have a lot of stuff going on right now. Doesn't mean I find no time for the watch, though. During this time I made some changes in the software part of the project. I decided to use Stemwin for certing graphics such as icons, menus, lists, buttons. It's really flexible so it fits my expectations. What's more important it handles the alpha channel, reading from the display, so I don't have to worry about wiping out the screen after I display something. On the pictures below You can see my test apps made with Stemwin.

Another feature of this lib is that it's able to decode jpeg, png anf gif images. However displaying these images may be quite slow if You don't find a way to display them using DMA transfer not pixel-by-pixel. I'm sure it's possible, but the decode process of jpeg file took to long for my video purposes. That's why I decided to give libjpeg another try. I succeded this time. It turned out that this lib allocates big memory blocks on the stack. The sollution was to increase the stack. Now when It's fully functional I have about 20 FPS. I think it can be higher if I spend some time on it.

Here's a video of a video ;)


I decided to use FreeRTOS in my project. I think it's another step forward. I know it's not going to be easy to develop a fully functional device with FreeRTOS for a newbie like me. Till now I managed to run FreeRTOS with 2 tasks, one main, and one for the graphics refresh ( background).

I'll try to write more often, but I cant promise that. Hmm that's all for this log, I guess. See You !

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