New Update for MacSim

26 August 2015

I am pleased to announce a new update to MacSim. It's been a long time coming and it nearly didn't happen, so I thought I'd explain what went wrong.

While working on the previous version of MacSim I thought I’d take some time out to implement one of the peripherals - a timer - to see how it went and if I could integrate it into MacSim without too many changes. Things went pretty well for a while, but at some point before I’d got more than a few of the different timer modes ‘working’ it all started going south. Every time I modified one part of the timer in order to get it to work, other parts would start behaving incorrectly.

I spent nearly 3 weeks running test programs on my simulator and comparing the results with AVR Studio. The results would often be identical for a while but then would begin to differ slightly, so I’d make a small change to the timer code to fix it but that would then cause other problems. At some point I more or less gave up, thinking that a microcontroller simulator without any peripherals wouldn't be that useful and I didn’t feel like spending ages futzing about trying to make it work. So the project languished until…

A few months ago while updating some projects that use a common framework I have been working on, I took another look at MacSim to see if it was worth updating to use the new framework. I’d really enjoyed working on it at the time ( apart from the last couple of weeks ) and it seemed a bit of a shame just to let it die. I was actually pretty close to getting the core working really well when I’d abandoned it and it would surely be moderately useful even without any peripherals. A few weeks work would get it up to date and hopefully I could then gradually add a few improvements that I had planned all along.

I even started thinking that I’d probably been a bit too hard with the timer testing. I had written some rather pathological code - changing timer modes just as the timer hit top or bottom and things like that, so maybe if I stuck to more realistic testing things work work out better!

So that is basically it. The simulator has been extensively updated and is working well and I am looking forward to implementing some improvements. There may be some incorrect instructions, so if you see any please let me know as they shouldn't be too hard to fix.

Website Refresh

25 August 2015

After quite a few years, it's time for a refresh. The new website is a lot simpler and cleaner and should load much faster.