How do you keep time in ti83p family ASM programs - Cemetech | Forum

rondn · 18 Dec 2020 12:08:26 am

I've been working on my first game for my ti-84 plus. I've been doing everything from scratch, and was just working on the basic tile routines. But I just realized, I have no idea how to keep track of time so that I know what frame of my animation is supposed to be drawn. I've been looking around various tutorials and wikiTI, and I can't seem to find any information on how this is done on the ti-83 plus.

It seems like it could be done with the timers that the TI-83 Plus SE and better have at ports $30-$38, but considering that the vast majority of games are also compatible with the original 83-plus, it seems like there must be another more popular approach. It seems like there must be documentation on this somewhere, but I think I just need someone to push me in the right direction. Can someone give me a hand here?
Thanks,
Ron

tr1p1ea · 18 Dec 2020 06:29:41 am

It is an interesting question because a few years ago the use of crystal timers would have split the userbase ... however I'm not sure how many potential users there are out there that still use the og 83+?

The 83+ timers are likely influenced by outside factors such as cpu speed and battery life, so there are potentially some real accuracy challenges. (https://wikiti.brandonw.net/index.php?title=83Plus:Ports:04)

I think it would be safe to use crystal timers as I would assume most are using > 83+SE which was released almost 20 years ago?

rondn · 18 Dec 2020 11:34:42 am

Thanks. So looking at the article you linked me, you're saying that what you can do is set the frequency of that timer through port 04 and then when it hits zero it calls an interrupt, right? I'm thinking I'll do like you suggested and use the port $30 timers instead. Interrupts are one thing that I have not learned how to use yet, so I like how those timers just let you read the current value directly.

I think you have a good point about the my potential 83+ userbase being pretty small. I mean even if I do finish my game probably no one will want to play it. Although in general it seems like a lot of people still have that model. I mean they still sell them here in Canada and it's the cheapest model.

Anyway, that's enough rambling. Thanks for your help.