Hi all, I am aware this may be a newbie question but my google fu did not help at all.

I have a ti89 and a ti nspire (the first model). I used the ti 89 with ti basic long ago but I remember I wrote programs directly on the calculator.

Now I would like to develop my programs on a computer and when they are stable upload them on the calculator.

How do I do that?
Ideally I would use something like notepad++, then convert the plain text file in the format for TI basic and use it on the calculator. But I did not find any way to do this.

For the ti nspire, after figuring out how to upgrade to the last OS (there is a troubleshooting article that clarifies this), I was able to upload lua files using the luna 0.3 converter.

The problem in that I don't find how can I make programs that are not in lua (lua is very fast but oriented to graphics, so not really usable for math results).

On the web I read the "ti basic developer page" that suggests "graph link" or "ti connect" to work with the ti 89, but those programs seems not to work with windows 10 and cannot be used with the ti nspire.

So how do I program on the computer to then upload the program on the calculator?
Because programming directly on the calculator may be possible, but for very short programs.

Thanks for the help.

Graph link should be included in the USB to mini USB cable that came with the calculator(s). A version of TI-Connect should be available for your N-spire (I don't know if 89's are supported).
Try this link:
https://education.ti.com/en/products/computer-software/ti-nspire-computer-link

Edit:
With TI-Connect CE, which is what I use, there is a program editor, so I assume the linking software for the N-spire also contains one.

Thanks for the quick answer.

In the meanwhile I found this https://www.cemetech.net/sc/ for the ti 89 (although online, I'm not always online, but maybe there is a version for computer somewhere).

The ti nspire computer link does not have a way to edit programs. I do not have the original usb cable (you know, ebay), but graph link can be downloaded from the ti site so I may try some more to find out a way.

The main problem seems how to create ti nspire programs, it seems that with the ti nspire I should need the nspire student software.

edit: other possible lead https://tiplanet.org/forum/viewtopic.php?f=15&t=10498

Well, there is SourceCoder like you found, as well as TokenIDE (though I'm not sure if it exports for the ti89)

https://www.cemetech.net/programs/index.php?mode=file&id=515

Thanks. It seems that the nspire allows ti-basic programs only through the nspire student software.

Otherwise I have lua + variable export: https://inspired-lua.org/index.php/2011/08/save-a-high-score-without-cheating-possibility/ but it is very clumsy nevertheless if I do not have a complete program but I use programming for exploration and then manual checks.

If one has a "final" program then lua + luna 0.3 should be fine.