Hey, I am new to the forums, but I was wondering if it is possible to basically convert my TI 84 Plus CE to a TI 84 Plus CSE. I don't think it is possible because of the different hardware, but are there possibly any ASM programmes that allow this? I'm mainly wondering because there isn't a Doors CS for TI 84 Plus CE yet, and the last thing I saw for it was from December 10th, 2015, and it was said to be released in the beginning of 2016, but it hasn't been released.

No, and there's not much of a reason to other than said APIs. The eZ80 has a Z80 compatibility mode but you'd essentially have to change out the whole operating system to use it. Simple ASM programs should be easily portable from Z80 to eZ80 with little or no effort required.

Additionally, the TI-84 Plus CE uses memory-mapped I/O, whereas the CSE uses port-mapped I/O. The I/O mapping is one of the least of your concerns, due to the significantly different hardware between the two models.

Is the reason you want to convert your CE to a CSE because you want to use certain programs that requires DoorsCSE?

KermM is working on finishing DoorsCE, so in a few months (hopefully less) you will be able to use those programs. If you want to check out the development thread, it's here.

In the meantime, maybe you could convince someone to port one of those programs....