However, the TI cartridges could also contain a different type of ROM called "GROM". Which I believe was "Graphics ROM".
Jup, although, it wasn't really related to graphics at all. More due the fact, that its primary usage within the TI99/4 was to hold GPL code - which itself stands for Graphic Programming Language.
There was also GRAM, if memory serves, ...
But for some reason, you could only work with 28 sprites instead of the maximum of 32. So, what was the reason behind this?
One reason may have been space.
Of the 16 KiB RAM, build-in TI-BASIC uses 2 KiB for screen handling (including 80 bytes line buffer) (*1), leaving a bit less than 12 KiB for programm and data.
For Extended BASIC it is essential to be ...