Quoting from a manufacture email;
Regarding the display:
We have two types of OLED displays, graphic and character.
Character displays are going to be much easier to just pick up and start talking to. They do not actually process ASCII text directly but depending on the level of abstraction you are willing to provide to the students (in a library for example), you could present it as though it does "speak" ASCII.
Graphics display are a whole different thing. Because graphic displays (generally) have no concept of a "font" they are incapable of naturally displaying text but again, depending on the layer of abstraction you provide, you can present as easy an interface (API) as you'd like.
Graphic displays are, for example, capable of displaying a bitmap if the bitmap is already in the exact format the display is expecting. OR you could provide a library that can translate ANY bitmap into the format the display wants so the students don't have to think about it.
A little bit off the mark as far as OLEDs, if you look at our line of intelligent displays, https://www.crystalfontz.com/product/cfa634tmiku as an example, they do "speak" ASCII. They are a little bit pricier but that's because the work (API) I described above, is being handled by the on-board microcontroller.
I hope this helps you get some ideas of what would be most useful. Please let me know if we can explain anything further or if you'd like more specific information on a/some particular display(s).
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