With caching:
size 16 - tested up to 216 characters without issue
size 32 - tested up to 108 characters without issue
size 64 - 37 character limit before corruption
Unfortunately the cache is not smart enough to allow even a single char extra.
This is why I did not only setup the font-cache but I also showed how to keep track of it.
So the limit is the size of the cache and of course you get less entries with bigger glyphs.
Outside the display-list itself there is this:
EVE_cmd_fontcachequery(&fonttotal, &fontused);
And then there is this:
EVE_cmd_text_var_burst(180, 530, FONT_NOTO040, EVE_OPT_FORMAT, "Fontcache total: %d used: %d", 2, fonttotal, fontused);
And the result with my Notosans 40 is: "Fontcache total: 115 used: 17"
When you count, this line has 17 different characters.
The size of the font-cache in my example is 67648 bytes since it is defined to start at 0x00ee000 and the size is defined as 0x00fe840 - 0x00ee000.
#define MEM_FONTCACHE 0x000ee000
#define MEM_FONT_INCON24 0x000fe840
#define SIZE_FONTCACHE (MEM_FONT_INCON24 - MEM_FONTCACHE)
Change the first define to a lower address and you have a bigger font-cache.
I just changed it to 0x000e0000 and now the "total" is 213.
Unfortunately this is all trial and error since the font size is rather meaningless in terms of absolute numbers.
Even more so since the ASTC format seems to require full bytes and so different font sizes end up
with the same sizes for the .glyph files.
The file NotoSans-Regular_40_ASTC.glyph is 143KB and has 187 glyphs.
To make the font-cache 187 glyphs larged I needed to set the lower address to 0x000e3b00.
This makes a size of 107KB to cache every glyph which is still a win compared to copying the complete .glyph to RAM_G.
So any realistic size to set the cache at is less than size of the .glyph file.
Annother thing to keep in mind, the font-cache has to be big enough to store every unique glyph to be used
in two consecutive frames.
So it needs to be big enough to account for extra chars if you swap pages.
I just added an additional line:
EVE_cmd_text_burst(180, 560, FONT_NOTO040, 0, "The quick brown fox jumps over the lazy dog! 1234567890");
And the "used" jumped to 41.
So it is rather unlikely that there is an issue with room for 115 glyphs.
A good rule of thumb might be to set the size of the cache to half of the .glyph for a first try, maybe 2/3.